Rationale: Hereditary hemochromatosis (HH) is a hereditary disorder of iron metabolism. It is classified into 4 main types depending on the underlying genetic mutation: human hemochromatosis protein (HFE) (type 1), hemojuvelin (HJV) (type 2A), HAMP (type 2B), transferrin receptor-2 (TFER2) (type 3), and ferroportin (type 4). Type 4 HH is divided into 2 subtypes according to different mutations: type 4A (classical ferroportin disease) and type 4B (non-classical ferroportin disease). Type 4B HH is a rare autosomal dominant disease that results from mutations in the Solute Carrier Family 40 member 1 (SLC40A1) gene, which encodes the iron transport protein ferroportin.

Patient concerns: Here we report 2 elderly Chinese Han men, who were brothers, presented with liver cirrhosis, diabetes mellitus, skin hyperpigmentation, hyperferritinaemia as well as high transferrin saturation.

Diagnosis: Subsequent genetic analyses identified a heterozygous mutation (p. Cys326Tyr) in the SLC40A1 gene in both patients.

Interventions: We treated the patient with iron chelator and followed up for 3 years.

Outcomes: Iron chelator helped to reduce the serum ferritin and improve the condition of target organs, including skin, pancreas, liver as well as pituitary.

Lessons: Type 4B HH is rare but usually tends to cause multiple organ dysfunction and even death. For those patients who have difficulty tolerating phlebotomy, iron chelator might be a good alternative.

Hepcidin (HAMP) is synthesized in the liver. It is a key ironregulatory hormone that controls systemic iron homeostasis. Cereblon (CRBN) and Kruppel-like factor 15 (KLF15) are known to regulate diverse physiological functions. In this study, we investigated the role of CRBN on hepatic hepcidin gene expression and production under gluconeogenic stimuli. Fasted mice as well as forskolin (FSK)- and glucagon (GLU)-treated mice had reduced serum iron levels but increased expression levels of hepatic Crbn and Klf15 and hepcidin secretion. MicroRNA (miRNA) expression analysis of fasted and Ad-Crbninfected mice revealed significant reduction of microRNA-639 (miR-639). Hepatic overexpression of Crbn elevated hepcidin expression and production along with Klf15 gene expression, whereas knockdown of Crbn and Klf15 markedly decreased FSK- and fasting-mediated induction of hepcidin gene expression and its biosynthesis in mouse livers and primary hepatocytes. Moreover, expression of KLF15 significantly increased the activity of hepcidin reporter gene. It was exclusively dependent on the KLF15-binding site identified within the hepcidin gene promoter. Overall, this study demonstrates that CRBN and KLF15 are novel mediators of gluconeogenic signal-induced hepcidin gene expression and production. Thus, CRBN and KLF15 might be novel potential therapeutic targets to intervene metabolic dysfunction.

Background: Hepcidin is a polypeptide hormone mainly produced by hepatocytes to modulate systemic iron balance. A drastic downregulation of the hepcidin gene was found in liver cancers. However, there is a paucity of information about the clinical significance of hepcidin gene downregulation in liver cancers.

Methods: Hepcidin expression profiles were assessed using multiple public datasets via several bioinformatics platforms. Clinical and pathological information was utilized to stratify patients for comparison. Patient survival outcomes were evaluated using the Kaplan-Meier plotter, a meta-analysis tool. Tumor immune infiltration was analyzed using the single sample gene set enrichment analysis (ssGSEA) approach on the Cancer Genome Atlas (TCGA) dataset. Hepcidin antagonist Fursultiamine was used to treat liver cancer HepG2 and Huh7 cells together with Sorafenib.

Results: Hepcidin gene was predominantly expressed in benign liver tissues but drastically decreased in liver cancer tissues. Hepcidin reduction in liver cancers correlated with risk factors like non-alcoholic fatty liver disease (NAFLD) and liver fibrosis, as well as cancer grade and tumor stage. Hepcidin downregulation was associated with a rapid cancer progression and worse disease-specific survival, especially in patients of the White race without alcohol consumption history. Hepcidin expression in liver cancer tissues positively correlated with the bone morphogenetic protein-6 (BPM6)/interleukin-6 (IL6) cytokines and cytotoxic immune infiltration. Blocking hepcidin action with its antagonist Fursultiamine moderately reduced Sorafenib-induced apoptotic cell death in HepG2 and Huh7 cells.

Conclusion: Hepcidin downregulation in liver cancers correlated with liver cancer risk factors, cancer aggressiveness, cytotoxic immune cell infiltration, and patient survival outcomes. BMP6/IL6 pathway insufficiency is a potential cause of hepcidin downregulation in liver cancers.

Keywords: HAMP; cancer survival; disease progression; liver cancer; tumor immune infiltration.

