Transcription factors specificity protein and nuclear receptor 4A1 in pancreatic cancer

Specificity protein(Sp)transcription factors(TFs)Sp1,Sp3 and Sp4,and the orphan nuclear receptor 4A1(NR4A1)are highly expressed in pancreatic tumors and Sp1 is a negative prognostic factor for pancreatic cancer patient survival.Results of knockdown and overexpression of Sp1,Sp3 and Sp4 in pancreatic and other cancer lines show that these TFs are individually pro-oncogenic factors and loss of one Sp TF is not compensated by other members.NR4A1 is also a prooncogenic factor and both NR4A1 and Sp TFs exhibit similar functions in pancreatic cancer cells and regulate cell growth,survival,migration and invasion.There is also evidence that Sp TFs and NR4A1 regulate some of the same genes including survivin,epidermal growth factor receptor,PAX3-FOXO1,α5-andα6-integrins,β1-,β3-andβ4-integrins;this is due to NR4A1 acting as a cofactor and mediating NR4A1/Sp1/4-regulated gene expression through GC-rich gene promoter sites.Several studies show that drugs targeting Sp downregulation or NR4A1 antagonists are highly effective inhibitors of Sp/NR4A1-regulated pathways and genes in pancreatic and other cancer cells,and the triterpenoid celastrol is a novel dual-acting agent that targets both Sp TFs and NR4A1.

Effect of Marine Collagen Peptides on Markers of Metabolic Nuclear Receptors in Type 2 Diabetic Patients with/without Hypertension

Objective To explore Effects of marine collagen peptides （MCPs） on markers of metablic nuclear receptors, i.e peroxisome proliferator-activated receptor （PPARs）, liver X receptor （LXRs） and farnesoid X receptor （FXRs） in type 2 diabetic patients with/without hypertension. Method Study population consisted of 200 type 2 diabetic patients with/without hypertension and 50 healthy subjects, all of whom were randomly assigned to MCPs-treated diabetics （n=50）, placebo-treated diabetics （n=50）, MCPs-treated diabetics with hypertension （n=50）, placebo-treated diabetics with hypertension （n=50）, and healthy controls （n=50）. MCPs or placebo （water-soluble starch） were given daily before breakfast and bedtime over three months. Levels of free fatty acid, cytochrome P450, leptin, resistin, adiponectin, bradykinin, NO, and Prostacyclin were determined before intervention, and 1.5 months, and 3 months after intervention. Hypoglycemia and the endpoint events during the study were recorded and compared among the study groups. Result At the end of the study period, MCPs-treated patients showed marked improvement compared with patients receiving placebo. The protection exerted by MCPs seemed more profound in diabetics than in diabetics with hypertension. In particular, after MCPs intervention, levels of free fatty acid, hs-CRP, resistin, Prostacyclin decreased significantly in diabetics and tended to decrease in diabetic and hypertensive patients whereas levels of cytochrome P450, leptin, NO tended to decrease in diabetics with/without hypertension. Meanwhile, levels of adiponectin and bradykinin rose markedly in diabetics following MCPs administration. Conclusion MCPs could offer protection against diabetes and hypertension by affecting levels of molecules involved in diabetic and hypertensive pathogenesis. Regulation on metabolic nuclear receptors by MCPs may be the possible underlying mechanism for its observed effects in the study. Further study into its action may shed light on development of new drugs based on bioactive peptides from marine sources.

Potential role of nuclear receptor ligand all-trans retinoic acids in the treatment of fungal keratitis

·Fungal keratitis(FK) is a worldwide visual impairment disease. This infectious fungus initiates the primary innate immune response and, later the adaptive immune response. The inflammatory process is related to a variety of immune cells, including macrophages, helper T cells, neutrophils, dendritic cells, and Treg cells, and is associated with proinflammatory, chemotactic and regulatory cytokines. All-trans retinoic acids(ATRA)have diverse immunomodulatory actions in a number of inflammatory and autoimmune conditions. These retinoids regulate the transcriptional levels of target genes through the activation of nuclear receptors.Retinoic acid receptor α(RAR α), retinoic acid receptor γ(RAR γ), and retinoid X receptor α(RXR α) are expressed in the cornea and immune cells. This paper summarizes new findings regarding ATRA in immune and inflammatory diseases and analyzes the perspective application of ATRA in FK.

