Optophysiology: Illuminating cell physiology with optogenetics.

Optogenetics combines light and genetics to enable precise control of living cells, tissues, and organisms with tailored functions. Optogenetics has the advantages of noninvasiveness, rapid responsiveness, tunable reversibility, and superior spatiotemporal resolution. Following the initial discovery of microbial opsins as light-actuated ion channels, a plethora of naturally occurring or engineered photoreceptors or photosensitive domains that respond to light at varying wavelengths has ushered in the next chapter of optogenetics. Through protein engineering and synthetic biology approaches, genetically encoded photoswitches can be modularly engineered into protein scaffolds or host cells to control a myriad of biological processes, as well as to enable behavioral control and disease intervention in vivo. Here, we summarize these optogenetic tools on the basis of their fundamental photochemical properties to better inform the chemical basis and design principles. We also highlight exemplary applications of opsin-free optogenetics in dissecting cellular physiology (designated "optophysiology") and describe the current progress, as well as future trends, in wireless optogenetics, which enables remote interrogation of physiological processes with minimal invasiveness. This review is anticipated to spark novel thoughts on engineering next-generation optogenetic tools and devices that promise to accelerate both basic and translational studies.

A methanotrophic bacterium to enable methane removal for climate mitigation.

The rapid increase of the potent greenhouse gas methane in the atmosphere creates great urgency to develop and deploy technologies for methane mitigation. One approach to removing methane is to use bacteria for which methane is their carbon and energy source (methanotrophs). Such bacteria naturally convert methane to CO2 and biomass, a value-added product and a cobenefit of methane removal. Typically, methanotrophs grow best at around 5,000 to 10,000 ppm methane, but methane in the atmosphere is 1.9 ppm. Air above emission sites such as landfills, anaerobic digestor effluents, rice paddy effluents, and oil and gas wells contains elevated methane in the 500 ppm range. If such sites are targeted for methane removal, technology harnessing aerobic methanotroph metabolism has the potential to become economically and environmentally viable. The first step in developing such methane removal technology is to identify methanotrophs with enhanced ability to grow and consume methane at 500 ppm and lower. We report here that some existing methanotrophic strains grow well at 500 ppm methane, and one of them, Methylotuvimicrobium buryatense 5GB1C, consumes such low methane at enhanced rates compared to previously published values. Analyses of bioreactor-based performance and RNAseq-based transcriptomics suggest that this ability to utilize low methane is based at least in part on extremely low non-growth-associated maintenance energy and on high methane specific affinity. This bacterium is a candidate to develop technology for methane removal at emission sites. If appropriately scaled, such technology has the potential to slow global warming by 2050.

Optogenetics for transcriptional programming and genetic engineering.

Optogenetics combines genetics and biophotonics to enable noninvasive control of biological processes with high spatiotemporal precision. When engineered into protein machineries that govern the cellular information flow as depicted in the central dogma, multiple genetically encoded non-opsin photosensory modules have been harnessed to modulate gene transcription, DNA or RNA modifications, DNA recombination, and genome engineering by utilizing photons emitting in the wide range of 200-1000 nm. We present herein generally applicable modular strategies for optogenetic engineering and highlight latest advances in the broad applications of opsin-free optogenetics to program transcriptional outputs and precisely manipulate the mammalian genome, epigenome, and epitranscriptome. We also discuss current challenges and future trends in opsin-free optogenetics, which has been rapidly evolving to meet the growing needs in synthetic biology and genetics research.

Assembly of the WHIP-TRIM14-PPP6C Mitochondrial Complex Promotes RIG-I-Mediated Antiviral Signaling.

Mitochondrial antiviral signaling platform protein (MAVS) acts as a central hub for RIG-I receptor proximal signal propagation. However, key components in the assembly of the MAVS mitochondrial platform that promote RIG-I mitochondrial localization and optimal activation are still largely undefined. Employing pooled RNAi and yeast two-hybrid screenings, we report that the mitochondrial adaptor protein tripartite motif (TRIM)14 provides a docking platform for the assembly of the mitochondrial signaling complex required for maximal activation of RIG-I-mediated signaling, consisting of WHIP and protein phosphatase PPP6C. Following viral infection, the ubiquitin-binding domain in WHIP bridges RIG-I with MAVS by binding to polyUb chains of RIG-I at lysine 164. The ATPase domain in WHIP contributes to stabilization of the RIG-I-dsRNA interaction. Moreover, phosphatase PPP6C is responsible for RIG-I dephosphorylation. Together, our findings define the WHIP-TRIM14-PPP6C mitochondrial signalosome required for RIG-I-mediated innate antiviral immunity.

