Rab18 maintains homeostasis of subcutaneous adipose tissue to prevent obesity-induced metabolic disorders

Metabolically healthy obesity refers to obese individuals who do not develop metabolic disorders.These people store fat in subcutaneous adipose tissue(SAT)rather than in visceral adipose tissue(VAT).However,the molecules participating in this specific scenario remain elusive.Rab18,a lipid droplet(LD)-associated protein,mediates the contact between the endoplasmic reticulum(ER)and LDs to facilitate LD growth and maturation.In the present study,we show that the protein level of Rab18 is specifically upregulated in the SAT of obese people and mice.Rab18 adipocyte-specific knockout(Rab18 AKO)mice had a decreased volume ratio of SAT to VAT compared with wildtype mice.When subjected to high-fat diet(HFD),Rab18 AKO mice had increased ER stress and inflammation,reduced adiponectin,and decreased triacylglycerol(TAG)accumulation in SAT.In contrast,TAG accumulation in VAT,brown adipose tissue(BAT)or liver of Rab18AKO mice had a moderate increase without ER stress stimulation.Rab18 AKO mice developed insulin resistance and systematic inflammation.Rab18 AKO mice maintained body temperature in response to acute and chronic cold induction with a thermogenic SAT,similar to the counterpart mice.Furthermore,Rab18-deficient 3T3-L1 adipocytes were more prone to palmitate-induced ER stress,indicating the involvement of Rab18 in alleviating lipid toxicity.Rab18 AKO mice provide a good animal model to investigate metabolic disorders such as impaired SAT.In conclusion,our studies reveal that Rab18 is a key and specific regulator that maintains the proper functions of SAT by alleviating lipid-induced ER stress.

Gene-knockout by iSTOP enables rapid reproductive disease modeling and phenotyping in germ cells of the founder generation

Cytosine base editing achieves C·G-to-T·A substitutions and can convert four codons(CAA/CAG/CGA/TGG)into STOP-codons(induction of STOP-codons,iSTOP)to knock out genes with reduced mosaicism.iSTOP enables direct phenotyping in founders’somatic cells,but it remains unknown whether this works in founders’germ cells so as to rapidly reveal novel genes for fertility.Here,we initially establish that iSTOP in mouse zygotes enables functional characterization of known genes in founders’germ cells:Cfap43-iSTOP male founders manifest expected sperm features resembling human“multiple morphological abnormalities of the flagella”syndrome(i.e.,MMAF-like features),while oocytes of Zp3-iSTOP female founders have no zona pellucida.We further illustrate iSTOP’s utility for dissecting the functions of unknown genes with Ccdc183,observing MMAF-like features and male infertility in Ccdc183-iSTOP founders,phenotypes concordant with those of Ccdc183-KO offspring.We ultimately establish that CCDC183 is essential for sperm morphogenesis through regulating the assembly of outer dynein arms and participating in the intra-flagellar transport.Our study demonstrates iSTOP as an efficient tool for direct reproductive disease modeling and phenotyping in germ cells of the founder generation,and rapidly reveals the essentiality of Ccdc183 in fertility,thus providing a time-saving approach for validating genetic defects(like nonsense mutations)for human infertility.

Comprehensive analysis of mitochondrial dynamic-related genes on their functions and prognostic values for glioblastoma multiforme

Glioblastoma multiforme(GBM)is the most malignant intracranial tumor in adults and its unique pathology leads to limited therapeutic benefits.1,2 Mitochondrial fusion and fission play an important role in carcinogenesis;fragmented mitochondria promote tumor cell proliferation and prolonged mitochondria lead to tumor cell apoptosis.3 Therefore,profiling the function and prognostic value of mitochondrial dynamics-related genes(MDRGs)is of great interest for GBM precision treatment.Here we focused on the expression,function,and genetic alterations of MDRGs and identified new DNA methylation sites being significantly associated with the survival of GBM patients using available data in public databases.