Nuclear receptors modulate inflammasomes in the pathophysiology and treatment of major depressive disorder

Major depressive disorder(MDD)is highly prevalent and is a significant cause of mortality and morbidity worldwide.Currently,conventional pharmacological treatments for MDD produce temporary remission in<50%of patients;therefore,there is an urgent need for a wider spectrum of novel antidepressants to target newly discovered underlying disease mechanisms.Accumulated evidence has shown that immune inflammation,particularly inflammasome activity,plays an important role in the pathophysiology of MDD.In this review,we summarize the evidence on nuclear receptors(NRs),such as glucocorticoid receptor,mineralocorticoid receptor,estrogen receptor,aryl hydrocarbon receptor,and peroxisome proliferator-activated receptor,in modulating the inflammasome activity and depression-associated behaviors.This review provides evidence from an endocrine perspective to understand the role of activated NRs in the pathophysiology of MDD,and to provide insight for the discovery of antidepressants with novel mechanisms for this devastating disorder.

Nuclear receptors and pathogenesis of pancreatic cancer

Pancreatic ductal adenocarcinoma(PDAC)is a devastating disease with a median overall survival time of5 mo and the five years survival less than 5%,a rate essentially unchanged over the course of the years.A well defined progression model of accumulation of genetic alterations ranging from single point mutations to gross chromosomal abnormalities has been introduced to describe the origin of this disease.However,due to the its subtle nature and concurring events PDAC cure remains elusive.Nuclear receptors(NR)are members of a large superfamily of evolutionarily conserved ligand-regulated DNA-binding transcription factors functionally involved in important cellular functions ranging from regulation of metabolism,to growth and development.Given the nature of their ligands,NR are very tempting drug targets and their pharmacological modulation has been widely exploited for the treatment of metabolic and inflammatory diseases.There are now clear evidences that both classical ligand-activated and orphan NR are involved in the pathogenesis of PDAC from its very early stages;nonetheless many aspects of their role are not fully understood.The purpose of this review is to highlight the striking connections that link peroxisome proliferator activated receptors,retinoic acid receptors,retinoid X receptor,androgen receptor,estrogen receptors and the orphan NR Nur,chicken ovalbumin upstream promoter transcription factorⅡand the liver receptor homologue-1 receptor to PDAC development,connections that could lead to the identification of novel therapies for this disease.

Expression of P450 and nuclear receptors in normal and end-stage Chinese livers

AIM:To investigate the expression of P450 enzyme genes by using end-stage liver disease samples and trimmed normal Chinese donor livers.METHODS:The end-stage liver disease samples[n=93,including hepatocellular carcinoma(HCC),peri-HCC tissue,hepatitis B virus cirrhosis,alcoholic cirrhosis,and severe cirrhosis]and trimmed normal Chinese donor livers(n=35)from The Institute of Organ Transplantation in Beijing,China.Total RNA was extracted,purified,and subjected to real-time RT-PCR analysis.RESULTS:For cytochrome P450 enzymes 1(CYP1)family,the expression of CYP1A2 was decreased 90%in HCC,80%in alcoholic cirrhosis,and 65%in severe cirrhosis.For CYP2 family,the expression of CAR was decreased 50%in HCC,but increased 50%in peri-HCC tissues.Similar decreases(about 50%)of CYP2B6,CYP2C9,CYP2C19,CYP2D6 and CYP2E1 were observed in HCC,as compared to peri-HCC tissues and normal livers.CYP2C19 were decreased in all end-stage liver diseases and CYP2E1 also decreased in alcoholic cirrhosis and severe cirrhosis.For CYP3 family,the expression of PXR was decreased 60%in HCC,together with decreases in CYP3A4,CYP3A5,and CYP3A7.In contrast,the expression of CYP3A7 was slightly increased in HBV cirrhosis.The expression of CYP4A11 was decreased85%in HCC,7%in alcoholic cirrhosis and severe liver cirrhosis,along with decreases in PPARα.The 93 endstage livers had much higher inter-individual variations in gene expression than 35 normal livers.CONCLUSION:The expression of CYP enzyme genes and corresponding nuclear receptors was generally decreased in end-stage liver diseases,and significant differences in gene expression were evident between peri-HCC and HCC.

