Src inhibition modulates AMBRA1-mediated mitophagy to counteract endothelial-to-mesenchymal transition in renal allograft fibrosis.

Chronic allograft dysfunction (CAD) poses a significant challenge in kidney transplantation, with renal vascular endothelial-to-mesenchymal transition (EndMT) playing a vital role. While renal vascular EndMT has been verified as an important contributing factor to renal allograft interstitial fibrosis/tubular atrophy in CAD patients, its underlying mechanisms remain obscure. Currently, Src activation is closely linked to organ fibrosis development. Single-cell transcriptomic analysis in clinical patients revealed that Src is a potential pivotal mediator in CAD progression. Our findings revealed a significant upregulation of Src which closely associated with EndMT in CAD patients, allogeneic kidney transplanted rats and endothelial cells lines. In vivo, Src inhibition remarkably alleviate EndMT and renal allograft interstitial fibrosis in allogeneic kidney transplanted rats. It also had a similar antifibrotic effect in two endothelial cell lines. Mechanistically, the knockout of Src resulted in an augmented AMBRA1-mediated mitophagy in endothelial cells. We demonstrate that Src knockdown upregulates AMBRA1 level and activates mitophagy by stabilizing Parkin's ubiquitination levels and mitochondrial translocation. Subsequent experiments demonstrated that the knockdown of the Parkin gene inhibited mitophagy in endothelial cells, leading to increased production of Interleukin-6, thereby inducing EndMT. Consequently, our study underscores Src as a critical mediator of renal vascular EndMT and allograft interstitial fibrosis, exerting its impact through the regulation of AMBRA1/Parkin-mediated mitophagy.

Rictor/mTORC2 signalling contributes to renal vascular endothelial-to-mesenchymal transition and renal allograft interstitial fibrosis by regulating BNIP3-mediated mitophagy.

BACKGROUND: Renal allograft interstitial fibrosis/tubular atrophy (IF/TA) constitutes the principal histopathological characteristic of chronic allograft dysfunction (CAD) in kidney-transplanted patients. While renal vascular endothelial-mesenchymal transition (EndMT) has been verified as an important contributing factor to IF/TA in CAD patients, its underlying mechanisms remain obscure. Through single-cell transcriptomic analysis, we identified Rictor as a potential pivotal mediator for EndMT. This investigation sought to elucidate the role of Rictor/mTORC2 signalling in the pathogenesis of renal allograft interstitial fibrosis and the associated mechanisms. METHODS: The influence of the Rictor/mTOR2 pathway on renal vascular EndMT and renal allograft fibrosis was investigated by cell experiments and Rictor depletion in renal allogeneic transplantation mice models. Subsequently, a series of assays were conducted to explore the underlying mechanisms of the enhanced mitophagy and the ameliorated EndMT resulting from Rictor knockout. RESULTS: Our findings revealed a significant activation of the Rictor/mTORC2 signalling in CAD patients and allogeneic kidney transplanted mice. The suppression of Rictor/mTORC2 signalling alleviated TNFα-induced EndMT in HUVECs. Moreover, Rictor knockout in endothelial cells remarkably ameliorated renal vascular EndMT and allograft interstitial fibrosis in allogeneic kidney transplanted mice. Mechanistically, Rictor knockout resulted in an augmented BNIP3-mediated mitophagy in endothelial cells. Furthermore, Rictor/mTORC2 facilitated the MARCH5-mediated degradation of BNIP3 at the K130 site through K48-linked ubiquitination, thereby regulating mitophagy activity. Subsequent experiments also demonstrated that BNIP3 knockdown nearly reversed the enhanced mitophagy and mitigated EndMT and allograft interstitial fibrosis induced by Rictor knockout. CONCLUSIONS: Consequently, our study underscores Rictor/mTORC2 signalling as a critical mediator of renal vascular EndMT and allograft interstitial fibrosis progression, exerting its impact through regulating BNIP3-mediated mitophagy. This insight unveils a potential therapeutic target for mitigating renal allograft interstitial fibrosis.

Association of UGT1A Gene Polymorphisms with BKV Infection in Renal Transplantation Recipients.

BACKGROUND: BK virus (BKV) infection is an opportunistic infectious complication and constitutes a risk factor for premature graft failure in kidney transplantation. Our research aimed to identify associations and assess the impact of single-nucleotide polymorphisms (SNPs) on metabolism-related genes in patients who have undergone kidney transplantation with BKV infection.