Downregulated nuclear lncRNA NRON inhibits SHP2/Wnt/β-catenin signaling and cardiomyocyte differentiation during the development of Tetralogy of Fallot

Tetralogy of Fallot(TOF)is the most common cyanotic congenital heart disease and the incidence of late cardiac death in long-term survivors continues to increase.1 So,there is an urgent need to explore the etiology and pathogenesis of TOF.The precise cause of TOF is currently unclear,and exploration of the pathogenesis has focused increasingly in recent years on the roles of noncoding gene products,especially long noncoding RNAs(lncRNAs).

Exercise-induced microbial changes in preventing type 2 diabetes

The metabolic benefits associated with long-term physical activity are well appreciated and growing evidence suggests that it involves the gut microbiota.Here we re-evaluated the link between exercise-induced microbial changes and those associated with prediabetes and diabetes.We found that the relative abundances of substantial amounts of diabetes-associated metagenomic species associated negatively with physical fitness in a Chinese athlete students cohort.We additionally showed that those microbial changes correlated more with handgrip strength,a simple but valuable biomarker suggestive of the diabetes states,than maximum oxygen intake,one of the key surrogates for endurance training.Moreover,the causal relationships among exercise,risks for diabetes,and gut microbiota were explored based on mediation analysis.We propose that the protective roles of exercise against type 2 diabetes are mediated,at least partly,by the gut microbiota.

Coiled-coil domain-containing 38 is required for acrosome biogenesis and fibrous sheath assembly in mice

During spermiogenesis,haploid spermatids undergo dramatic morphological changes to form slender sperm flagella and cap-like acrosomes,which are required for successful fertilization.Severe deformities in flagella cause a male infertility syndrome,multiple morphological abnormalities of the flagella(MMAF),while acrosomal hypoplasia in some cases leads to sub-optimal embryonic developmental potential.However,evidence regarding the occurrence of acrosomal hypoplasia in MMAF is limited.Here,we report the generation of base-edited mice knocked out for coiled-coil domain-containing 38(Ccdc38)via inducing a nonsense mutation and find that the males are infertile.The Ccdc38-KO sperm display acrosomal hypoplasia and typical MMAF phenotypes.We find that the acrosomal membrane is loosely anchored to the nucleus and fibrous sheaths are disorganized in Ccdc38-KO sperm.Further analyses reveal that Ccdc38 knockout causes a decreased level of TEKT3,a protein associated with acrosome biogenesis,in testes and an aberrant distribution of TEKT3 in sperm.We finally show that intracytoplasmic sperm injection overcomes Ccdc38-related infertility.Our study thus reveals a previously unknown role for CCDC38 in acrosome biogenesis and provides additional evidence for the occurrence of acrosomal hypoplasia in MMAF.

Amino acids TORC(talk)to anabolism through uncharged tRNA

Anabolism is essential for proliferation as well as to replenish dysfunctional macromolecules in cells.Due to that both substantial building blocks and energy are required for anabolism,cells must double check whether these prerequisites are met before deciding to start anabolism.Amino acids are building blocks of protein synthesis,their sufficiency in cells is closely monitored by several mechanisms,which all are linked to protein synthesis.

IMAGGS: a radiogenomic framework for identifying multi-way associations in breast cancer subtypes

Investigating correlations between radiomic and genomic profiling in breast cancer(BC)molecular subtypes is crucial for understanding disease mechanisms and providing personalized treatment.We present a well-designed radiogenomic framework image–gene–gene set(IMAGGS),which detects multi-way associations in BC subtypes by integrating radiomic and genomic features.Our dataset consists of 721 patients,each of whom has 12 ultrasound(US)images captured from different angles and gene mutation data.To better characterize tumor traits,12 multi-angle US images are fused using two distinct strategies.Then,we analyze complex many-to-many associations between phenotypic and genotypic features using a machine learning algorithm,deviating from the prevalent one-to-one relationship pattern observed in previous studies.Key radiomic and genomic features are screened using these associations.In addition,gene set enrichment analysis is performed to investigate the joint effects of gene sets and delve deeper into the biological functions of BC subtypes.We further validate the feasibility of IMAGGS in a glioblastoma multiforme dataset to demonstrate the scalability of IMAGGS across different modalities and diseases.Taken together,IMAGGS provides a comprehensive characterization for diseases by associating imaging,genes,and gene sets,paving the way for biological interpretation of radiomics and development of targeted therapy.