Hepatic drug transporters and nuclear receptors:Regulation by therapeutic agents

The canalicular membrane represents the excretory pole of hepatocytes.Bile is an important route of elimination of potentially toxic endo-and xenobiotics(including drugs and toxins),mediated by the major canalicular transporters:multidrug resistance protein 1(MDR1, ABCB1),also known as P-glycoprotein,multidrug resistance-associated protein 2(MRP2,ABCC2),and the breast cancer resistance protein(BCRP,ABCG2).Their activities depend on regulation of expression and proper localization at the canalicular membrane,as regulated by transcriptional and post-transcriptional events,respectively.At transcriptional level,specific nuclear receptors(NR)s modulated by ligands,co-activators and co-repressors,mediate the physiological requirements of these transporters.This complex system is also responsible for alterations occurring in specific liver pathologies.We briefly describe the major ClassⅡNRs, pregnane X receptor(PXR)and constitutive androstane receptor(CAR),and their role in regulating expression of multidrug resistance proteins.Several therapeutic agents regulate the expression of relevant drug transporters through activation/inactivation of these NRs.We provide some representative examples of the action of therapeutic agents modulating liver drug transporters, which in addition,involve CAR or PXR as mediators.

Role of nuclear receptors in breast cancer stem cells

The recapitulation of primary tumour heterogenity and the existence of a minor sub-population of cancer cells,capable of initiating tumour growth in xenografts on serial passages, led to the hypothesis that cancer stem cells(CSCs) exist. CSCs are present in many tumours, among which is breast cancer. Breast CSCs(BCSCs) are likely to sustain the growth of the primary tumour mass, as wellas to be responsible for disease relapse and metastatic spreading. Consequently, BCSCs represent the most significant target for new drugs in breast cancer therapy. Both the hypoxic condition in BCSCs biology and proinflammatory cytokine network has gained increasing importance in the recent past. Breast stromal cells are crucial components of the tumours milieu and are a major source of inflammatory mediators. Recently, the antiinflammatory role of some nuclear receptors ligands has emerged in several diseases, including breast cancer. Therefore, the use of nuclear receptors ligands may be a valid strategy to inhibit BCSCs viability and consequently breast cancer growth and disease relapse.

Expression and role of nuclear receptor coregulators in colorectal cancer

Colorectal cancer(CRC) is one of the most common human cancers and the cause of about 700000 deaths per year worldwide. Deregulation of the WNT/β-catenin pathway is a key event in CRC initiation. This pathway interacts with other nuclear signaling pathways, including members of the nuclear receptor superfamily and their transcription coregulators. In this review, we provide an overview of the literature dealing with the main coactivators(NCo A-1 to 3, NCo A-6, PGC1-α, p300, CREBBP and MED1) and corepressors(N-Co R1 and 2, NRIP1 and MTA1) of nuclear receptors and summarize their links with the WNT/β-catenin signaling cascade, their expression in CRC and their role in intestinal physiopathology.