The large yellow croaker (Larimichthys crocea) aquaculture industry is suffering substantial financial losses caused by visceral white nodules disease resulting from Pseudomonas plecoglossicida infection. However, how L. crocea responds to P. plecoglossicida infection remains largely unknown. Here, we characterized the changes in the mRNA profile in the spleen of L. crocea upon P. plecoglossicida infection and explored the related defensive strategies. Sample clustering analysis and qRT-PCR indicated that P. plecoglossicida induced profound and reproducible transcriptome remodeling in the L. crocea spleen. Many innate immune-related genes, such as IL-17 signaling molecules, chemokines and chemokine receptors, complement components, TLR5 signaling molecules, and antimicrobial peptide hepcidins (Hamps), were upregulated by P. plecoglossicida and may play important roles in the L. crocea defense against P. plecoglossicida. The antibacterial activity of Hamp2-5 against P. plecoglossicida was further confirmed by using synthetic mature peptide of Hamp2-5. Additionally, significant enrichment of "Glycolysis/Gluconeogenesis", "Citrate cycle" and "Oxidative phosphorylation" pathways and a significant upregulation of all 6 rate-limiting enzyme genes (HK1, PFK, PKM, CS, IDH2, DLST) in the Glycolysis and Citrate cycle pathways in P. plecoglossicida-infected fish suggested that ATP synthesis may be accelerated to ensure energy supply in response to pathogenic infection. Altogether, our results not only identified the key immune-related genes and immune pathways that participated in the defense response of L. crocea against P. plecoglossicida, but also revealed a novel defensive strategy involving ATP synthesis in this species.

Keywords: ATP synthesis; Immune-related genes; Larimichthys crocea; Pseudomonas plecoglossicida; Transcriptome.

In response to herbivore attack, plants release large amounts of volatiles that can serve as attractants for the natural enemies of the attacking herbivores. Such responses are typically triggered by damage- and insect-associated factors. Cotton plants are somewhat peculiar because they release specific blends of volatiles in two waves in response to caterpillar attack. They first emit constitutively stored volatile compounds, and after about 24 h a second wave that includes various de novo synthesized compounds. The relative importance of damage-associated and insect associated-factors in this induction of cotton volatile emissions is not yet fully clear. We evaluated how cotton plants respond to mechanical damage and to the application of the oral secretion from the generalist lepidopteran pest Spodoptera exigua, by measuring the local and systemic emissions of volatile compounds from their leaves. Our results confirm that cotton plants respond to damage-associated molecular patterns (DAMPs) as well as to herbivore-associated molecular patterns (HAMPs) present in the caterpillars' oral secretion. Interestingly, a stronger response was observed for cotton plants that were treated with oral secretion from cotton-fed caterpillars than those fed on maize. We tested the possibility that volicitin, a common fatty acid-derived elicitor in caterpillar regurgitant plays a role in this difference. Volicitin and volicitin-like compounds were detected in equal amounts in the oral secretion of S. exigua fed on either cotton or maize leaves. We conclude that other elicitors must be involved. The identification of these eliciting cues is expected to contribute to the development of novel strategies to enhance the resistance of cotton plants to insect pests.

Keywords: Spodoptera spp.; cotton; damage-associated molecular patterns; herbivore-associated molecular patterns; plant indirect defenses; volatile emissions.

Hereditary hemochromatosis (HH) is an inherited iron overload disorder due to a deficiency of hepcidin, or a failure of hepcidin to degrade ferroportin. The most common form of HH, Type 1 HH, is most commonly due to a homozygous C282Y mutation in HFE and is relatively well understood in significance and action; however, other rare forms of HH (Types 2-4) exist and are more difficult to identify and diagnose in clinical practice. In this review, we describe the clinical characteristics of HH Type 2-4 and the mutation patterns that have been described in these conditions. We also review the different methods for genetic testing available in clinical practice and a pragmatic approach to the patient with suspected non-HFE HH.

Keywords: HAMP; ferroportin disease; hemochromatosis; hepcidin; juvenile hemochromatosis; non-HFE; transferrin-receptor 2.

The Aer2 receptor from Pseudomonas aeruginosa has an O₂-binding PAS-heme domain that stabilizes O₂ via a Trp residue in the distal heme pocket. Trp rotates ∼90° to bond with the ligand and initiate signaling. Although the isolated PAS domain is monomeric, both in solution and in a cyanide-bound crystal structure, an unliganded structure forms a dimer. An overlay of the two structures suggests possible signaling motions but also predicts implausible clashes at the dimer interface when the ligand is bound. Moreover, in a full-length Aer2 dimer, PAS is sandwiched between multiple N- and C-terminal HAMP domains, which would feasibly restrict PAS motions. To explore the PAS dimer interface and signal-induced motions in full-length Aer2, we introduced Cys substitutions and used thiol-reactive probes to examine in vivo accessibility and residue proximities under both aerobic and anaerobic conditions. In vivo, PAS dimers were retained in full-length Aer2 in the presence and absence of O₂, and the dimer interface was consistent with the isolated PAS dimer structure. O₂-mediated changes were also consistent with structural predictions in which the PAS N-terminal caps move apart and the C-terminal DxT region moves closer together. The DxT motif links PAS to the C-terminal HAMP domains and was critical for PAS-HAMP signaling. Removing the N-terminal HAMP domains altered the distal PAS dimer interface and prevented signaling, even after signal-on lesions were introduced into PAS. The N-terminal HAMP domains thus facilitate the O₂-dependent shift of PAS to the signal-on conformation, clarifying their role upstream of the PAS-sensing domain.

