Molecular characterization of m6A RNA methylation regulators with features of immune dysregulation in IgA nephropathy.

The role of RNA N6-methyladenosine (m6A) modification in immunity is being elucidated. This study aimed to explore the potential association between m6A regulators and the immune microenvironment in IgA nephropathy (IgAN). The expression profiles of 24 m6A regulators in 107 IgAN patients were obtained from the Gene Expression Omnibus (GEO) database. The least absolute shrinkage and selection operator (LASSO) regression and logistic regression analysis were utilized to construct a model for distinguishing IgAN from control samples. Based on the expression levels of m6A regulators, unsupervised clustering was used to identify m6A-induced molecular clusters in IgAN. Gene set enrichment analysis (GSEA) and immunocyte infiltration among different clusters were examined. The gene modules with the highest correlation for each of the three clusters were identified by weighted gene co-expression network analysis (WGCNA). A model containing 10 m6A regulators was developed using LASSO and logistic regression analyses. Three molecular clusters were determined using consensus clustering of 24 m6A regulators. A decrease in the expression level of YTHDF2 in IgAN samples was significantly negatively correlated with an increase in resting natural killer (NK) cell infiltration and was positively correlated with the abundance of M2 macrophage infiltration. The risk scores calculated by the nomogram were significantly higher for cluster-3, and the expression levels of m6A regulators in this cluster were generally low. Immunocyte infiltration and pathway enrichment results for cluster-3 differed significantly from those for the other two clusters. Finally, the expression of YTHDF2 was significantly decreased in IgAN based on immunohistochemical staining. This study demonstrated that m6A methylation regulators play a significant role in the regulation of the immune microenvironment in IgAN. Based on m6A regulator expression patterns, IgAN can be classified into multiple subtypes, which might provide additional insights into novel therapeutic methods for IgAN.

Neutrophil diversity and plasticity: Implications for organ transplantation.

Neutrophils, as the first defenders against external microbes and stimuli, are highly active and finely regulated innate immune cells. Emerging evidence has challenged the conventional dogma that neutrophils are a homogeneous population with a short lifespan that promotes tissue damage. Recent findings on neutrophil diversity and plasticity in homeostatic and disease states have centered on neutrophils in the circulation. In contrast, a comprehensive understanding of tissue-specialized neutrophils in health and disease is still lacking. This article will first discuss how multiomics advances have contributed to our understanding of neutrophil heterogeneity and diversification in resting and pathological settings. This discussion will be followed by a focus on the heterogeneity and role of neutrophils in solid organ transplantation and how neutrophils may contribute to transplant-related complications. The goal of this article is to provide an overview of the research on the involvement of neutrophils in transplantation, with the aim that this may draw attention to an underappreciated area of neutrophil research.

Gene signature and prediction model of the mitophagy-associated immune microenvironment in renal ischemia-reperfusion injury.

Background: Renal ischemia-reperfusion injury (IRI) is an inevitable occurrence during kidney transplantation. Mitophagy, ferroptosis, and the associated immune microenvironment (IME) have been shown to play important roles in renal IRI. However, the role of mitophagy-associated IME genes in IRI remains unclear. In this study, we aimed to construct a prediction model of IRI prognosis based on mitophagy-associated IME genes. Method: The specific biological characteristics of the mitophagy-associated IME gene signature were comprehensively analyzed using public databases such as GEO, Pathway Unification, and FerrDb. Correlations between the expression of prognostic genes and immune-related genes and IRI prognosis were determined by Cox regression, LASSO analysis, and Pearson's correlation. Molecular validation was performed using human kidney 2 (HK2) cells and culture supernatant as well as the serum and kidney tissues of mice after renal IRI. Gene expression was measured by PCR, and inflammatory cell infiltration was examined by ELISA and mass cytometry. Renal tissue damage was characterized using renal tissue homogenate and tissue sections. Results: The expression of the mitophagy-associated IME gene signature was significantly correlated with IRI prognosis. Excessive mitophagy and extensive immune infiltration were the primary factors affecting IRI. In particular, FUNDC1, SQSTM1, UBB, UBC, KLF2, CDKN1A, and GDF15 were the key influencing factors. In addition, B cells, neutrophils, T cells, and M1 macrophages were the key immune cells present in the IME after IRI. A prediction model for IRI prognosis was constructed based on the key factors associated with the mitophagy IME. Validation experiments in cells and mice indicated that the prediction model was reliable and applicable. Conclusion: We clarified the relationship between the mitophagy-related IME and IRI. The IRI prognostic prediction model based on the mitophagy-associated IME gene signature provides novel insights on the prognosis and treatment of renal IRI.