Vitamin D May Play a Vital Role in Alleviating Type 2 Diabetes Mellitus by Modulating the Ferroptosis Signaling Pathway.

Ferroptosis is an iron-dependent death mode mediated by the aggregation of lipid peroxides and lipid-reactive oxygen species. It is characterized by iron-dependent lipid peroxide accumulation accompanied by oxidoreductase deficiency. Pancreatic beta cell dysfunction and insulin resistance are two major causes of type 2 diabetes mellitus (T2DM). Iron accumulation and metabolism may play a role in the development of T2DM. The molecular mechanism of ß cell apoptosis and iron death in T2DM were reviewed. In addition, we discuss recent insights on the relationship between the trace element iron and apoptosis of ß cells in T2DM.

TRIM14 Inhibits cGAS Degradation Mediated by Selective Autophagy Receptor p62 to Promote Innate Immune Responses.

Cyclic GMP-AMP synthase (cGAS) is an essential DNA virus sensor that triggers type I interferon (IFN) signaling by producing cGAMP to initiate antiviral immunity. However, post-translational regulation of cGAS remains largely unknown. We report that K48-linked ubiquitination of cGAS is a recognition signal for p62-depdendent selective autophagic degradation. The induction of TRIM14 by type I IFN accelerates cGAS stabilization by recruiting USP14 to cleave the ubiquitin chains of cGAS at lysine (K) 414. Knockout of TRIM14 impairs herpes simplex virus type 1 (HSV-1)-triggered antiviral responses in a cGAS-dependent manner. Due to impaired type I IFN production, Trim14-/- mice are highly susceptible to lethal HSV-1 infection. Taken together, our findings reveal a positive feedback loop of cGAS signaling generated by TRIM14-USP14 and provide insights into the crosstalk between autophagy and type I IFN signaling in innate immunity.

Optical control of protein delivery and partitioning in the nucleolus.

The nucleolus is a subnuclear membraneless compartment intimately involved in ribosomal RNA synthesis, ribosome biogenesis and stress response. Multiple optogenetic devices have been developed to manipulate nuclear protein import and export, but molecular tools tailored for remote control over selective targeting or partitioning of cargo proteins into subnuclear compartments capable of phase separation are still limited. Here, we report a set of single-component photoinducible nucleolus-targeting tools, designated pNUTs, to enable rapid and reversible nucleoplasm-to-nucleolus shuttling, with the half-lives ranging from milliseconds to minutes. pNUTs allow both global protein infiltration into nucleoli and local delivery of cargoes into the outermost layer of the nucleolus, the granular component. When coupled with the amyotrophic lateral sclerosis (ALS)-associated C9ORF72 proline/arginine-rich dipeptide repeats, pNUTs allow us to photomanipulate poly-proline-arginine nucleolar localization, perturb nucleolar protein nucleophosmin 1 and suppress nascent protein synthesis. pNUTs thus expand the optogenetic toolbox by permitting light-controllable interrogation of nucleolar functions and precise induction of ALS-associated toxicity in cellular models.

Bbhox2 is a key regulator for conidiation and virulence in Beauveria bassiana.

Beauveria bassiana, a well-known filamentous biocontrol fungus, is the main pathogen of numerous field and forest pests. To explore the potential factors involved in the fungal pathogenicity, Bbhox2, an important and conserved functional transcription factor containing homeodomain was carried out by functional analysis. Homologous recombination was used to disrupt the Bbhox2 gene in B.bassiana. The conidia yield of the deletant fungal strain was significantly reduced. The conidial germination was faster, and stress tolerance to Congo red and high osmotic agents were decreased compared with that in the wildtype. Additionally, ΔBbhox2 showed a dramatic reduction in virulence no matter in topical inoculations or in intra-hemolymph injections against Galleria mellonella larvae, which is likely due to the failure of appressorium formation and the defect in producing hyphal body. These results indicate that the Bbhox2 gene markedly contributes to conidiation and pathogenicity in B. bassiana.

Zimberelimab combined with systemic therapy extended tumor control in post-radiotherapy cervical cancer with brain metastases: A case report.