Background: Renal cell carcinoma (RCC) contributed to 403,262 new cases worldwide in 2018, which constitutes 2.2% of global cancer, nevertheless, sunitinib, one of the major targeted therapeutic agent for RCC, often developed invalid due to resistance. Emerging evidences suggested sunitinib can impact tumor environment which has been proven to be a vital factor for tumor progression.

Methods: In the present study, we used ssGSEA to extract the immune infiltrating abundance of clear cell RCC (ccRCC) and normal control samples from GSE65615, TCGA, and GTEx; key immune cells were determined by Student's t-test and univariable Cox analysis. Co-expression network combined with differentially expressed analysis was then applied to derive key immune-related genes for ccRCC, followed by the identification of hub genes using differential expression analysis. Subsequently, explorations and validations of the biological function and the immune-related and sunitinib-related characteristics were conducted in KEGG, TISIDB, Oncomine, ICGC, and GEO databases.

Results: We refined immature dendritic cells and central memory CD4 T cells which showed associations with sunitinib and ccRCC. Following, five hub genes (CRYBB1, RIMBP3C, CEACAM4, HAMP, and LYL1) were identified for their strong relationships with sunitinib and immune infiltration in ccRCC. Further validations in external data refined CRYBB1, CEACAM4, and HAMP which play a vital role in sunitinib resistance, immune infiltrations in ccRCC, and the development and progression of ccRCC. In conclusion, our findings could shed light on the resistance of sunitinib in ccRCC and provide novel biomarkers or drug targets for ccRCC.

Keywords: CEACAM4; CRYBB1; HAMP; renal cell carcinoma; sunitinib.

Increasing evidence has shown that tumor microenvironments are an important feature in clear cell renal cell carcinoma (ccRCC) carcinogenesis and therapeutic efficacy. In this study, two subtypes of ccRCC, high- and low-immune groups, were identified based on the immune gene datasets, of which the differential immune genes were identified accordingly. Furthermore, we constructed a risk prognosis model using five immune genes, specifically, AQP9, KIAA1429, HAMP, CCL13, and CCL21. This model was highly predictive of ccRCC clinical characteristics and showed potential for use in immunotherapy. Furthermore, the five identified genes were highly correlated with the abundance of B cells, CD4 T cells, CD8 T cells, macrophages, neutrophils, and dendritic cells in the tumor microenvironments. Among them, AQP9, KIAA1429, and HAMP exhibited significant prognostic potential. These findings indicate that monitoring and operating tumor microenvironments are of great significance for ccRCC prognosis and precise immunotherapy.

Obstructive sleep apnea (OSA) patients exhibit different degrees of cognitive impairment, which is related to the activation of reactive oxygen species (ROS) production by chronic intermittent hypoxia (CIH) and the deposition of iron in the brain. As a central regulator of iron homeostasis, whether hepcidin is involved in OSA-induced cognitive impairment has not been clarified. In order to simulate OSA, we established the mouse model by reducing the percentage of inspired O₂ (FiO₂) from 21% to 5%, 20 times/h for 8 h/day. We found hepcidin was rising during CIH, along with increasing iron levels and neuron loss. Then, we constructed a mouse with astrocyte-specific knockdown hepcidin gene (shHamp). During CIH exposure, the shHamp mice showed a lower level of total iron and neuronal iron in the hippocampus, via stabilizing ferroportin 1 (FPN1) and decreasing L-ferritin (FTL) levels, when compared with wild-type (WT) mice. Furthermore, the shHamp mice showed a decrease of ROS by downregulating the elevated NADPH oxidase (NOX2) and 4-hydroxynonenal (4-HNE) levels mediated by CIH. In addition, the shHamp mice presented improved cognitive deficit by improving synaptic plasticity and BDNF expression in the hippocampus when subjected to CIH. Therefore, our data revealed that highly expressed hepcidin might promote the degradation of FPN1, resulting in neuronal iron deposition, oxidative stress damage, reduced synaptic plasticity, and impaired cognitive performance during CIH exposure.

Background: Colorectal cancer (CRC) is one of the most common malignant tumors in the world. Ferroptosis is a newly defined form of cell death, distinguished by different morphology, biochemistry, and genetics, and involved in CRC progression and treatment. This study aims to establish a predictive model to elucidate the relationship between ferroptosis and prognosis of CRC patients, to explore the potential value of ferroptosis in therapeutic options.

Methods: The ferroptosis-related genes were obtained from the GeneCards and FerrDb websites. The limma R package was used to screen the differential ferroptosis-related genes (DEGs) in CRC from The Cancer Genome Atlas (TCGA) dataset. The least absolute shrinkage and selection operator (LASSO) and multivariate Cox regressions were to establish the 10-gene prognostic signature. The survival and receiver operating characteristic (ROC) curves were illustrated to evaluate the predictive effect of the signature. Besides, independent prognostic factors, downstream functional enrichment, drug sensitivity, somatic mutation status, and immune feature were analyzed. Moreover, all these conclusions were verified by using multiple datasets in International Cancer Genome Consortium (ICGC) and Gene Expression Omnibus (GEO).