Hypoxia-Inducible Factor 2α Attenuates Renal Ischemia-Reperfusion Injury by Suppressing CD36-Mediated Lipid Accumulation in Dendritic Cells in a Mouse Model.

BACKGROUND: Hypoxia and hypoxia-inducible factors (HIFs) play essential and multiple roles in renal ischemia-reperfusion injury (IRI). Dendritic cells (DCs) comprise a major subpopulation of the immunocytes in the kidney and are key initiators and effectors of the innate immune responses after IRI. The role of HIF-2α in DCs remains unclear in the context of renal IRI. METHODS: To investigate the importance of HIF-2α in DCs upon renal IRI, we examined the effects of DC-specific HIF-2α ablation in a murine model. Bone marrow-derived DCs (BMDCs) from DC-specific HIF-2α-ablated mice and wild-type mice were used for functional studies and transcriptional profiling. RESULTS: DC-specific ablation of HIF-2α led to hyperactivation of natural killer T (NKT) cells, ultimately exacerbating murine renal IRI. HIF-2α deficiency in DCs triggered IFN-γ and IL-4 production in NKT cells, along with upregulation of type I IFN and chemokine responses that were critical for NKT cell activation. Mechanistically, loss of HIF-2α in DCs promoted their expression of CD36, a scavenger receptor for lipid uptake, increasing cellular lipid accumulation. Furthermore, HIF-2α bound directly to a reverse hypoxia-responsive element (rHRE) in the CD36 promoter. Importantly, CD36 blockade by sulfo-N-succinimidyl oleate (SSO) reduced NKT cell activation and abolished the exacerbation of renal IRI elicited by HIF-2α knockout. CONCLUSIONS: Our study reveals a previously unrecognized role of the HIF-2α/CD36 regulatory axis in rewiring DC lipid metabolism under IRI-associated hypoxia. These findings suggest a potential therapeutic target to resolve long-standing obstacles in treatment of this severe complication.

Prophylactic effect of low-dose trimethoprim-sulfamethoxazole for Pneumocystis jirovecii pneumonia in adult recipients of kidney transplantation: a real-world data study.

OBJECTIVES: To evaluate the efficacy and safety of low-dose trimethoprim (TMP)-sulfamethoxazole (SMX) (TMP-SMX) as the primary prophylaxis for Pneumocystis jirovecii pneumonia (PJP) in adult recipients of kidney transplantation. METHODS: Three kinds of prescriptions in kidney recipients were documented, including 20 mg TMP/100 mg SMX oral daily, 20 mg TMP/100 mg SMX oral every other day, and nonprophylaxis. The primary outcome was the incidence of PJP in the first 180 days of follow-up after kidney transplantation. The secondary outcomes were changes in renal and liver function. RESULTS: Among the 1469 recipients, 1066 (72.56%) received 20 mg TMP/100 mg SMX daily, 127 (8.65%) received 20 mg TMP/100 mg SMX every other day, and 276 (18.79%) did not have prophylaxis prescription. The 276 recipients in the nonprophylaxis group had 124.92 person-years of follow-up, during which PJP occurred in 29 patients, for an incidence rate of 23.21 (95% confidence interval 15.76-32.72) per 100 person-years. The TMP-SMX daily group and the TMP-SMX every other day group had 524.89 and 62.07 person-years of follow-up, respectively, with no occurrence of PJP. There was no significant difference among the three groups in changes in renal and liver function (P >0.05, respectively). A total of 111 recipients in each group were enrolled in the propensity score matching analysis. It was revealed that the 111 nonprophylaxis recipients had 51.27 person-years of follow-up and 10 PJP cases. Prophylaxis was considered effective because there was a significant difference between the three groups (P <0.001). CONCLUSION: Low-dose TMP-SMX prophylaxis significantly reduces the incidence of PJP within 6 months after kidney transplantation and has a favorable safety profile.