Analysis of ileal sodium/bile acid cotransporter and related nuclear receptor genes in a family with multiple cases of idiopathic bile acid malabsorption

The etiology of most cases of idiopathic bile acid malabsorption (IBAM) is unknown. In this study, a Swedish family with bile acid malabsorption in three consecutive generations was screened for mutations in the ileal apical sodium-bile acid cotransporter gene (ASBT; gene symbol, SLC10A2) and in the genes for several of the nuclear receptors known to be important for ASBT expression: the farnesoid X receptor (FXR) and peroxisome proliferator activated receptor alpha (PPARa). The patients presented with a clinical history of idiopathic chronic watery diarrhea, which was responsive to cholestyramine treatment and consistent with IBAM. Bile acid absorption was determined using 75Se-homocholic acid taurine (SeHCAT); bile acid synthesis was estimated by measuring the plasma levels of 7a-hydroxy-4-cholesten-3-one (C4). The ASBT, FXR, and PPARa genes in the affected and unaffected family members were analyzed using single stranded conformation polymorphism (SSCP), denaturing HPLC, and direct sequencing. No ASBT mutations were identified and the ASBT gene did not segregate withthe bile acid malabsorption phenotype. Similarly, no mutations or polymorphisms were identified in the FXR or PPARa genes associated with the bile acid malabsorption phenotype. These studies indicate that the intestinal bile acid malabsorption in these patients cannot be attributed to defects in ASBT. In the absence of apparent ileal disease, alternative explanations such as accelerated transit through the small intestine may be responsible for the IBAM.

Biological effect of expression of exogenous human nuclear receptor hLRH-1 in SW480 cells and its molecular mechanism

Objective: To explore the possible biological function of human nuclear receptor hLRH-1 in tumorigenesis and progress of colon cancer. Methods: Plasmids pcDNA3-hLRH-1 were introduced into SW480 cells via lipofectamine. The expression of mRNA and protein of exogenous hLRH-1 were detected by RT-PCR and western blotting, respectively. MTT assay was carried out to survey the proliferation of SW480 cells with overexpression of hLRH-1. Meanwhile, the expression of proliferation-related genes cyclin E1 and cyclin D1, and apoptosis-related genes PTEN and Rb1, were analyzed by real- time RT-PCR. Results: The proliferation of SW480 cells was promoted under the condition of overexpression of hLRH-1. The expression of cyclin E1 was up-regulated significantly, while that of PTEN and Rb1 were down-regulated in SW480 cells with overexpressed hLRH-1. Conclusion: The expression of exogenous hLRH-1 in SW480 cells induced the proliferation resulting form up-regulation of cyclin E1, as well as participated in the regulation of apoptosis via influencing the expression of PTEN and Rb1.

Expression change of nuclear receptor corepressor (NCoR) in androgen independence prostate cancer and its clinical significance

Objective:To explore the expression of nuclear receptor corepressor (NCoR) in androgen independence prostate cancer (AIPC) and its clinical significance. Methods:The expression of NCoR and androgen receptor (AR) in prostatic tissues, from 15 cases with AIPC, 20 cases with androgen dependence prostate cancer (ADPC) and 20 cases with benign prostatic hyperplasia (BPH), was detected by immunohistochemistry respectively. Results:The expression of NCoR was observed mainly in the nucleus and slightly in the nucleus. The positive cell percentage of NCoR in AIPC was significantly lower than that in ADPC and BPH (P<0.01). The NCoR expression was significantly lower in low differentiation prostate cancer (Pca) than that in high differentiation Pca (P<0.05). The rate of NCoR expression was significantly higher in low stage Pca than that in high stage Pca (P<0.05). AR, expressing in the nucleus, was found to be negative in one case of AIPC, while was strongly expressed in other cases of AIPC, and all cases of ADPC and BPH. Conclusion: The transition to AIPC of Pca may be correlated with the decrease of NCoR protein.

