Diabetic nephropathy alters circulating long noncoding RNA levels that normalize following simultaneous pancreas-kidney transplantation

LncRNA H19 deficiency protects against the structural damage of glomerular endothelium in diabetic nephropathy via Akt/eNOS pathway

Objective: This study aimed to investigate the functions of lncRNA H19 on glomerular endothelial structural damage of diabetic nephropathy (DN).Materials and Methods: Rats were fed a high sugar and fat high feed die, and intraperitoneally administrated with streptozotocin (30 mg/kg) to induce DN model. Meanwile, rat glomerular endothelial cells (rGEnCs) were treated with high a level of glucose （HG, 30 mM glucose）to induce structural damage.Results: Our results showed that H19 level was drastically increased in diabetic glomeruli and high-glucose (HG)-stimulated rat glomerular endothelial cells (rGEnCs). Deficiency of H19 ameliorated microalbumin, creatinine, BUN, and histopathological alterations in diabetic rats. In addition, H19 deficiency significantly attenuated the damage of endothelial structure by upregulating the expression of junction proteins ZO-1 and Occludin, glycolcalyx protein Syndecan-1, and endothelial activation marker sVCAM-1 and sICAM-1 in diabetic rats. The in vitro results also showed that H19-siRNA alleviated glycocalyx shedding, tight junctions damage, and endothelial activation in HG-stimulated rGEnCs. Moreover, H19 deficiency significantly enhanced the expression of p-Akt and p-eNOS and NO concentration in vitro and in vivo. Pre-treatment with Akt inhibitor LY294002 abrogated these favourable effects mediated by H19 deficiency.Discussion and Conclusion: These results indicate that H19 deficiency could mitigate the structural damage of glomerular endothelium in DN via activating Akt/eNOS pathway.

Simultaneous pancreas-kidney transplantation for end-stage renal failure in type 1 diabetes mellitus: Current perspectives

Type 1 diabetes mellitus (T1DM) is one of the important causes of chronic kidney disease (CKD) and end-stage renal failure (ESRF). Even with the best available treatment options, management of T1DM poses significant challenges for cli nicians across the world, especially when associated with CKD and ESRF. Substantial increases in morbidity and mortality along with marked rise in treatment costs and marked reduction of quality of life are the usual consequences of onset of CKD and progression to ESRF in patients with T1DM. Simultaneous pancreas-kidney transplant (SPK) is an attractive and promising treatment option for patients with advanced CKD/ESRF and T1DM for potential cure of these diseases and possibly several complications. However, limited availability of the organs for transplantation, the need for long-term immunosuppression to prevent rejection, peri- and post-operative complications of SPK, lack of resources and the expertise for the procedure in many centers, and the cost implications related to the surgery and postoperative care of these patients are major issues faced by clinicians across the globe. This clinical update review compiles the latest evidence and current recommendations of SPK for patients with T1DM and advanced CKD/ESRF to enable clinicians to care for these diseases.

Circulating non-coding RNAs in chronic kidney disease and its complications

Post-transcriptional regulation by non-coding RNAs (ncRNAs) can modulate the expression of genes involved in kidney physiology and disease. A large variety of ncRNA species exist, including microRNAs, long non-coding RNAs, piwi-interacting RNAs, small nucleolar RNAs, circular RNAs and yRNAs. Despite early assumptions that some of these species may exist as by-products of cell or tissue injury, a growing body of literature suggests that these ncRNAs are functional and participate in a variety of processes. Although they function intracellularly, ncRNAs are also present in the circulation, where they are carried by extracellular vesicles, ribonucleoprotein complexes or lipoprotein complexes such as HDL. These systemic, circulating ncRNAs are derived from specific cell types and can be directly transferred to a variety of cells, including endothelial cells of the vasculature and virtually any cell type in the kidney, thereby affecting the function of the host cell and/or its response to injury. Moreover, chronic kidney disease itself, as well as injury states associated with transplantation and allograft dysfunction, is associated with a shift in the distribution of circulating ncRNAs. These findings may provide opportunities for the identification of biomarkers with which to monitor disease progression and/or the development of therapeutic interventions.

Identification of Renal Transplantation Rejection Biomarkers in Blood Using the Systems Biology Approach

Background

Renal transplantation plays an essential role in the quality of life of patients with end-stage renal disease. At least 12% of the renal patients receiving transplantations show graft rejection. One of the methods used to diagnose renal transplantation rejection is renal allograft biopsy. This procedure is associated with some risks such as bleeding and arteriovenous fistula formation. In this study, we applied a bioinformatics approach to identify serum markers for graft rejection in patients receiving a renal transplantation.