Mesenchymal Stem Cells Alleviate Renal Fibrosis and Inhibit Autophagy via Exosome Transfer of miRNA-122a.

Exosomes derived from mesenchymal stem cell (MSC) alleviate kidney damage through autophagy. This study determined whether MSCs relieve renal fibrosis and inhibit autophagy by exosome transfer of miRNA-122a. The gene expression involved in the mTOR signaling pathway and autophagy was assessed in TGF-ß1-treated human renal tubular epithelial cells (HK-2) and unilateral ureteral obstruction (UUO) mice before and after MSC-derived exosomes and miRNA-122a mimic treatment. Small RNA (sRNA) next-generation sequencing was also performed on TGF-ß1-treated HK-2 cells. MSC-derived exosomes relieve fibrosis caused by TGFß in HK-2 via regulation of the mTOR signaling pathway and downstream autophagy. Furthermore, we found that MSC-derived exosomes mediate miRNA-122a to relieve renal fibrosis in HK-2 cells in response to TGF-ß1 through the regulation of mTOR signaling and autophagy. In the UUO mouse model, miRNA-122a mimic-transfected MSC treatment and its combination with 3-MA both recapitulated the same results as the in vitro experiments, along with reduced expansion of renal tubule, interstitial expansion, and preservation of kidney architecture. The antifibrotic activity of MSC-derived exosomes after renal fibrosis occurs partially by autophagy suppression via excreted exosomes containing mainly miRNA-122a. These findings indicate that the export of miRNA-122a via MSC-derived exosomes represents a novel strategy to alleviate renal fibrosis.

Targeting P2RX1 alleviates renal ischemia/reperfusion injury by preserving mitochondrial dynamics.

Renal ischemia/reperfusion injury (IRI) is the major cause of acute kidney injury. However, mechanisms underlying the sudden loss in kidney function and tissue injury remain to be fully elucidated. Here, we performed RNA sequencing to systematically compare the transcriptome differences between IR injured kidneys and sham kidneys. We observed that mitochondrial dynamics was destructed in renal IRI. Expression of mitochondrial fusion-associated genes was reduced, whereas expression of mitochondrial fission-related genes was increased in renal IRI, and these findings were further confirmed by mitochondrial morphological observations. By screening 19 purinergic receptors, we noticed that P2RX1 expression was markedly upregulated in renal IRI. RNA sequencing and mitochondrial morphological observations revealed that mitochondrial dynamics was preserved in P2RX1 genetic knockout (P2rx1-/-) mice. Neutrophil extracellular traps (NETs) were reported to be essential for tissue injury in renal IRI, but the detailed mechanism remained unclear. In the present study, we found that P2RX1 favored the formation of neutrophil extracellular traps (NETs) in IRI, and NETs was essential for the impairment of mitochondrial dynamics. Mechanistically, P2RX1-involved metabolic interaction between platelets and neutrophils supported NETs formation. Activation of P2RX1 promoted platelets ATP release, which subsequently contributed to neutrophil glycolytic metabolism and NETs generation.

A redox probe screens MTHFD1 as a determinant of gemcitabine chemoresistance in cholangiocarcinoma.

Cholangiocarcinoma (CCA) is a type of solid tumor derived from the bile duct epithelium that features universal gemcitabine resistance. Here, we utilized a gene-encoded ROS biosensor probe (HyPer3 probe) to sort subpopulations with different redox statuses from CCA cells. The isolated HyPer-low subpopulation CCA cells, which exhibited relatively lower cellular ROS levels, exhibited higher chemoresistance to gemcitabine than HyPer-high subpopulation CCA cells in vitro and in vivo. Mechanistically, increased expression of MTHFD1 was found in HyPer-low cells. Knocking down MTHFD1 in HyPer-low cells enhanced cellular ROS and restored sensitivity to gemcitabine. Furthermore, the MTHFD1 inhibitor antifolate compound methotrexate (MTX) increased cellular ROS, and combining gemcitabine with MTX effectively suppressed cholangiocarcinoma cell growth. In summary, the MTHFD1 level mediated the heterogeneous cellular redox status in CCA, which resulted in chemoresistance to gemcitabine. Our data suggest a novel strategy for CCA chemotherapy.