Diurnal Variation of Nuclear Receptors in Mice with or without Fasting

Nuclear receptors such as pregnane X receptor (PXR) and constitutive androstane receptor (CAR) regulate the transcription of transporter and cytochrome P450 (CYP). The diurnal variation was observed in some transporters regulated by nuclear receptors. We investigated whether diurnal variation in PXR and CAR exists in mice. We also examined the effect of food intake on the diurnal rhythm of hepatic PXR and CAR using fed and fasted mice. In liver and small intestine of fed mice, the mRNA levels of PXR and CAR were unchanged between 7:00 AM and 7:00 PM. In contrast to fed mice, fasting mice partly exhibited the diurnal variation in PXR, not in CAR. The mRNA levels of PXR at 7:00 AM were significantly higher than that those at 7:00 PM in liver of fasting mice. These results indicated the different effects of fasting in mice on diurnal variation of PXR in each tissue.

Nuclear receptor coactivator 6 is a critical regulator of NLRP3 inflammasome activation and gouty arthritis

Transcriptional coactivators regulate the rate of gene expression in the nucleus.Nuclear receptor coactivator 6(NCOA6),a coactivator,has been implicated in embryonic development,metabolism,and cancer pathogenesis,but its role in innate immunity and inflammatory diseases remains unclear.Here,we demonstrated that NCOA6 was expressed in monocytes and macrophages and that its level was increased under proinflammatory conditions.Unexpectedly,nuclear NCOA6 was found to translocate to the cytoplasm in activated monocytes and then become incorporated into the inflammasome with NLRP3 and ASC,forming cytoplasmic specks.Mechanistically,NCOA6 associated with the ATP hydrolysis motifs in the NACHT domain of NLRP3,promoting the oligomerization of NLRP3 and ASC and thereby instigating the production of IL-1βand active caspase-1.Of note,Ncoa6 deficiency markedly inhibited NLRP3 hyperactivation caused by the Nlrp3^(R258W) gain-of-function mutation in macrophages.Genetic ablation of Ncoa6 substantially attenuated the severity of two NLRP3-dependent diseases,folic-induced acute tubular necrosis and crystal-induced arthritis,in mice.Consistent with these findings,NCOA6 was highly expressed in macrophages derived from gout patients,and NCOA6-positive macrophages were significantly enriched in gout macrophages according to the transcriptome profiling results.Conclusively,NCOA6 is a critical regulator of NLRP3 inflammasome activation and is therefore a promising target for NLRP3-dependent diseases,including gout.

Mechanism of acupuncture in attenuating cerebral ischaemia-reperfusion injury based on nuclear receptor coactivator 4 mediated ferritinophagy

OBJECTIVE:To explore the effect of acupuncture treatment on cerebral ischaemia-reperfusion injury(CIRI)and reveal the underlying mechanism of the effect based on nuclear receptor coactivator 4(NCOA4)mediated ferritinophagy.METHODS:Sprague-Dawley male rats were divided into four groups:the sham group,model group,acupuncture group,and sham acupuncture group.After 2 h of middle cerebral artery occlusion(MCAO),reperfusion was performed for 24 h to induce CIRI.The rats were treated with acupuncture at the Neiguan(PC6)and Shuigou(GV26)acupoints.Their neurological function was evaluated by taking their Bederson scores at 2 h after ischaemia and 24 h after reperfusion.Triphenyltetrazolium chloride staining was applied to assess the cerebral infarct volume at 24 h after reperfusion.The malondialdehyde(MDA)and ferrous iron(Fe^(2+))levels were observed after 24 h of reperfusion using an assay kit.Western blotting was performed to detect the expression of NCOA4 and ferritin heavy chain 1(FTH1)at 24 h after reperfusion.Moreover,the colocalization of ferritin with neurons,NCOA4 with microtubule-associated protein 1 light chain 3(LC3),and NCOA4 with ferritin was visualized using immunofluorescence staining.RESULTS:Acupuncture significantly improved neurological function and decreased cerebral infarct volume in the acupuncture group.Following CIRI,the expression of NCOA4,LC3 and FTH1 was increased,which enhanced ferritinophagy and induced an inappropriate accumulation of Fe^(2+)and MDA in the ischaemic brain.However,acupuncture dramatically downregulated the expression of NCOA4,LC3 and FTH1,inhibited the overactivation of ferritinophagy,and decreased the levels of MDA and Fe^(2+).CONCLUSIONS:Acupuncture can inhibit NCOA4-mediated ferritinophagy and protect neurons against CIRI in a rat model.