Material/Methods: The DNA samples of 200 eligible kidney transplant recipients from our center, meeting the inclusion criteria, have been collected and extracted. Next-generation sequencing was used to genotype SNPs on metabolism-associated genes (CYP3A4/5/7, UGT1A4/7/8/9, UGT2B7). A general linear model (GLM) was used to identify and eliminate confounding factors that may influence the outcome events. Multiple inheritance models and haplotype analyses were utilized to identify variation loci associated with infection caused by BKV and ascertain haplotypes, respectively.

Results: A total of 141 SNPs located on metabolism-related genes were identified. After Hardy-Weinberg equilibrium (HWE) and minor allele frequency (MAF) analysis, 21 tagger SNPs were selected for further association analysis. Based on GLM results, no confounding factor was significant in predicting the incidence of BK polyomavirus-associated infection. Then, multiple inheritance model analyses revealed that the risk of BKV infection was significantly associated with rs3732218 and rs4556969. Finally, we detect significant associations between haplotype T-A-C of block 2 (rs4556969, rs3732218, rs12468274) and infection caused by BKV (P = 0.0004).

Conclusions: We found that genetic variants in the UGT1A gene confer BKV infection susceptibility after kidney transplantation.

Enhanced humification via lignocellulosic pretreatment in remediation of agricultural solid waste.

Stover and manure are the main solid waste in agricultural industry. The generation of stover and manure could lead to serious environmental pollution if not handled properly. Composting is the potential greener solution to remediate and reduce agricultural solid waste, through which stover and manure could be remediated and converted into organic fertilizer, but the long composting period and low efficiency of humic substance production are the key constraints in such remediation approach. In this study, we explore the effect of lignocellulose selective removal on composting by performing chemical pretreatment on agricultural waste followed by utilization of biochar to assist in the remediation by co-composting treatment and reveal the impacts of different lignocellulose component on organic fertilizer production. Aiming to discover the key factors that influence humification during composting process and improve the composting quality as well as comprehensive utilization of agricultural solid waste. The results demonstrated that the removal of selective lignin or hemicellulose led to the shift of abundances lignocellulose-degrading bacteria, which in turn accelerated the degradation of lignocellulose by almost 51.2%. The process also facilitated the remediation of organic waste via humification and increased the humic acid level and HA/FA ratio in just 22 days. The richness of media relies on their lignocellulose content, which is negatively correlated with total nitrogen content, humic acid (HA) content, germination index (GI), and pH, but positively correlated with fulvic acid (FA) and total organic carbon (TOC). The work provides a potential cost effective and efficient framework for agricultural solid waste remediation and reduction.

Left ventricular remodeling and its association with mineral and bone disorder in kidney transplant recipients.

BACKGROUND: The assessment of left ventricular (LV) remodeling and its association with mineral and bone disorder (MBD) in kidney transplant recipients (KTRs) have not been systematically studied. We aimed to evaluate LV remodeling changes one year after kidney transplantation (KT) and identify their influencing factors. METHODS: Ninety-five KTRs (68 males; ages 40.2 ± 10.8 years) were followed before and one year after KT. Traditional risk factors and bone metabolism indicators were assessed. Left ventricular mass index (LVMI), left ventricular ejection fraction (LVEF) and left ventricular diastolic dysfunction (LVDD) were measured using two-dimensional transthoracic echocardiography. The relationship between MBD and LV remodeling and the factors influencing LV remodeling were analyzed. RESULTS: One year after KT, MBD was partially improved, mainly characterized by hypercalcemia, hypophosphatemia, hyperparathyroidism, 25-(OH) vitamin D deficiency, elevated bone turnover markers, and bone loss. LVMI, the prevalence of left ventricular hypertrophy (LVH), and the prevalence of LVDD decreased, while LVEF increased. LVH was positively associated with postoperative intact parathyroid hormone (iPTH) and iPTH nonnormalization. △LVMI was positively associated with preoperative type-I collagen N-terminal peptide and postoperative iPTH. LVEF was negatively associated with postoperative phosphorous. △LVEF was negatively associated with postoperative iPTH. LVDD was positively associated with postoperative lumbar spine osteoporosis. Preoperative LVMI was negatively associated with △LVMI and positively associated with △LVEF. Advanced age, increased BMI, diabetes, longer dialysis time, lower albumin level, and higher total cholesterol and low-density lipoprotein levels were associated with LV remodeling. CONCLUSIONS: LV remodeling partially improved after KT, showing a close relationship with MBD.