Duodenal perforations secondary to a migrated biliary plastic stent successfully treated by endoscope: case-report and review of the literature.

BACKGROUND: Endoscopic retrograde biliary drainage (ERBD) is the most frequently performed procedure for treating benign or malignant biliary obstruction. Although duodenal perforations secondary to the biliary plastic stent are quite rare, they can be life-threatening. The treatment strategies for such perforations are diverse and continue to be debated. CASE PRESENTATION: We report three cases of duodenal perforation due to the migration of biliary plastic stents that were successfully managed using an endoscope. The three patients were admitted on complaints of abdominal pain after they underwent ERBD. Abdominal computerized tomography (CT) revealed migration of the biliary plastic stents and perforation of the duodenum. Endoscopy was immediately performed, and perforation was confirmed. All migrated stents were successfully extracted endoscopically by using snares. In two of the three cases, the duodenal defects were successfully closed with haemostatic clips after stent retrieval, and subsequently, endoscopic nasobiliary drainage tubes were inserted. After the endoscopy and medical treatment, all three patients recovered completely. CONCLUSIONS: Duodenal perforations due to the migration of biliary stents are rare, and the treatment strategies remain controversial. Our cases and cases in the literature demonstrate that abdominal CT is the preferred method of examination for such perforations, and endoscopic management is appropriate as a first-line treatment approach.

Calcipotriol Inhibits NLRP3 Signal Through YAP1 Activation to Alleviate Cholestatic Liver Injury and Fibrosis.

Cholestasis is common in multiple clinical circumstances. The NOD-like receptor protein 3 (NLRP3) inflammasome pathway has been demonstrated to play an important role in liver injury and fibrosis induced by cholestasis. We previously proved that MCC950, a selective NLRP3 inhibitor, alleviates liver fibrosis and injury in experimental liver cholestasis induced by bile-duct ligation (BDL) in mice. Herein, we investigate the role of calcipotriol, a potent vitamin D receptor agonist, in experimental liver cholestasis, test its therapeutic efficacy, and explore its potential protective mechanism. C57BL/6 mice were made to undergo BDL or fed the 0.1% 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet to establish two classic cholestatic models. Calcipotriol was administered intraperitoneally to these mice daily. Serum makers of liver damage and integrity, liver histological changes, levels of liver pro-fibrotic markers, bile acid synthetases and transporters were measured in vivo. The underlying mechanism by which calcipotriol alleviates cholestatic liver injury and fibrosis was further investigated. The results of the current study demonstrated that calcipotriol supplement significantly alleviate cholestatic liver injury and fibrosis. Moreover, calcipotriol supplement markedly inhibited NLRP3 inflammasome pathway activation to alleviate liver injury and fibrosis in vivo and inhibit hepatic stellate cell (HSC) activation in vitro. In addition, VDR agonist calcipotriol exert inhibitory effect on NLRP3 inflammasome activation through activating yes-associated protein 1 (YAP1). In conclusion, our findings proved that calcipotriol suppressed the NLRP3 signal by activating YAP1 to alleviate liver injury and retard fibrogenesis in cholestasis.

Feasibility and safety of single-incision laparoscopic cholecystectomy versus conventional laparoscopic cholecystectomy in an ambulatory setting.

BACKGROUND: Single-incision laparoscopic surgery has emerged as an alternative to conventional laparoscopic cholecystectomy (LC) in the clinical setting. Limited information is available on the possibility of performing single-incision laparoscopic surgery as an ambulatory procedure. This study aimed to determine the feasibility and safety of single-incision laparoscopic cholecystectomy (SILC) versus conventional LC in an ambulatory setting. METHODS: Ninety-one patients were randomized to SILC (n = 49) or LC (n = 42). The success rate, operative duration, blood loss, hospital stay, gallbladder perforation, drainage, delayed discharge, readmission, total cost, complications, pain score, vomiting, and cosmetic satisfaction of the two groups were then compared. RESULTS: There were significant differences in the operative time (46.89 ±â€¯10.03 min in SILC vs. 37.24 ±â€¯10.23 min in LC; P < 0.001). As compared with LC, SILC was associated with lower total costs (8012.28 ±â€¯752.67 RMB vs. 10258.91 ± 1087.63 RMB; P < 0.001) and better cosmetic satisfaction (4.94 ± 0.24 vs. 4.74 ± 0.54; P = 0.031). There were no significant differences between-group in terms of general data, success rate, blood loss, hospital stay, gallbladder perforation, drainage, delayed discharge, readmission, complications, pain score, and vomiting (P > 0.05). CONCLUSIONS: Ambulatory SILC is safe and feasible for selected patients. The advantages of SILC as compared with LC are improved cosmetic satisfaction and lower total costs.