Deamidation enables pathogenic SMAD6 variants to activate the BMP signaling pathway

The BMP signaling pathway plays a crucial role in regulating early embryonic development and tissue homeostasis.SMAD6 encodes a negative regulator of BMP,and rare variants of SMAD6 are recurrently found in individuals with birth defects.However,we observed that a subset of rare pathogenic variants of SMAD6 consistently exhibited positive regulatory effects instead of the initial negative effects on the BMP signaling pathway.We sought to determine whether these SMAD6 variants have common pathogenic mechanisms.Here,we showed that pathogenic SMAD6 variants accompanying this functional reversal exhibit similar increases in deamidation.Mechanistically,increased deamidation of SMAD6 variants promotes the accumulation of the BMP receptor BMPR1A and the formation of new complexes,both of which lead to BMP signaling pathway activation.Specifically,two residues,N262 and N404,in SMAD6 were identified as the crucial sites of deamidation,which was catalyzed primarily by glutamine-fructose-6-phosphate transaminase 2(GFPT2).Additionally,treatment of cells harboring SMAD6 variants with a deamidase inhibitor restored the inhibitory effect of SMAD6 on the BMP signaling pathway.Conversely,when wild-type SMAD6 was manually simulated to mimic the deamidated state,the reversed function of activating BMP signaling was reproduced.Taken together,these findings show that deamidation of SMAD6 plays a crucial role in the functional reversal of BMP signaling activity,which can be induced by a subset of various SMAD6 variants.Our study reveals a common pathogenic mechanism shared by these variants and provides a potential strategy for preventing birth defects through deamidation regulation,which might prevent the off-target effects of gene editing.

Endorepellin和neurexin互作促进神经上皮细胞自噬并维持正常神经管发育

Heparan sulfate proteoglycan 2(HSPG2)gene encodes the matrix protein Perlecan,and genetic inactivation of this gene creates mice that are embryonic lethal with severe neural tube defects(NTDs).We discovered rare genetic variants of HSPG2 in 10%cases compared to only 4%in controls among a cohort of 369 NTDs.Endorepellin,a peptide cleaved from the domain V of Perlecan,is known to promote angiogenesis and autophagy in endothelial cells.The roles of enderepellin in neurodevelopment remain unclear so far.Our study revealed that endorepellin can migrate to the neuroepithelial cells and then be recognized and bind with the neuroepithelia receptor neurexin in vivo.Through the endocytic pathway,the interaction of endorepellin and neurexin physiologically triggers autophagy and appropriately modulates the differentiation of neural stem cells into neurons as a blocker,which is necessary for normal neural tube closure.We created knock-in(KI)mouse models with human-derived HSPG2 variants,using sperm-like stem cells that had been genetically edited by CRISPR/Cas9.We realized that any HSPG2 variants that affected the function of endorepellin were considered pathogenic causal variants for human NTDs given that the severe NTD phenotypes exhibited by these KI embryos occurred in a significantly higher response frequency compared to wildtype embryos.Our study provides a paradigm for effectively confirming pathogenic mutations in other genetic diseases.Furthermore,we demonstrated that using autophagy inhibitors at a cellular level can repress neuronal differentiation.Therefore,autophagy agonists may prevent NTDs resulting from failed autophagy maintenance and neuronal over-differentiation caused by deleterious endorepellin variants.

A mutation in TBXT causes congenital vertebral malformations in humans and mice

T-box transcription factor T(TBXT;T)is required for mesodermal formation and axial skeletal development.Although it has been extensively studied in various model organisms,human congenital vertebral malformations(CVMs)involving T are not well established.Here,we report a family with 15 CVM patients distributed across 4 generations.All affected individuals carry a heterozygous mutation,T c.596A>G(p.Q199R),which is not found in unaffected family members,indicating co-segregation of the genotype and phenotype.In vitro assays show that T p.Q199R increases the nucleocytoplasmic ratio and enhances its DNA-binding affinity,but reduces its transcriptional activity compared to the wild-type.To determine the pathogenicity of this mutation in vivo,we generated a Q199R knock-in mouse model that recapitulates the human CVM phenotype.Most heterozygous Q199R mice show subtle kinked or shortened tails,while homozygous mice exhibit tail filaments and severe vertebral deformities.Overall,we show that the Q199R mutation in T causes CVM in humans and mice,providing previously unreported evidence supporting the function of T in the genetic etiology of human CVM.