Out of the total cases of cervical cancer, brain metastases (BMs) are relatively rare, with an estimated incidence rate of 0.63% (range: 0.1%-2.2%). Additionally, BMs prognosis remains poor, and the average patient survival time following a BM diagnosis is 3 to 5 months. Few studies have addressed the effect of programmed cell death-1 inhibitors against BMs in cervical cancer, although they are an established option for recurrent/metastatic disease. Hence, we report a case involving a 54-year-old post-surgery patient with cervical cancer with a body mass index of 19.5 kg/m2 and Eastern Collaborative Oncology Group (ECOG) performance status of 3; the disease recurred with BMs 1 year later. Intensity-modulated radiation therapy concurrent with temozolomide and bevacizumab was initiated, following which zimberelimab immunotherapy combined with anlotinib was administered to extend tumor control. The patient had a progression-free survival duration of 10 months, the tumor response was assessed as a partial response based on the evaluation criteria for solid tumors (RECIST1.1), and the ECOG status improved to 1 after therapy. These findings suggest that immunotherapy-based combination therapy following radiotherapy may be a good choice for patients with cervical cancer and BMs.

PREVALENCE OF DEPRESSION AMONG UNIVERSITY STUDENTS IN CHINA: A PROTOCOL FOR A SYSTEMATIC REVIEW AND META-ANALYSIS.

BACKGROUND: Depression is a mental disorder characterized by a persistent and long-lasting depressive mood. OBJECTIVE: The aim of this study was to analyze the prevalence of depression among university students in China and to provide guidance for psychological intervention and improvement of depression among this specific population. METHODS: A systematic search was conducted on PubMed, CNKI, Wang-fang database, and Web of Science to identify relevant articles. The articles were cross-sectional studies focusing on the prevalence of depression among university students in China, with clearly defined criteria for diagnosing depression included. Excel was used independently and in duplicate to perform the screening process that involved title, abstract screening, full-text screening, data extraction and assessment of risk of bias. The standards recommended by the Agency for Healthcare Research and Quality (AHRQ) was used to evaluate the quality of observational studies. RESULTS: STATA 11.0 was used to pool the outcomes and perform meta-analysis, including the prevalence of depression among university students and influential factors such as sex, major, region, and the impact of COVID-19. CONCLUSION: Practical psychological interventions are needed in universities in China. Continuously attention is suggested to be paid to Chinese university students' mental health, especially after public health event such as COVID-19.

Vitamin D may alleviate pre-eclampsia by modulating the ferroptosis signalling pathway: A hypothesis based on recent literature.

Ferroptosis is a novel form of regulated cell death typically characterized by non-apoptotic, iron-dependent, and reactive accumulation of oxygen species. Recent studies have found that ferroptosis plays an important role in the pathophysiology of pre-eclampsia (PE). In order to find potential therapeutic targets for ferroptosis intervention and better prevent the occurrence and progression of PE, the signalling pathways that regulate ferroptosis need to be identified. In this article, we review the role of vitamin D in PE and the role of ferroptosis in PE. Based on recent literature, we propose the scientific hypothesis that vitamin D can alleviate preeclampsia by modulating the ferroptosis signalling pathway. The aim of this review is to understand the regulatory pathways of ferroptosis in PE and to identify potential therapeutic targets.

Narrative review of ferroptosis in obesity.

Obesity is widely recognized as a major global health problem caused by a chronic energy imbalance resulting from a combination of excess caloric intake and insufficient energy expenditure. Excessive energy intake and physical inactivity are traditional risk factors for obesity. Obesity is a risk factor for many diseases, including hypertension, diabetes and tumours. Recent studies have found a strong link between ferroptosis and obesity. Ferroptosis is an iron-dependent regulated cell death caused by iron overload and reactive oxygen species-dependent excessive accumulation of lipid peroxidation. Ferroptosis is involved in many biological processes, such as amino acid metabolism, iron metabolism and lipid metabolism. Some potential strategies to reduce the adverse effects of ferroptosis on obesity are suggested and future research priorities are highlighted.

Cre/lox-Mediated CRISPRi Library Reveals Core Genome of a Type I Methanotroph Methylotuvimicrobium buryatense 5GB1C.