The selective NLRP3 inflammasome inhibitor MCC950 alleviates cholestatic liver injury and fibrosis in mice.

Cholestasis occurs in many clinical circumstances and leads to severe liver disorders. MCC950, a small-molecule NLRP3 inhibitor, was previously shown to have anti-inflammatory effects. However, these effects have not yet been examined in cholestatic liver injury. This study aimed to investigate the role of NLRP3 inflammasome and test the therapeutic efficacy and molecular mechanisms of MCC950 in cholestatic liver injury through the common bile duct ligation (BDL) model in mice. The influence of MCC950 on histological changes, levels of liver damage, neutrophil infiltration, liver cell death, inflammatory cytokine levels, and NLRP3 inflammasome expression were examined. The results of the current study confirmed that NLRP3 components were up-regulated during bile duct obstruction. MCC950 treatment significantly alleviated BDL-induced liver injury by reducing production of the pro-inflammatory cytokines IL-1ß and IL-18 and inhibiting neutrophil infiltration and hepatic cell death. Moreover, MCC950 significantly inhibited NLRP3 activation during cholestatic liver injury. In addition, transcriptome analysis indicated that Toll-like receptor signaling may be involved in the protective effects of MCC950 in cholestatic liver injury. In conclusion, experimental findings demonstrate that MCC950 exerted protective effects in cholestatic liver injury and liver fibrosis by blocking NLRP3 inflammasome activation and the mechanism was partially attributed to inhibition of Toll-like receptor signaling. The present study indicates MCC950 could potentially be an effective therapeutic strategy for the treatment of cholestatic liver injury.

9-cis-retinoic acid elevates MRP3 expression by inhibiting sumoylation of RXRα to alleviate cholestatic liver injury.

AIMS: Vitamin A and its metabolites has been found to be protective against cholestatic liver injury, but the exact underlying mechanisms involved in cholestatic liver injury remain unclear. The objective of this study was to determine the function and mechanisms of 9-cis-retinoic acid, the metabolite of vitamin A, in cholestatic liver injury. METHODS: The bile duct ligated (BDL) mice were treated with 9-cis-retinoic acid by intravenous injection through the tail for 10 days. The liver function and histology were assessed in the matched group and experimental group. The expression of MRP3 in liver tissue was tested by qRT-PCR, Western blotting, and IHC. Effect of RXRα sumoylation on MRP3 expression was investigated at a cellular level. Influence of 9-cis-retinoic acid on RXRα sumoylation was also tested in cells. RESULTS: Our findings showed that 9-cis-retinoic acid significantly decreases the serum ALT and AST level, alleviates hepatic necrosis of the BDL-mice. We also identified MRP3, an important protective hepatobiliary transporter in cholestasis, was elevated by 9-cis-retinoic acid in vivo and in vitro. 9-cis-retinoic acid weakened the sumoylation of RXRα, which promotes the cytoplasmic location of RXRα and lightens the interaction of RXRα and RARα. Inhibition of RXRα and RARα interaction increased MRP3 expression. CONCLUSIONS: 9-cis-retinoic acid alleviates cholestatic liver injury by elevating MRP3 expression through its mechanism of inhibiting sumoylation of RXRα.

Hem-o-lok Clips Migration: An Easily Neglected Complication after Laparoscopic Biliary Surgery.

Clip migration into the common bile duct (CBD) is a rare but well-established phenomenon of laparoscopic biliary surgery. The mechanism and exact incidence of clip migration are both poorly understood. Clip migration into the common bile duct can cause recurrent cholangitis and serve as a nidus for stone formation. We present a case, a 54-year-old woman, of clip-induced cholangitis resulting from surgical clip migration 12 months after laparoscopic cholecystectomy and laparoscopic common bile duct exploration (LC+LCBDE) with primary closure.