Methods

Transcriptomic data were first retrieved from the blood of renal transplantation rejection patients using the GEO database. The data were then used to construct the protein-protein interaction and gene regulatory networks using Cytoscape software. Next, network analysis was performed to identify hub-bottlenecks, and key blood markers involved in renal graft rejection. Lastly, the gene ontology and functional pathways related to hub-bottlenecks were detected using PANTHER and DAVID servers.

Results

In PPIN and GRN, SYNCRIP, SQSTM1, GRAMD1A, FAM104A, ND2, TPGS2, ZNF652, RORA, and MALAT1 were the identified critical genes. In GRN, miR-155, miR17, miR146b, miR-200 family, and GATA2 were the factors that regulated critical genes. The MAPK, neurotrophin, and TNF signaling pathways, IL-17, and human cytomegalovirus infection, human papillomavirus infection, and shigellosis were identified as significant pathways involved in graft rejection.

Concusion

The above-mentioned genes can be used as diagnostic and therapeutic serum markers of transplantation rejection in renal patients. The newly predicted biomarkers and pathways require further studies.

Potential Roles of Long Noncoding RNAs as Therapeutic Targets in Organ Transplantation

Organ transplantation is the most preferred treatment option for end-stage organ diseases; however, allograft rejection is the major hurdle in successful long-term transplant survival. In spite of developing better HLA matching and more effective immunosuppressive regimen, one-year graft survival has been increased by nearly 90% and the incidence of acute rejection by one-year post-transplantation has been decreased by 12.2% in the last decades, chronic allograft rejection has remained as one of the major obstacles to the long-lasting survival of the transplanted allograft. Therefore, seemingly preventing the allograft rejection and inducing immunological tolerance against transplanted allografts is one of the primary goals in transplantation research to enable long-lasting graft survival. Various mechanisms such as long noncoding RNAs (lncRNAs) have been proposed that induce immune tolerance by modulating the gene expression and regulating innate and adaptive immune responses during transplantation. Besides, because of involvement in regulating epigenetic, transcriptional, and post-translational mechanisms, lncRNAs could affect allograft status. Therefore, these molecules could be considered as the potential targets for prediction, prognosis, diagnosis, and treatment of graft rejection. It is suggested that the noninvasive predictive biomarkers hold promise to overcome the current limitations of conventional tissue biopsy in the diagnosis of rejection. Hence, this review aims to provide a comprehensive overview of lncRNAs and their function to facilitate diagnosis, prognosis, and prediction of the risk of graft rejection, and the suggestive therapeutic choices after transplantation.

Long noncoding RNA MIAT inhibits the progression of diabetic nephropathy and the activation of NF-κB pathway in high glucose-treated renal tubular epithelial cells by the miR-182-5p/GPRC5A axis

Background

Diabetic nephropathy (DN) is a common diabetic complication. Long noncoding RNAs (lncRNAs) have been identified as essential regulators in DN progression. This study is devoted to the research of lncRNA-myocardial infarction-associated transcript (MIAT) in DN.

Methods

DN cell model was established by high glucose (HG) treatment for human renal tubular epithelial cells (HK-2). Cell viability and colonizing capacity were analyzed by Cell Counting Kit-8 (CCK-8) and colony formation assay. Apoptosis was assessed via caspase-3 detection and flow cytometry. Enzyme-linked immunosorbent assay (ELISA) was used for evaluating inflammation. The protein determination was completed using western blot. MIAT, microRNA-182-5p (miR-182-5p), and G protein-coupled receptor class C group 5 member A (GPRC5A) levels were all examined via reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Intergenic binding was verified using dual-luciferase reporter, RNA immunoprecipitation (RIP), and RNA pull-down assays.

Results

HG induced the inhibition of cell growth, but accelerated apoptosis and inflammation as well as the activation of nuclear factor kappa B (NF-κB) pathway. MIAT reestablishment prevented the HG-induced cell damages and NF-κB signal activation. Mechanistically, MIAT was proved as a miR-182-5p sponge and regulated the expression of GPRC5A that was a miR-182-5p target. The rescued experiments demonstrated that MIAT downregulation or miR-182-5p upregulation aggravated the HG-induced cell damages and activated the NF-κB pathway via the respective regulation of miR-182-5p or GPRC5A.

Conclusion

Taken together, MIAT functioned as an inhibitory factor in the pathogenesis to impede the development of DN and inactivate the NF-κB pathway via regulating the miR-182-5p/GPRC5A axis.