基因组结构变异研究的前瞻性及临床应用

The challenges and breakthroughs in human genetics can largely depend on the depth of exploring the missing heritability[1]and understanding of genetic variants,which enabled scientists to better elucidate the underlying causes of diseases and apply this knowledge in clinical settings.Human genomes differ from one individual to another in the form of single nucleotide variants(SNVs),small insertions and deletions(indels)(<50 base pairs(bp)),and structural variants(SVs)[2].

Follicle stimulating hormone controls granulosa cell glutamine synthesis to regulate ovulation

Polycystic ovary syndrome(PCOS)is the leading cause of anovulatory infertility.Inadequate understanding of the ovulation drivers hinders PCOS intervention.Herein,we report that follicle stimulating hormone(FSH)controls follicular fluid(FF)glutamine levels to determine ovulation.Murine ovulation starts from FF-exposing granulosa cell(GC)apoptosis.FF glutamine,which decreases in pre-ovulation porcine FF,elevates in PCOS patients FF.High-glutamine chow to elevate FF glutamine inhibits mouse GC apoptosis and induces hormonal,metabolic,and morphologic PCOS traits.Mechanistically,follicle-development-driving FSH promotes GC glutamine synthesis to elevate FF glutamine,which maintain follicle wall integrity by inhibiting GC apoptosis through inactivating ASK1-JNK apoptotic pathway.FSH and glutamine inhibit the rapture of cultured murine follicles.Glutamine removal or ASK1-JNK pathway activation with metformin or AT-101 reversed PCOS traits in PCOS models that are induced with either glutamine or EsR1-KO.These suggest that glutamine,FSH,and ASK1-JNK pathway are targetable to alleviate PCOS.

MRE11 lactylation:a linker between Warburg effect and DNA repair

Lysine lactylation is a recently discovered post-translational modification with emerging roles in both physiology and disease.A recent study published in Cell shows that lactate-induced lactylation of the homologous recombination(HR)protein meiotic recombination 11 results in HR hyperactivation and chemoresistance in cancer cells,establishing a previously unrecognized link between cellular metabolism and deoxyribonucleic acid(DNA)damage repair and providing new insights into how altered glucose metabolism can impact DNA damage response in cancer.

PITPNC1 promotes the thermogenesis of brown adipose tissue under acute cold exposure

Brown adipose tissue (BAT) plays an essential role in non-shivering thermogenesis. The phosphatidylinositol transfer protein, cytoplasmic 1 (PITPNC1) is identified as a lipid transporter that reciprocally transfers phospholipids between intracellular membrane structures. However, the physiological significance of PITPNC1 and its regulatory mechanism remain unclear. Here, we demonstrate that PITPNC1 is a key player in thermogenesis of BAT. While Pitpnc1^(−/−) mice do not differ with wildtype mice in body weight and insulin sensitivity on either chow or high-fat diet, they develop hypothermia when subjected to acute cold exposure at 4℃. The Pitpnc1^(−/−) brown adipocytes exhibit defective β-oxidation and abnormal thermogenesis-related metabolism pathways in mitochondria. The deficiency of lipid mobilization in Pitpnc1^(−/−) brown adipocytes might be the result of excessive accumulation of phosphatidylcholine and a reduction of phosphatidic acid. Our findings have uncovered significant roles of PITPNC1 in mitochondrial phospholipid homeostasis and BAT thermogenesis.

Master microRNA-222 regulates cardiac microRNA maturation and triggers Tetralogy of Fallot

Dear Editor,Tetralogy of Fallot(TOF)is the most common complex congenital heart disease.Besides gene mutations and copy number variants,altered protein function induced by posttranscriptional or translational regulation also contributes to the onset of TOF.1 MiRNAs are short noncoding RNAs that bind to the 3’-UTR of target mRNAs to repress protein production.However,the causal link between miRNAs and TOF and the underlying mechanism has not been established.