Methanotrophs play key roles in global methane cycling and are promising platforms for methane bioconversion. However, major gaps existing in fundamental knowledge undermines understanding of these methane-consuming microorganisms. To associate genes with a phenotype at the genome-wide level, we developed a Cre/lox-mediated method for constructing a large-scale CRISPRi library in a model methanotroph Methylotuvimicrobium buryatense 5GB1C. The efficiency of this Cre mediated integration method was up to a level of 105 CFU/µg DNA. Targeting 4,100 predicted protein-coding genes, our CRISPRi pooled screening uncovered 788 core genes for the growth of strain 5GB1C using methane. The core genes are highly consistent with the gene knockout results, indicating the reliability of the CRISPRi screen. Insights from the core genes include that annotated isozymes generally exist in metabolic pathways and many core genes are hypothetical genes. This work not only provides functional genomic data for both fundamental research and metabolic engineering of methanotrophs, but also offers a method for CRISPRi library construction. IMPORTANCE Due to their key role in methane cycling and their industrial potential, methanotrophs have drawn increasing attention. Genome-wide experimental approaches for gene-phenotype mapping accelerate our understanding and engineering of a bacterium. However, these approaches are still unavailable in methanotrophs. This work has two significant implications. First, the core genes identified here provide functional genetic basics for complete reconstruction of the metabolic network and afford more clues for knowledge gaps. Second, the Cre-mediated knock-in method developed in this work enables large-scale DNA library construction in methanotrophs; the CRISPRi library can be used to screen the genes associated with special culture conditions.

Circularly permuted LOV2 as a modular photoswitch for optogenetic engineering.

Plant-based photosensors, such as the light-oxygen-voltage sensing domain 2 (LOV2) from oat phototropin 1, can be modularly wired into cell signaling networks to remotely control protein activity and physiological processes. However, the applicability of LOV2 is hampered by the limited choice of available caging surfaces and its preference to accommodate the effector domains downstream of the C-terminal Jα helix. Here, we engineered a set of LOV2 circular permutants (cpLOV2) with additional caging capabilities, thereby expanding the repertoire of genetically encoded photoswitches to accelerate the design of optogenetic devices. We demonstrate the use of cpLOV2-based optogenetic tools to reversibly gate ion channels, antagonize CRISPR-Cas9-mediated genome engineering, control protein subcellular localization, reprogram transcriptional outputs, elicit cell suicide and generate photoactivatable chimeric antigen receptor T cells for inducible tumor cell killing. Our approach is widely applicable for engineering other photoreceptors to meet the growing need of optogenetic tools tailored for biomedical and biotechnological applications.

The crescent-like Golgi ribbon is shaped by the Ajuba/PRMT5/Aurora-A complex-modified HURP.

BACKGROUND: Golgi apparatus (GA) is assembled as a crescent-like ribbon in mammalian cells under immunofluorescence microscope without knowing the shaping mechanisms. It is estimated that roughly 1/5 of the genes encoding kinases or phosphatases in human genome participate in the assembly of Golgi ribbon, reflecting protein modifications play major roles in building Golgi ribbon. METHODS: To explore how Golgi ribbon is shaped as a crescent-like structure under the guidance of protein modifications, we identified a protein complex containing the scaffold proteins Ajuba, two known GA regulators including the protein kinase Aurora-A and the protein arginine methyltransferase PRMT5, and the common substrate of Aurora-A and PRMT5, HURP. Mutual modifications and activation of PRMT5 and Aurora-A in the complex leads to methylation and in turn phosphorylation of HURP, thereby producing HURP p725. The HURP p725 localizes to GA vicinity and its distribution pattern looks like GA morphology. Correlation study of the HURP p725 statuses and GA structure, site-directed mutagenesis and knockdown-rescue experiments were employed to identify the modified HURP as a key regulator assembling GA as a crescent ribbon. RESULTS: The cells containing no or extended distribution of HURP p725 have dispersed GA membranes or longer GA. Knockdown of HURP fragmentized GA and HURP wild type could, while its phosphorylation deficiency mutant 725A could not, restore crescent Golgi ribbon in HURP depleted cells, collectively indicating a crescent GA-constructing activity of HURP p725. HURP p725 is transported, by GA membrane-associated ARF1, Dynein and its cargo adaptor Golgin-160, to cell center where HURP p725 forms crescent fibers, binds and stabilizes Golgi assembly factors (GAFs) including TRIP11, GRASP65 and GM130, thereby dictating the formation of crescent Golgi ribbon at nuclear periphery. CONCLUSIONS: The Ajuba/PRMT5/Aurora-A complex integrates the signals of protein methylation and phosphorylation to HURP, and the HURP p725 organizes GA by stabilizing and recruiting GAFs to its crescent-like structure, therefore shaping GA as a crescent ribbon. Therefore, the HURP p725 fiber serves a template to construct GA according to its shape. Video Abstract.