Results: Ten ferroptosis-related gene signature (TFAP2C, SLC39A8, NOS2, HAMP, GDF15, FDFT1, CDKN2A, ALOX12, AKR1C1, ATP6V1G2) was established to predict the prognosis of CRC patients by Lasso cox analysis, demonstrating a good performance on Receiver operating characteristic (ROC) and Kaplan-Meier (K-M) analyses. The CRC patients in the high- or low-risk group showed significantly different fractions of immune cells, such as macrophage cells and CD8+ T cells. Drug sensitivity and somatic mutation status like TP53 were also closely associated with the risk scores.

Conclusions: In this study, we identified a novel ferroptosis-related 10-gene signature, which could effectively predict the prognosis and survival time of CRC patients, and provide meaningful clinical implications for targeted therapy or immunotherapy. Targeting ferroptosis is a good therapeutic option for CRC patients. Further studies are needed to reveal the underlying mechanisms of ferroptosis in CRC.

Keywords: colorectal cancer; drug sensitivity; ferroptosis; gene signature; prognostic model.

Cholangiocarcinoma (CHOL), the second most common malignant liver tumor, is clinically heterogeneous. In this study, we used gene expression profiles of CHOL obtained from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) databases to identify novel mutation signatures in CHOL. Hepcidin antimicrobial peptide (HAMP) was identified as a novel diagnostic biomarker for CHOL using the intersection of mutation analysis and receiver operating characteristic (ROC) analysis. We then explored the expression signatures of HAMP in CHOL. HAMP-related differentially expressed genes (DEGs) were selected for the identification of hub genes related to HAMP and for prognostic prediction model analysis. Gene set enrichment analysis (GSEA) showed that the HAMP-related DEGs were mainly enriched for signaling pathways related to cholangiocarcinoma development. Through immunohistochemistry validation, clinical cohorts analysis, and TCGA analysis, we investigated the association between HAMP and clinical parameters and found that decreased HAMP expression was correlated with advanced pathological grade and poor prognosis. Besides, we estimated the immune infiltration level in CHOL and its relationship with HAMP expression. The proportion of tumor-infiltrating cells revealed that gamma delta T cells and monocytes were positively correlated with HAMP expression. Besides, HAMP was also correlated with chemokine, CCL16. This evidence suggested that HAMP might contribute to immune activation in the CHOL microenvironment. Therefore, HAMP may play a synergistic role with these immune cells and chemokines to inhibit CHOL development. HAMP serves as a valuable biomarker in CHOL and is closely correlated with its progression.

Keywords: CIBERSORT; Cholangiocarcinoma; GSEA; HAMP; Immune microenvironment; Multi-omics.

Background: Several inherited diseases cause hyperferritinemia with or without iron overload. Differential diagnosis is complex and requires an extensive work-up. Currently, a clinical-guided approach to genetic tests is performed based on gene-by-gene sequencing. Although reasonable, this approach is expensive and time-consuming and Next Generation Sequencing (NGS) technology may provide cheaper and quicker large-scale DNA sequencing.

Methods: We analysed 36 patients with non-HFE-related hyperferritinemia. Liver iron concentration was measured in 33 by magnetic resonance. A panel of 25 iron related genes was designed using SureDesign software. Custom libraries were generated and then sequenced using Ion Torrent PGM.

Results: We identified six novel mutations in SLC40A1, three novel and one known mutation in TFR2, one known mutation and a de-novo deletion in HJV, and a novel mutation in HAMP in ten patients. In silico analyses supported the pathogenic role of the mutations.

Conclusions: Our results support the use of an NGS-based panel in selected patients with hyperferritinemia in a tertiary center for iron metabolism disorders. However, 26 out of 36 patients did not show genetic variants that can individually explain hyperferritinemia and/or iron overload suggesting the existence of other genetic defects or gene-gene and gene-environment interactions needing further studies.

Keywords: ferritin; ferroportin; hemochromatosis; hemojuvelin; hepcidin; iron overload; next generation sequencing; transferrin receptor 2.

Objective: To investigate the mechanism of activation of the signal transducer and activator of transcription 3 (STAT3) signal pathway in the process of retinopathy of prematurity (ROP). Methods: Sixty newborn Sprague-Dawley (SD) rats were randomly separated into the hyperoxia and air control groups (n = 30/in each group). The serum hepcidin level on 21 d was measured using the enzyme-linked immunosorbent assay (ELISA). The expression of HAMP and STAT3 protein in the liver was determined using reverse transcription-polymerase chain reaction (RT-PCR) and western blotting. Retinal neovasculature was evaluated by hematoxylin and eosin (HE) stain and fluorescein lectin. The retinal endothelial cells were treated with 250 μmol/L cobalt chloride for 72 h and added S3I-201. The STAT3 level was determined by western blotting. Results: The expression of STAT3 protein increased significantly after hyperoxia stimulation. The expression of HAMP mRNA in the hyperoxia group was significantly higher than that of the control group. The proliferation of retinal cells was inhibited, and the expression of STAT3 was increased. No significant difference was noted in vascular endothelial growth factor (VEGF) mRNA. The expression of STAT3 and VEGF mRNA was significantly reduced. Conclusion: The activation of the STAT3 signal pathway increased hepcidin expression, contributing to the pathogenesis of ROP. S3I-201 inhibited the expression of STAT3 and VEGF mRNA levels. This information provides potential novel therapeutic approach to the prevention and treatment of ROP.