Targeting nuclear receptors for NASH/MASH:From bench to bedside

The onset of metabolic dysfunction-associated steatohepatitis(MASH)or non-alcoholic steatohepatitis(NASH)represents a tipping point leading to liver injury and subsequent hepatic complications in the natural progression of what is now termed metabolic dysfunction-associated steatotic liver diseases(MASLD),formerly known as non-alcoholic fatty liver disease(NAFLD).With no pharmacological treat-ment currently available for MASH/NASH,the race is on to develop drugs targeting multiple facets of hepatic metabolism,inflammation,and pro-fibrotic events,which are major drivers of MASH.Nuclear receptors(NRs)regulate genomic transcription upon binding to lipophilic ligands and govern multiple aspects of liver metabolism and inflammation.Ligands of NRs may include hormones,lipids,bile acids,and synthetic ligands,which upon binding to NRs regulate the transcriptional activities of target genes.NR ligands are presently the most promising drug candidates expected to receive approval from the United States Food and Drug Administration as a pharmacological treatment for MASH.This review aims to cover the current understanding of NRs,including nuclear hormone receptors,non-steroid hormone receptors,circadian NRs,and orphan NRs,which are currently undergoing clinical trials for MASH treatment,along with NRs that have shown promising results in preclinical studies.

Aryl hydrocarbon receptor nuclear translocator 2 as a prognostic biomarker and immunotherapeutic indicator for clear cell renal cell carcinoma

Background:In many cancer types,aryl hydrocarbon receptor nuclear translocator 2(ARNT2)has been found to be associated with tumor cell proliferation and prognosis.However,the role of ARNT2 in clear cell renal cell carcinoma(ccRCC)has not been completely elucidated.In this study,the potential role of ARNT2 in ccRCC development was characterized.Methods:A pan-cancer dataset(TCGA-TARGET-GTEx)was accessed from UCSC Xena Data Browser.ARNT2 expression in normal and tumor samples was compared.Univariate Cox regression was performed to evaluate the prognostic value of ARNT2.Single sample gene set enrichment analysis(ssGSEA)was used to estimate the enrichment of functional pathways and gene signatures.CIBERSORT and ESTIMATE methods evaluated the immune infiltration.The ARNT2 expression was determined in ccRCC tissue and cell lines using RT-qPCR and Western blot.Results:ARNT2 expression was significantly dysregulated in 23 out of 30 cancer types.Pan-cancer data revealed a strong correlation between ARNT2 expression and immune modulators,immune cell infiltration,and genomic alternations.In ccRCC patients,the low-ARNT2 expression group had higher immune infiltration,CD8 T cells,and programmed cell death ligand 1 expression,as well as higher enrichment score of immunotherapeutic predictors than those in the high-ARNT2 expression group.Low-ARNT2 expression group was more responsive to immunotherapy.Moreover,low ARNT2 expression was observed in ccRCC tissue and cell lines.Conclusions:Dysregulated ARNT2 expression is involved in cancer development and the modulation of the immune microenvironment.ARNT2 can be potentially used as a prognostic indicator and an immunotherapeutic indicator for ccRCC.

