Label-free MXene-assisted field effect transistor for the determination of IL-6 in patients with kidney transplantation infection.

A spiral interdigitated MXene-assisted field effect transistor (SiMFETs) was proposed for determination of IL-6 in patients with kidney transplantation infection. Our SiMFETs demonstrated enhanced IL-6 detection range of 10 fg/mL-100 ng/mL due to the combination of optimized transistor's structure and semiconducting nanocomposites. Specifically, on one hand, MXene-based field effect transistor drastically amplified the amperometric signal for determination of IL-6; on the other hand, the multiple spiral structure of interdigitated drain-source architecture improved the transconductance of FET biosensor. The developed SiMFETs biosensor demonstrated satisfactory stability for 2 months, and favorable reproducibility and selectivity against other biochemical interferences. The SiMFETs biosensor exhibited acceptable correlation coefficient (R2=0.955) in quantification of clinical biosamples. The sensor successfully distinguished the infected patients from the health control with enhanced AUC of 0.939 (sensitivity of 91.7%, specificity of 86.7%). Those merits introduced here may pave an alternative strategy for transistor-based biosensor in point-of-care clinic applications.

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.

The minimum weight and age of kidney donors: en bloc kidney transplantation from preterm neonatal donors weighing less than 1.2 kg to adult recipients.

En bloc kidney transplantation (EBKT) to adults from preterm neonates following donation after circulatory death has not been described in the literature. We report 2 successful cases of EBKT from preterm neonatal donation after circulatory death donors weighing <1.2 kg to adult recipients. The first case was a preterm female infant born at 29 weeks' gestational age, weighing 1.07 kg. The recipient was a 34-year-old woman weighing 75 kg. At the 9-month follow-up, the patient demonstrated excellent graft function with a creatinine concentration of 1.48 mg/dL. The second donor was a preterm female infant born at 29 weeks and 5 days' gestation, weighing 1.17 kg. The recipient was a 25-year-old woman weighing 46 kg. By 5 months post surgery, the serum creatinine level had gradually decreased to 1.47 mg/dL. In our experience, EBKT from preterm neonates <30 weeks' gestation and weighing <1.2 kg has demonstrated acceptable short- to medium-term results.

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.

A simple nomogram for predicting infectious diseases in adult kidney transplantation recipients.

Objective: To investigate the risk factors of infectious diseases in adult kidney transplantation recipients and to establish a simple and novel nomogram to guide the prophylactic antimicrobial therapy. Methods: Patients who received kidney transplantation between January 2018 and October 2021 were included in the study and were divided into a training and a testing set at a 1:1 ratio. Risk factors correlated to infectious diseases were selected using a Least Absolute Shrinkage and Selection Operator (LASSO) regression model. The prediction model was built by incorporating the variables selected by the LASSO model into a logistic regression equation. Calibration curves and receiver operating characteristic (ROC) curves were also applied to assess the model calibration and discrimination. A nomogram consisting of the selected factors was established to provide individualized risks of developing infections. Decision curve analysis (DCA) was adopted to estimate the net benefit and reduction in interventions for a range of clinically reasonable risk thresholds. Results: In all, 863 adult kidney recipients were included in the study, and 407 (47.16%) of them developed infectious diseases during the 3-year follow-up period. A total of 8 variables were selected using LASSO regression and were retained for subsequent model construction and infection prediction. The area under the curve (AUC) was 0.83 and 0.81 in the training and testing sets, with high F scores of 0.76 and 0.77, sensitivity of 0.76 and 0.81, and specificity of 0.88 and 0.74, respectively. A novel nomogram was developed based on 8 selected predictors (requirement for albumin infusion, requirement for red blood cell infusion, triglyceride, uric acid, creatinine, globulin, neutrophil percentage, and white blood cells). The net benefit indicated that the nomogram would reduce unnecessary interventions at a wide range of threshold probabilities in both sets. Conclusions: Adult kidney transplantation recipients are high-risk hosts for infectious diseases. The novel nomogram consisting of 8 factors reveals good predictive performance and may promote the reasonable antimicrobial prescription. More external validations are required to confirm its effectiveness for further clinical application.

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.

Inhibition of GSK-3ß induces AP-1-mediated osteopontin expression to promote cholestatic liver fibrosis.

The contribution of glycogen synthase kinase-3ß (GSK-3ß) to cholestatic liver disease (CLD) remains unknown. We investigated the role and mechanism of GSK-3ß in vivo in liver tissues of patients with CLD and the bile duct ligation (BDL) mouse model and in vitro using a hepatic progenitor cell (HPC) and hepatic stellate cell (HSC) coculture system. In liver tissues of patients with CLD, expression of the inactive form of GSK-3ß, phospho-GSK-3ß(Ser9), was increased in HPCs. GSK-3ß inhibition by SB216763 treatment aggravated liver fibrosis and elevated the expression of osteopontin (OPN) in the BDL mouse model. OPN was significantly overexpressed in liver tissues and serum from patients with CLD. In an HPC and HSC coculture system, inhibition of GSK-3ß induced OPN production, which activated HSCs in a cholestatic environment. The expression of activator protein 1 (AP-1), an important downstream transcription factor of GSK-3ß, was significantly increased in liver tissues of patients with CLD and SB216763-treated BDL mice. Finally, OPN expression was directly modulated by AP-1. These observations indicate that GSK-3ß inhibition up-regulates OPN expression via AP-1 activation, which accelerates the progression of cholestatic liver fibrosis in patients with CLD and in BDL mice.-Zhuang, S., Hua, X., He, K., Zhou, T., Zhang, J., Wu, H., Ma, X., Xia, Q., Zhang, J. Inhibition of GSK-3ß induces AP-1-mediated osteopontin expression to promote cholestatic liver fibrosis.