Keywords: HAMP; STAT3; STAT3 signal pathway; retinopathy of prematurity; vascular endothelial growth factor.

Numerous harmful microorganisms and insect pests have the ability to cause plant infections or damage, which is mostly controlled by toxic chemical agents. These chemical compounds and their derivatives exhibit hazardous effects on habitats and human life too. Hence, there's a need to develop novel, more effective and safe bio-control agents. A variety of microbes such as viruses, bacteria, and fungi possess a great potential to fight against phytopathogens and thus can be used as bio-control agents instead of harmful chemical compounds. These naturally occurring microorganisms are applied to the plants in order to control phytopathogens. Moreover, practicing them appropriately for agriculture management can be a way towards a sustainable approach. The MBCAs follow various modes of action and act as elicitors where they induce a signal to activate plant defense mechanisms against a variety of pathogens. MBCAs control phytopathogens and help in disease suppression through the production of enzymes, antimicrobial compounds, antagonist activity involving hyper-parasitism, induced resistance, competitive inhibition, etc. Efficient recognition of pathogens and prompt defensive response are key factors of induced resistance in plants. This resistance phenomenon is pertaining to a complex cascade that involves an increased amount of defensive proteins, salicylic acid (SA), or induction of signaling pathways dependent on plant hormones. Although, there's a dearth of information about the exact mechanism of plant-induced resistance, the studies conducted at the physiological, biochemical and genetic levels. These studies tried to explain a series of plant defensive responses triggered by bio-control agents that may enhance the defensive capacity of plants. Several natural and recombinant microorganisms are commercially available as bio-control agents that mainly include strains of Bacillus, Pseudomonads and Trichoderma. However, the complete understanding of microbial bio-control agents and their interactions at cellular and molecular levels will facilitate the screening of effective and eco-friendly bio-agents, thereby increasing the scope of MBCAs. This article is a comprehensive review that highlights the importance of microbial agents as elicitors in the activation and regulation of plant defense mechanisms in response to a variety of pathogens.

Keywords: ABA, Abscisic acid; BABA, β-Aminobutyric acid; BTH, Benzothiadiazole; CKRI, Cross kingdom RNA interference; DAMPs, Damage-associated molecular patterns; Defense mechanism; ET, Ethylene; ETI, Effector-triggered immunity; Elicitors; Fe, Iron; GSH, Glutathione; HAMP, Herbivore-associated molecular patterns; HG, Heptaglucan; HIR, Herbivore induced resistance; HRs, Hormonal receptors; ISR, Induced systemic resistance; ISS, Induced systemic susceptibility; Induced resistance; JA, Jasmonic acid; LAR, Local acquired resistance; LPS, Lipopolysaccharides; MAMPs, Microbe-associated molecular patterns; MBCAs, Microbial biological control agents; Microbiological bio-control agent; N, Nitrogen; NO, Nitric oxide; P, Phosphorous; PAMPs, Pathogen-associated molecular patterns; PGP, Plant growth promotion; PGPB, Plant growth promoting bacteria; PGPF, Plant growth promoting fungi; PGPR, Plant growth promoting rhizobacteria; PRPs, Pathogenesis-related proteins; PRRs, Pattern recognition receptors; PTI, Pattern triggered immunity; Plant defense; Plant disease; RLKs, Receptor-like-kinases; RLPs, Receptor-like-proteins; ROS, Reactive oxygen species; SA, Salicylic acid; SAR, Systemic acquired resistance; TFs, Transcription factors; TMV, Tobacco mosaic virus; VOCs, Volatile organic compounds.

Transmembrane signaling proteins couple extracytosolic sensors to cytosolic effectors. Here, we examine how binding of Mg²⁺ to the sensor domain of an E. coli two component histidine kinase (HK), PhoQ, modulates its cytoplasmic kinase domain. We use cysteine-crosslinking and reporter-gene assays to simultaneously and independently probe the signaling state of PhoQ's sensor and autokinase domains in a set of over 30 mutants. Strikingly, conservative single-site mutations distant from the sensor or catalytic site strongly influence PhoQ's ligand-sensitivity as well as the magnitude and direction of the signal. Data from 35 mutants are explained by a semi-empirical three-domain model in which the sensor, intervening HAMP, and catalytic domains can adopt kinase-promoting or inhibiting conformations that are in allosteric communication. The catalytic and sensor domains intrinsically favor a constitutively 'kinase-on' conformation, while the HAMP domain favors the 'off' state; when coupled, they create a bistable system responsive to physiological concentrations of Mg²⁺. Mutations alter signaling by locally modulating domain intrinsic equilibrium constants and interdomain couplings. Our model suggests signals transmit via interdomain allostery rather than propagation of a single concerted conformational change, explaining the diversity of signaling structural transitions observed in individual HK domains.

Keywords: E. coli; biochemistry; chemical biology.