Higher serum trimethylamine N-oxide (TMAO) levels are associated with increased visceral fat in hemodialysis patients.

BACKGROUND: Trimethylamine N-oxide (TMAO), a gut microbiota-derived metabolite, has emerged as a new potentially important cause of increased atherosclerosis and cardiovascular risk in chronic kidney disease (CKD) patients. However, the possible causes whereby TMAO potentiates atherosclerosis development remain poorly defined. The strong association between gut microbiota and obesity suggested that the TMAO pathway may be linked to the pathogenesis of obesity. MATERIALS AND METHODS: A total of 184 hemodialysis (HD) patients and 38 healthy controls were enrolled in the study from March 2019 to May 2019. We evaluated visceral fat area (VFA) by anthropometric measurement and measured serum TMAO concentrations using liquid chromatography/differential ion mobility spectrometry tandem mass spectrometry. We also examined the relationship between TMAO levels and visceral fat accumulation. RESULTS: TMAO level was markedly higher in HD patients than in control subjects (5.80 (3.96, 9.46) vs. 0.18 (0.11, 0.32) µg/mL, p < 0.01), and its level in diabetic HD patients was significantly higher than in nondiabetic patients (6.93 (4.67, 11.40) vs. 5.25 (3.78, 8.02) µg/mL, p < 0.01). A significant positive correlation was found between serum TMAO level and VFA in these patients (r = 0.282, p = 0.005). Multiple regression analysis showed that Ln(TMAO) was independently associated with Ln(VFA) in HD patients (p = 0.008). CONCLUSION: Our results showed that there was a significant positive correlation between serum TMAO levels and visceral fat in HD patients, which suggested that TMAO may predict cardiovascular risk through increased visceral fat.

Mental Health Among University Students, Using the 12-item General Health Questionnaire.

Context: To date, researchers have found that poor mental health was common during the COVID-19 epidemic. Even if they had been relatively resistant to suicidal ideation during the first three waves of the pandemic, university students may experience a delayed impact on their mental health. Objective: The study intended to measure mental health among university students in Wuhu City, China and to identify an effective approach to universities can use to prevent mental-health issues. Design: The research team performed a cross-sectional study. Setting: The study took place at Anhui polytechnic university, Wuhu, China. Participants: Participants were 2371 students at Anhui polytechnic university in Wuhu city, China. Outcome Measures: The research team used the two-item General Health Questionnaire-12 (GHQ-12) to measure participants' mental health. Results: Among the 2371 participants, 1727 had poor mental health (72.84%), including 843 males (48.81%) and 884 females (51.19%). Poor mental health was significantly associated with an urban residential location (P > .01), the female gender (p>0.01), the second school year (P > .01), and the parents' education level of junior high school or below (both P > .01). Conclusions: The current study suggests that poor mental health among university students is common. Being female, from an urban area, and in the second year of school and having parents with an education of junior high school or below had poorer mental health than those who were male, from the countryside, and in the first year of school and who had parents with a higher level of education.

Self-report Sleep Quality and its Risk Factors Among Community-dwelling Older Adults in China.

Context: Researchers have associated insomnia with many disorders, making insomnia a serious public health issue in China. Sleep quality in older adults isn't well characterized in China. Objective: The study intended to explore the sleep quality and subjective duration of sleep in a community-dwelling older population in China and identify potential risk factors for poor sleep. Design: The research team performed a cross-sectional survey using the convenience sampling method. Setting: The study took place in a community in Wuhu, Anhui, China in 2015. Participants: Participants were 1075 members of the community from Wuhu city. Outcome Measures: The research team collected self-reported information on sleep quality. Results: The overall prevalence of self-reported insomnia among older adults were 40.8%. The prevalence of insomnia in females, 259 (59.00%), was significantly higher than in males, 180 (41.00%), with P = .00. For income status, the prevalence of insomnia was significantly higher for participants with less than 10 000 RMB per year income for a family, 191 participants (43.51%), than for participants with higher family incomes, with P = .00. For marital status, the prevalence of insomnia was significantly higher for the widowed participants, 121 participants (24.56%), with P = .01. Conclusions: Sleep quality for females, low-income families, and widowed people were significantly worse than for people in other categories among older adults in China. Older adults in China need proper interventions for the factors causing poor sleep hygiene.