Pseudotime Ordering Single-Cell Transcriptomic ofβCells Pancreatic Islets in Health and Type 2 Diabetes

βcells are defined by the ability to produce and secret insulin.Recent studies have evaluated that human pancreaticβcells are heterogeneous and demonstrated the transcript alterations ofβcell subpopulation in diabetes.Single-cell RNA sequence(scRNA-seq)analysis helps us to refine the cell types signatures and understand the role of theβcells during metabolic challenges and diseases.Here,we construct the pseudotime trajectory ofβcells from publicly available scRNA-seq data in health and type 2 diabetes(T2D)based on highly dispersed and highly expressed genes using Monocle2.We identified three major states including 1)Normal branch,2)Obesity-like branch and 3)T2D-like branch based on biomarker genes and genes that give rise to bifurcation in the trajectory.βcell function-maintain-related genes,insulin expression-related genes,and T2D-related genes enriched in three branches,respectively.Continuous pseudotime spectrum might suggest thatβcells transition among different states.The application of pseudotime analysis is conducted to clarify the different cell states,providing novel insights into the pathology ofβcells in T2D.

WTAP regulates postnatal development of brown adipose tissue by stabilizing METTL3 in mice

Brown adipocyte maturation during postnatal development is essential for brown adipose tissue(BAT)to protect animals against cold.Impaired maturation of brown adipocytes leads to cold intolerance.However,the molecular mechanisms that determine the maturation of brown adipocytes during postnatal development are not fully understood.Here,we identify Wilms’tumor 1-associating protein(WTAP)as an essential regulator in the postnatal development and maturation of BAT.BAT-specific knockout of Wtap(Wtap-BKO)severely impairs maturation of BAT in vivo by decreasing the expression of BAT-selective genes,leading to the whitening of interscapular BAT(iBAT).Single nucleus RNA-sequencing analysis shows the dynamic changes of cell heterogeneity in iBAT of Wtap-BKO mice.Adult mice with WTAP deficiency in BAT display hypothermic and succumb to acute cold challenge.Mechanistically,WTAP deficiency decreases m6A mRNA modification by reducing the protein stability of METTL3.BAT-specific overexpression of Mettl3 partially rescues the phenotypes observed in Wtap-BKO mice.These data demonstrate that WTAP/METTL3 plays an essential role in iBAT postnatal development and thermogenesis.

Intergenerational hyperglycemia through epigenetic alterations of gametes

In a recent study published in Nature,Chen et al.reported a mechanism through which hyperglycemia is transmitted from female mice to their offspring through their eggs and DNA methylation of the paternal-derived pancreatic Gck promoter is increased due to a decrease of maternal effector TET3 dioxygenase.

右位心的患病阈值和多因素遗传模式

右位心指正常生长于左侧的心脏位置或方向发生异常,常伴发复杂的先天性心脏病(先心),发病率约为十万分之八大规模小鼠表型的正向遗传学筛查表明,纤毛基因在先心的发病机制中起着关键作用。然而,右位心这类复杂先天性畸形的遗传模式,其中的遗传病因是否受纤毛基因驱动,以及适用于复杂性状的“全基因”模型能否解释尚不清楚。基于194名右位心患者及对照样本全基因组外显子测序的遗传学分析发现,“单例功能丧失性变异”(Singletonlossof functionvariant,SLoFV)的总数目与右位心显著相关(P=6.4x10-49).当个体携带的SLoFV个数大于8时,携带者发生右位心的风险呈指数增加。进一步通过斑马鱼模型,发现敲降心脏特异性高表达的核心基因,导致心脏结构的致畸率显著高于其他类型的相关基因.结果表明右位心存在基于SLoFV的全基因组遗传风险阈值,并证实了不同权重基因对心脏致畸的不同效应,丰富了全基因组模型下对核心基因遗传效应的理解,为理解复杂疾病右位心的遗传发病机制提供新的理论基础。