Iron overload promotes the generation of reactive oxygen species (ROS). Pancreatic β-cells can counter oxidative stress through multiple anti-oxidant responses. Herein, RNA-sequencing was used to describe the expression profile of iron regulatory genes in human islets with or without diabetes. Functional experiments including siRNA silencing, qPCR, western blotting, cell viability, ELISA and RNA-sequencing were performed as means of identifying the genetic signature of the protective response following iron overload-induced stress in human islets and INS-1. FTH1 and FTL genes were highly expressed in human islets and INS-1 cells, while hepcidin (HAMP) was low. FXN, DMT1 and FTHL1 genes were differentially expressed in diabetic islets compared to control. Silencing of Hamp in INS-1 cells impaired insulin secretion and influenced the expression of β-cell key genes. RNA-sequencing analysis in iron overloaded INS-1 cells identified Id1 and Id3 as the top down-regulated genes, while Hmox1 was the top upregulated. Expression of ID1, ID3 and HMOX1 was validated at the protein level in INS-1 cells and human islets. Differentially expressed genes (DEGs) were enriched for TGF-β, regulating stem cells, ferroptosis, and HIF-1 signaling. Hmox1-silenced cells treated with FAC elevated the expression of Id1 and Id3 expression than untreated cells. Our findings suggest that HMOX1, ID1 and ID3 define the response mechanism against iron-overload-induced stress in β-cells.

Keywords: Diabetes; HMOX1, ID1; Human islets; ID3; INS-1 cells; Insulin; Iron-overload.

Crop damage by herbivorous insects remains a significant contributor to annual yield reductions. Following attack, maize (Zea mays) responds to Herbivore Associated Molecular Patterns (HAMPs) and Damage Associated Molecular Patterns (DAMPs), activating dynamic direct and indirect antiherbivore defense responses. To define underlying signaling processes, comparative analyses between Plant Elicitor Peptide (Pep) DAMPs and fatty acid-amino acid conjugate (FAC) HAMPs were conducted. RNA-seq based early transcriptional changes following Pep and FAC treatments revealed quantitative differences in the strength of response yet a high degree of qualitative similarity, providing evidence for shared signaling pathways. In further comparisons of FAC and Pep responses across diverse maize inbred lines, we identified Mo17 as part of a small subset of lines displaying selective FAC insensitivity. Genetic mapping for FAC sensitivity using the Intermated B73 x Mo17 population identified a single locus on chromosome 4 associated with FAC sensitivity. Pursuit of multiple fine-mapping approaches further narrowed the locus to 19 candidate genes. The top candidate gene identified, termed FAC SENSITIVITY ASSOCIATED (ZmFACS), encodes a leucine-rich repeat receptor-like kinase (LRR-RLK) that belongs to the same family as a rice receptor gene previously associated with the activation of induced responses to diverse Lepidoptera. Consistent with reduced sensitivity, ZmFACS expression was significantly lower in Mo17 as compared to B73. Transient heterologous expression of ZmFACS in Nicotiana benthamiana resulted in a significantly increased FAC-elicited response. Together, our results provide useful resources for studying early elicitor-induced antiherbivore responses in maize and approaches to discover gene candidates underlying HAMP sensitivity in grain crops.

Keywords: Zea mays; Peptide signalling; Plant-herbivore interactions; Quantitative genetics; Signalling and hormones; Terpenoids; Transcriptional regulation; Transcriptional response; Volatiles.

Background: Hereditary hemochromatosis (HH) is widely recognized and clinical manifestations of hemochromatosis-related (HFE-related) HH is well studied in European populations. Less is known about the clinical and laboratory characteristics of non-HFE related HH in Asian population. We aimed to explore the relationship between genotype and clinical phenotype in Chinese patients with non-HFE related hereditary hemochromatosis.

Methods: Peripheral blood samples and clinical data of patients with primary iron overload were collected from the China Registry of Genetic/Metabolic Liver Diseases. Sanger sequencing was performed in cases with primary iron overload, for 5 known HH related genes (HFE, HJV, HAMP, TFR2 and SLC40A1) and 2 novel iron homeostasis-related genes (DENND3 and SUGP2). The correlation of genotype and clinical phenotype in these patients was analyzed.

Results: Of the 32 patients with primary iron overload (23 were males and 9 were females), non-HFE variants were detected in 31 (31/32, 97%), including 8 pathogenic variants in HJV, 7 pathogenic variants in SLC40A1, 8 likely pathogenic variants in SUGP2 and 5 likely pathogenic variants in DENND3 cases. Among these 31 cases, 4 cases harbored homozygous variants, 2 cases harbored homozygous + heterozygous variants, 19 cases harbored heterozygous or combined heterozygous variants, and 6 cases harbored no any damaging variants. None of investigated cases carried damaging HAMP and TFR2 variants were found. 8 cases were classified as type 2A HH and 6 cases as type 4 HH, 10 cases as non-classical genotype, and 6 cases had no pathogenic variants from 31 cases. During the statistical analysis, we excluded one case (SLC40A1 IVS3 + 10delGTT + SUGP2 p. R639Q(homo)) with difficulty in grouping due to combined damaging variants. Cases with type 2A HH have an earlier age at diagnosis (p = 0.007). The iron index of cases in type 2A HH and type 4 HH was higher than that in other groups (p = 0.01). Arthropathy was relatively rare in all groups. None of cases with type 2A HH developed cirrhosis. Cirrhosis and diabetes are more prevalent in type 4 HH. The incidence of cirrhosis (p = 0.011), cardiac involvement (p = 0.042), diabetes (p = 0.035) and hypogonadism (p = 0.020) was statistically significant in the four groups. However, due to the limited sample size, the pairwise comparison showed no significant difference.