A retrospective study of mineral and bone disorder in kidney transplant recipients: Single-center experience.

BACKGROUND: The status of mineral and bone disorder (MBD) after kidney transplantation is not fully understood, and the assessment of abnormal mineral and bone metabolism in kidney transplant recipients (KTRs) has not been standardized. MATERIALS AND METHODS: We performed a retrospective analysis of 292 KTRs in our center. The levels of biochemical markers of bone metabolism and bone mineral density (BMD) were assessed. We evaluated the influencing factors of BMD using linear regression analysis. And correlation test was used for the correlation analysis between bone metabolism indicators and other indicators. RESULTS: Postoperative MBD mainly manifested as hypercalcemia (8.9%), hypophosphatemia (27.1%), low levels of 25-hydroxyvitamin D(25(OH)vitD) (67.0%), hyperparathyroidism (50.6%), and high levels of bone turnover markers (BTMs). The prevalence of osteopenia/osteoporosis in the femoral neck (FN) and lumbar spine (LS) was 20.1%/2.8% and 26.1%/3.6%, respectively. Multivariate analysis indicated that FN BMD was positively associated with body mass index (BMI) and negatively associated with acute rejection history (p < 0.05); while LS BMD was positively associated with BMI, and negatively associated with intact parathyroid hormone (iPTH) (p < 0.05). Biochemical markers of bone metabolism were affected by age, sex, preoperative dialysis mode and time, postoperative time, transplanted kidney function, and iPTH levels. LS BMD was negatively correlated with iPTH and BTMs (p < 0.05). CONCLUSION: MBD persisted after kidney transplantation. Decreased bone mass was associated with persistent hyperparathyroidism, acute rejection history, low BMI, advanced age, and menopause. Dynamic monitoring of bone metabolism index and BMD helps to assess MBD after kidney transplantation.

Causal effects of human serum metabolites on occurrence and progress indicators of chronic kidney disease: a two-sample Mendelian randomization study.

Background: Chronic kidney disease (CKD) is often accompanied by alterations in the metabolic profile of the body, yet the causative role of these metabolic changes in the onset of CKD remains a subject of ongoing debate. This study investigates the causative links between metabolites and CKD by leveraging the results of genomewide association study (GWAS) from 486 blood metabolites, employing bulk two-sample Mendelian randomization (MR) analyses. Building on the metabolites that exhibit a causal relationship with CKD, we delve deeper using enrichment analysis to identify the metabolic pathways that may contribute to the development and progression of CKD. Methods: In conducting the Mendelian randomization analysis, we treated the GWAS data for 486 metabolic traits as exposure variables while using GWAS data for estimated glomerular filtration rate based on serum creatinine (eGFRcrea), microalbuminuria, and the urinary albumin-to-creatinine ratio (UACR) sourced from the CKDGen consortium as the outcome variables. Inverse-variance weighting (IVW) analysis was used to identify metabolites with a causal relationship to outcome. Using Bonferroni correction, metabolites with more robust causal relationships are screened. Additionally, the IVW-positive results were supplemented with the weighted median, MR-Egger, weighted mode, and simple mode. Furthermore, we performed sensitivity analyses using the Cochran Q test, MR-Egger intercept test, MR-PRESSO, and leave-one-out (LOO) test. Pathway enrichment analysis was conducted using two databases, KEGG and SMPDB, for eligible metabolites. Results: During the batch Mendelian randomization (MR) analyses, upon completion of the inverse-variance weighted (IVW) approach, sensitivity analysis, and directional consistency checks, 78 metabolites were found to meet the criteria. The following four metabolites satisfy Bonferroni correction: mannose, N-acetylornithine, glycine, and bilirubin (Z, Z), and mannose is causally related to all outcomes of CKD. By pathway enrichment analysis, we identified eight metabolic pathways that contribute to CKD occurrence and progression. Conclusion: Based on the present analysis, mannose met Bonferroni correction and had causal associations with CKD, eGFRcrea, microalbuminuria, and UACR. As a potential target for CKD diagnosis and treatment, mannose is believed to play an important role in the occurrence and development of CKD.