Imaging the Renal Microcirculation in Cell Therapy

Renal microvascular rarefaction plays a pivotal role in progressive kidney disease. Therefore, modalities to visualize the microcirculation of the kidney will increase our understanding of disease mechanisms and consequently may provide new approaches for evaluating cell-based therapy. At the moment, however, clinical practice is lacking non-invasive, safe, and efficient imaging modalities to monitor renal microvascular changes over time in patients suffering from renal disease. To emphasize the importance, we summarize current knowledge of the renal microcirculation and discussed the involvement in progressive kidney disease. Moreover, an overview of available imaging techniques to uncover renal microvascular morphology, function, and behavior is presented with the associated benefits and limitations. Ultimately, the necessity to assess and investigate renal disease based on in vivo readouts with a resolution up to capillary level may provide a paradigm shift for diagnosis and therapy in the field of nephrology.

Reflections on the Role of Malat1 in Gynecological Cancer

Non-coding RNAs (ncRNAs) have received significant attention over the last few years. Malat1, as one of the most extensively studied ncRNAs, is believed to be not only a potential biomarker for disease diagnosis and prognosis, but also a candidate drug target for gynecological cancers. This potential is supported by a growing body of experimental evidence demonstrating that Malat1 participates in the occurrence, progression, and metastasis of tumors. Research has also shown that Malat1 can influence patient survival by regulating a range of target genes and signaling pathways. However, previous review articles have generally failed to consider the role of Malat1 in gynecological cancer in detail. In the present review, we summarize recent progress in research relating to the clinical relevance of Malat1 and the molecular mechanisms underlying the action of this ncRNA. Besides, we put forward some action points for further research after taking into consideration the sub-location and other essential properties of Malat1, which might enable us to have a better understanding of the potential of this molecule regarding clinical diagnosis and treatment.

Diabetic nephropathy alters circulating long noncoding RNA levels that normalize following simultaneous pancreas-kidney transplantation

Simultaneous pancreas-kidney transplantation (SPKT) replaces kidney function and restores endogenous insulin secretion in patients with diabetic nephropathy (DN). Here, we aimed to identify circulating long noncoding RNAs (lncRNAs) that are associated with DN and vascular injury in the context of SPKT. Based on a pilot study and a literature-based selection of vascular injury-related lncRNAs, we assessed 9 candidate lncRNAs in plasma samples of patients with diabetes mellitus with a kidney function >35 mL/min/1.73 m² (DM; n = 12), DN (n = 14), SPKT (n = 35), healthy controls (n = 15), and renal transplant recipients (KTx; n = 13). DN patients were also studied longitudinally before and 1, 6, and 12 months after SPKT. Of 9 selected lncRNAs, we found MALAT1, LIPCAR, and LNC-EPHA6 to be higher in DN compared with healthy controls. SPKT caused MALAT1, LIPCAR, and LNC-EPHA6 to normalize to levels of healthy controls, which was confirmed in the longitudinal study. In addition, we observed a strong association between MALAT1, LNC-EPHA6, and LIPCAR and vascular injury marker soluble thrombomodulin and a subset of angiogenic microRNAs (miR-27a, miR-130b, miR-152, and miR-340). We conclude that specific circulating lncRNAs associate with DN-related vascular injury and normalize after SPKT, suggesting that lncRNAs may provide a promising novel monitoring strategy for vascular integrity in the context of SPKT.

Circulating Long Noncoding RNA LNC-EPHA6 Associates with Acute Rejection after Kidney Transplantation

Acute rejection (AR) of a kidney graft in renal transplant recipients is associated with microvascular injury in graft dysfunction and, ultimately, graft failure. Circulating long noncoding RNAs (lncRNAs) may be suitable markers for vascular injury in the context of AR. Here, we first investigated the effect of AR after kidney transplantation on local vascular integrity and demonstrated that the capillary density markedly decreased in AR kidney biopsies compared to pre-transplant biopsies. Subsequently, we assessed the circulating levels of four lncRNAs (LNC-RPS24, LNC-EPHA6, MALAT1, and LIPCAR), that were previously demonstrated to associate with vascular injury in a cohort of kidney recipients with a stable kidney transplant function (n = 32) and recipients with AR (n = 15). The latter were followed longitudinally six and 12 months after rejection. We found higher levels of circulating LNC-EPHA6 during rejection, compared with renal recipients with a stable kidney function (p = 0.017), that normalized one year after AR. In addition, LNC-RPS24, LNC-EPHA6, and LIPCAR levels correlated significantly with the vascular injury marker soluble thrombomodulin. We conclude that AR and microvascular injury are associated with higher levels of circulating LNC-EPHA6, which emphasizes the potential role of lncRNAs as biomarker in the context of AR.