Conclusions: This is the first comprehensive analysis about the gene variant spectrum and phenotypic aspects of non-HFE HH in China. The results will be useful to the identification, diagnosis and management of HH in China.

Keywords: Genotype; Genotype–phenotype; Hereditary haemochromatosis (HH); Non-HFE.

Pyroptosis is the process of inflammatory cell death. The primary function of pyroptosis is to induce strong inflammatory responses that defend the host against microbe infection. Excessive pyroptosis, however, leads to several inflammatory diseases, including sepsis and autoimmune disorders. Pyroptosis can be canonical or noncanonical. Upon microbe infection, the canonical pathway responds to pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), while the noncanonical pathway responds to intracellular lipopolysaccharides (LPS) of Gram-negative bacteria. The last step of pyroptosis requires the cleavage of gasdermin D (GsdmD) at D275 (numbering after human GSDMD) into N- and C-termini by caspase 1 in the canonical pathway and caspase 4/5/11 (caspase 4/5 in humans, caspase 11 in mice) in the noncanonical pathway. Upon cleavage, the N-terminus of GsdmD (GsdmD-N) forms a transmembrane pore that releases cytokines such as IL-1β and IL-18 and disturbs the regulation of ions and water, eventually resulting in strong inflammation and cell death. Since GsdmD is the effector of pyroptosis, promising inhibitors of GsdmD have been developed for inflammatory diseases. This review will focus on the roles of GsdmD during pyroptosis and in diseases.

Keywords: 7DG, 7-desacetoxy-6,7-dehydrogedunin; ADRA2B, α-2B adrenergic receptor; AIM, absent in melanoma; ASC, associated speck-like protein; Ac-FLTD-CMK, acetyl-FLTD-chloromethylketone; BMDM, bone marrow-derived macrophages; CARD, caspase activation; CD, Crohn’s disease; CTM, Chinese traditional medicine; CTSG, cathepsin G; Caspase; DAMP, damage-associated molecular pattern; DFNA5, deafness autosomal dominant 5; DFNB59, deafness autosomal recessive type 59; DKD, diabetic kidney disease; DMF, dimethyl fumarate; Damage-associated molecular patterns (DAMPs); ELANE, neutrophil expressed elastase; ESCRT, endosomal sorting complexes required for transport; FADD, FAS-associated death domain; FDA, U.S. Food and Drug Administration; FIIND, function to find domain; FMF, familial Mediterranean fever; GI, gastrointestinal; GPX, glutathione peroxidase; Gasdermin; GsdmA/B/C/D/E, gasdermin A/B/C/D/E; HAMP, homeostasis altering molecular pattern; HIN, hematopoietic expression, interferon-inducible nature, and nuclear localization; HIV, human immunodeficiency virus; HMGB1, high mobility group protein B1; IBD, inflammatory bowel disease; IFN, interferon; ITPR1, inositol 1,4,5-trisphosphate receptor type 1; Inflammasome; Inflammation; LPS, lipopolysaccharide; LRR, leucine-rich repeat; MAP3K7, mitogen-activated protein kinase kinase kinase 7; MCC950, N-[[(1,2,3,5,6,7-hexahydro-s-indacen-4-yl)amino]carbonyl]-4-(1-hydroxy-1-methylethyl)-2-furansulfonamide; NAIP, NLR family apoptosis inhibitory protein; NBD, nucleotide-binding domain; NEK7, NIMA-related kinase 7; NET, neutrophil extracellular trap; NIK, NF-κB inducing kinase; NLR, NOD-like receptor; NLRP, NLR family pyrin domain containing; NSAID, non-steroidal anti-inflammatory drug; NSCLC, non-small cell lung cancer; NSP, neutrophil specific serine protease; PAMP, pathogen-associated molecular pattern; PKA, protein kinase A; PKN1/2, protein kinase1/2; PKR, protein kinase-R; PRR, pattern recognition receptors; PYD, pyrin domain; Pathogen-associated molecular patterns (PAMPs); Pyroptosis; ROS, reactive oxygen species; STING, stimulator of interferon genes; Sepsis; TLR, Toll-like receptor; UC, ulcerative colitis; cAMP, cyclic adenosine monophosphate; cGAS, cyclic GMP–AMP synthase; mtDNA, mitochondrial DNA.

Two component systems (TCSs) are a primary mechanism of signal sensing and response in bacteria. Systematic characterization of an entire TCS could provide a mechanistic understanding of these important signal transduction systems. Here, genetic selections were employed to dissect the molecular basis of signal transduction by the HitRS system that detects cell envelope stress in the pathogen Bacillus anthracis. Numerous point mutations were isolated within HitRS, 17 of which were in a 50-residue HAMP domain. Mutational analysis revealed the importance of hydrophobic interactions within the HAMP domain and highlighted its essentiality in TCS signaling. In addition, these data defined residues critical for activities intrinsic to HitRS, uncovered specific interactions among individual domains and between the two signaling proteins, and revealed that phosphotransfer is the rate-limiting step for signal transduction. Furthermore, this study establishes the use of unbiased genetic selections to study TCS signaling and provides a comprehensive mechanistic understanding of an entire TCS.