Understanding the physiological functions of the host xenobiotic-sensing nuclear receptors PXR and CAR on the gut microbiome using genetically modified mice

Pharmacological activation of the xenobiotic-sensing nuclear receptors pregnane X receptor(PXR) and constitutive androstane receptor(CAR) is well-known to increase drug metabolism and reduce inflammation. Little is known regarding their physiological functions on the gut microbiome. In this study, we discovered bivalent hormetic functions of PXR/CAR modulating the richness of the gut microbiome using genetically engineered mice. The absence of PXR or CAR increased microbial richness, and absence of both receptors synergistically increased microbial richness. PXR and CAR deficiency increased the pro-inflammatory bacteria Helicobacteraceae and Helicobacter. Deficiency in both PXR and CAR increased the relative abundance of Lactobacillus, which has bile salt hydrolase activity, corresponding to decreased primary taurine-conjugated bile acids(BAs) in feces, which may lead to higher internal burden of taurine and unconjugated BAs, both of which are linked to inflammation, oxidative stress, and cytotoxicity. The basal effect of PXR/CAR on the gut microbiome was distinct from pharmacological and toxicological activation of these receptors. Common PXR/CAR-targeted bacteria were identified, the majority of which were suppressed by these receptors. h PXR-TG mice had a distinct microbial profile as compared to wild-type mice. This study is the first to unveil the basal functions of PXR and CAR on the gut microbiome.

Screening of agonistic activities against four nuclear receptors in wastewater treatment plants in Japan using a yeast two-hybrid assay

To assess the potential endocrine disruptive effects through multiple nuclear receptors （NRs）, especially non-steroidal NRs, in municipal wastewater, we examined the agonistic activities on four NRs （estrogen receptor α, thyroid hormone receptor α, retinoic acid receptor ct and retinoid X receptor α） of untreated and treated wastewater from municipal wastewater treatment plants （WWTPs） in Japan using a yeast two-hybrid assay. Investigation of the influent and effluent of seven WWTPs revealed that agonistic activities against steroidal and non-steroidal NRs were always detected in the influents and partially remained in the effluents. Further investigation of four WWTPs employing conventional activated sludge, pseudo-anoxic-oxic, anoxic-oxic and anaerobic-anoxic-oxic processes revealed that the ability to reduce the agonistic activity against each of the four NRs varies depending on the treatment process. These results indicated that municipal wastewater in Japan commonly contains endocrine disrupting chemicals that exert agonistic activities on steroidal and non-steroidal NRs, and that some of these chemicals are released into the natural aquatic environment. Although the results obtained in yeast assays suggested that measured levels of non-steroidal NR agonists in the effluent of WWTPs were not likely to cause any biological effect, further study is required to assess their possible risks in detail.

Endocrine pheromones couple fat rationing to dauer diapause through HNF4αnuclear receptors

Developmental diapause is a widespread strategy for animals to survive seasonal starvation and environmental harshness.Diapaused animals often ration body fat to generate a basal level of energy for enduring survival.How diapause and fat rationing are coupled,however,is poorly understood.The nematode Caenorhabditis elegans excretes pheromones to the environment to induce a diapause form called dauer larva.Through saturated forward genetic screens and CRISPR knockout,we found that dauer pheromones feed back to repress the transcription of ACOX-3,MAOC-1,DHS-28,DAF-22(peroxisomalβ-oxidation enzymes dually involved in pheromone synthesis and fat burning),ALH-4(aldehyde dehydrogenase for pheromone synthesis),PRX-10 and PRX-11(peroxisome assembly and proliferation factors).Dysfunction of these pheromone enzymes and factors relieves the repression.Surprisingly,transcription is repressed not by pheromones excreted but by pheromones endogenous to each animal.The endogenous pheromones regulate the nuclear translocation of HNF4αfamily nuclear receptor NHR-79 and its co-receptor NHR-49,and,repress transcription through the two receptors.The feedback repression maintains pheromone homeostasis,increases fat storage,decreases fat burning,and prolongs dauer lifespan.Thus,the exocrine dauer pheromones possess an unexpected endocrine function to mediate a peroxisome-nucleus crosstalk,coupling dauer diapause to fat rationing.