Elevated serum fatty acid-binding protein 4 level predicts all-cause and cardiovascular mortality in peritoneal dialysis patients: a five-year study.

BACKGROUND: To explore the prospective role of serum fatty acid-binding protein 4 (FABP4) in the outcomes of peritoneal dialysis (PD) patients. METHODS: A prospective observational study was conducted with 159 patients on PD. Demographic and clinical data at baseline were collected from medical records. Biochemical data were recorded based on blood samples measured in a central laboratory. Serum FABP4 concentrations were determined using enzyme-linked immunosorbent assay. Body composition was measured using a Body Composition Monitor. Abdominal lateral plain radiography was used to evaluate vascular calcification. The primary endpoints were all-cause and cardiovascular death. RESULTS: The median of serum FABP4 concentration was 154.6 ng/mL (interquartile range, 132.8-269.7 ng/mL). Increased serum FABP4 was associated with increased vascular calcification proportion, time on dialysis, body mass index, high-sensitivity C-reactive protein (hs-CRP), intact parathyroid hormone (iPTH), triglycerides, body fat mass, and body fat percentage (p < 0.05). Increased serum FABP4 was associated with decreased residual kidney Kt/V urea (p < 0.05). Patients with hs-CRP≥ 3 mg/L had significantly higher serum FABP4 than those with hs-CRP< 3 mg/L (p < 0.05). Patients with vascular calcification had significantly higher serum FABP4 than those without vascular calcification (p < 0.05). During a median follow-up of 58.0 months, 58 all-cause deaths and 26 cardiovascular deaths occurred. High serum FABP4 levels were independently predictive for all-cause [hazard ratio (HR), 1.003; 95% confidence interval (CI), 1.001-1.005; p = 0.016] and cardiovascular death (HR, 1.005; 95% CI, 1.001-1.008; p = 0.006) in PD patients. CONCLUSIONS: Increased serum FABP4 levels can independently predict all-cause and cardiovascular death in patients on PD.

Relationship between gut microbiota and vascular calcification in hemodialysis patients.

INTRODUCTION: Vascular calcification (VC) is an independent risk factor for cardiovascular mortality in end-stage renal disease (ESRD) patients. The pathogenesis of VC is complicated and unclear. Uremic toxins produced by gut microbiota can promote VC. This study aims to identify the differences in gut microbiota between the different VC groups and the main bacteria associated with VC in hemodialysis (HD) patients in an attempt to open up new preventive and therapeutic approaches and define the probable mechanism for VC in HD patients in the future. METHODS: A total of 73 maintenance HD patients were enrolled in this cross-sectional study. According to the abdominal aortic calcification (AAC) scores, the participants were divided into the high AAC score group and the low AAC score group. High-throughput sequencing of the gut microbiota was performed and the results were evaluated by alpha diversity, beta diversity, species correlation, and model predictive analyses. RESULTS: The prevalence of VC was 54.79% (40/73) in the study. The majority of phyla in the two groups were the same, including Firmicutes, Actinobacteriota, Proteobacteria, and Bacteroidota. The microbial diversity in the high AAC score group had a decreasing trend (p = 0.050), and the species abundance was significantly lower (p = 0.044) than that in the low AAC score group. The HD patients with high AAC scores showed an increased abundance of Proteobacteria and decreased abundances of Bacteroidota and Synergistota at the phylum level; increased abundances of Escherichia-Shigella, Ruminococcus_gnavus_group, and Lactobacillus; and decreased abundances of Ruminococcus and Lachnospiraceae_NK4A136_group at the genus level (p<0.05). Escherichia-Shigella and Ruminococcus_gnavus_group were positively correlated with VC, and Ruminococcus, Adlercreutzia, Alistipes, and norank_f__Ruminococcaceae were negatively correlated with VC. Escherichia-Shigella had the greatest influence on VC in HD patients, followed by Ruminococcus and Butyricimonas. CONCLUSIONS: Our results provide clinical evidence that there was a difference in gut microbiota between the different VC groups in HD patients. Escherichia-Shigella, a lipopolysaccharide (LPS)-producing bacterium, was positively correlated with VC and had the greatest influence on VC. Ruminococcus, a short-chain fatty acid (SCFA)-producing bacterium, was negatively correlated with VC and had the second strongest influence on VC in HD patients. The underlying mechanism is worth studying. These findings hint at a new therapeutic target.