Objectives: Probenecid is an anion transport inhibitor, which, according to the connectivity map (CMap; a biological application database), interferes with hypoxia-induced gene expression changes in retinal vascular endothelial cells (ECs). Here, we investigated the influence of probenecid on retinal EC cytotoxicity and retinal neovascularization in a murine oxygen-induced retinopathy (OIR) model. Methods: The retinal EC growth rate in the presence of hypoxia-mimicking concentrations of cobalt chloride (CoCl₂) was determined using the thiazolyl blue tetrazolium bromide (MTT) assay and proliferating cell nuclear antigen (PCNA) expression. In OIR rats, probenecid was administered by intraperitoneal injection (i.p.) from postnatal day (P) 1 to P7. The concentrations of vitreous humor vascular endothelial growth factor (VEGF), hypoxia-inducible factor (HIF)-1α, and placental growth factor (PlGF) were determined by using the ELISA kit at P21. The amount of newly formed vascular lumen was evaluated by histopathological examination. Retinopathy and neovascularization were assessed by scoring isolectin B4 fluorescein-stained retinal flat mounts. Western blots for liver tissue HIF-1α and hepcidin (HAMP) were performed. Results: In vitro, probenecid led to the recession of the hypoxia-induced EC growth rate. In vivo, compared to the OIR retina, the upregulation of VEGF, HIF-1α, and PlGF in phase II retinopathy of prematurity (ROP) was inhibited by probenecid administration. Moreover, probenecid ameliorated neovascularization and resulted in significantly reduced relative leakage fluorescence signal intensity in fluorescein-stained retinal flat mounts (p < 0.05). Probenecid alleviated the liver overactivation of HAMP and downregulation of HIF-1α in OIR rats. Conclusions: This is the first demonstration that implies that probenecid might be a protective compound against retinal angiogenesis in OIR. These changes are accompanied with decreased hyperoxia-mediated hepcidin overproduction. Although the relevance of the results to ROP needs further research, these findings may help establish potential pharmacological targets based on the CMap database.

Keywords: CMAP; hepcidin (HAMP); oxygen-induced retinopathy (OIR); retinal neovascularization (RNV); retinopathy of prematurity (ROP); vascular endothelial cells (ECs).

Plant defense responses against insect herbivores are induced through wound-induced signaling and the specific perception of herbivore-associated molecular patterns (HAMPs). In addition, herbivores can deliver effectors that suppress plant immunity. Here we review plant immune recognition of HAMPs and effectors, and argue that these initial molecular interactions upon a plant-herbivore encounter mediate and structure effective resistance. While the number of distinct HAMPs and effectors from both chewing and piercing-sucking herbivores has expanded rapidly with omics-enabled approaches, paired receptors and targets in the host are still not well characterized. Herbivore-derived effectors may also be recognized as HAMPs depending on the host plant species, potentially through the evolution of novel immune receptor functions. We compile examples of HAMPs and effectors where natural variation between species may inform evolutionary patterns and mechanisms of plant-herbivore interactions. Finally, we discuss the combined effects of wounding and HAMP recognition, and review potential signaling hubs, which may integrate both sensing functions. Understanding the precise mechanisms for plant sensing of herbivores will be critical for engineering resistance in agriculture.

Keywords: FAC; GOX; HAMP; chewing; effector; herbivore; inceptin; piercing-sucking; wounding.

Patients with non-transfusion dependent thalassemia (NTDT) develop variable degrees of iron overload. Possible genes which may be implicated in causing iron overload are hepcidin (HAMP) and hemojuvelin (HFE). There is variable data assessing the role of c.-582Y A > G HAMP gene and H63D hotspot in HFE-1 gene in causing iron overload, while role of HFE-2 gene is undetermined. Twenty-five patients with NTDT (≥ 10 years) were assessed for iron overload. Genetic analysis for β-globin, α-globin, HAMP, HFE-2 and C282Y and H63D hotspots in HFE-1 genes was performed. T2*MRI demonstrated elevated LIC in 48% patients. No mutations were detected in HAMP gene or HFE-1 hotspots. Four single nucleotide variations (SNV) were detected in HFE-2 gene in 4 (20%) patients, including a novel SNV, p.Gln315Arg in 2 patients in heterozygous state. This is a likely pathogenic mutation; however, in heterozygous state, it did not lead to iron overload. HAMP and HFE-2 gene variations were infrequently seen in this pilot study, with no significant impact on iron overload. Presence of SNV p.Gln315Argin HFE-2 gene needs to be evaluated in larger sample sizes in our population to determine the incidence in homozygous state and its association with iron overload.

Supplementary information: The online version contains supplementary material available at 10.1007/s12288-021-01442-9.

Keywords: Ferritin; Hemojuvelin; Hepcidin; Iron overload; Liver iron concentration; Non-transfusion dependent thalassemia.