JAK inhibition and progressive kidney disease

Onconephrology: mitigation of renal injury in chemotherapy administration

PURPOSE OF REVIEW

Onconephrology was first coined as a name for the intersection of cancer medicine and nephrology in the early 2010s. It was recognized then that beyond and understanding of kidney physiology, a new generation of nephrologists skilled in both molecular biology and precision medicine were needed to deal with the challenges of emerging cancer therapies. Stem cell transplants, biologic agents, adjuvants blocking basic cellular signaling pathways, immunotherapy were found to promote novel anticancer outcomes, but also to pose new risks to the kidneys. The field rapidly overlapped with emerging expertise in vascular glomerular disease, glomerular disease, and the same biologic agents now applied to auto immune systemic and kidney diseases.

RECENT FINDINGS

Many categories of chemotherapeutic agents have been discovered to have adverse renal side effects. In this review, we address classic chemotherapeutic nephrotoxicity and oncologic clinical situations leading to acute kidney injury. We also review the frontiers of nephrotoxicity reported with cell cycle inhibitors, diverse classes of tyrosine kinase inhibitors, immune checkpoint inhibitors, chimeric antigen receptor T-cell therapy, anticancer vaccines, and thrombotic microangiopathies triggered by malignancy and chemotherapy. The aim will be to focus on published strategies to mitigate nephrotoxicity.

SUMMARY

As onconephrology expands into its own field, it gives birth to new subdisciplines. An understanding that patient populations want the benefits of chemotherapy without the renal (and other) systemic toxicities is emerging. A need to develop a new class of molecular and genetic experts in onconephrology to mitigate nephrotoxicity from chemotherapy is apparent and urgent.

Isoliquiritigenin attenuates high glucose-induced proliferation, inflammation, and extracellular matrix deposition in glomerular mesangial cells by suppressing JAK2/STAT3 pathway

To investigate the effect of isoliquiritigenin (ISL) on high glucose (HG)-induced glomerular mesangial cells (GMCs) proliferation, extracellular matrix (ECM) deposition and inflammation, and the underlying mechanisms. Mouse GMCs (SV40-MES-13) were cultured in HG medium, with or without ISL. The proliferation of GMCs was determined by MTT assay. The production of proinflammatory cytokines was detected by qRT-PCR and ELISA. The expression of connective tissue growth factor (CTGF), TGF-β1, collagen IV, and fibronectin was measured by qRT-PCR and western blot. The phosphorylation of JAK2 and STAT3 was examined by western blot. Next, JAK2 inhibitor AG490 was applied to HG-exposed GMCs. The levels of JAK2/STAT3 phosphorylation and pro-fibrotic markers were analyzed by western blot, and the secretion of TNF-α and IL-1β was evaluated by ELISA. GMCs were treated with HG, HG plus ISL or HG plus ISL, and recombinant IL-6 (rIL-6) which is a JAK2 activator. The levels of JAK2/STAT3 activation, ECM formation, and proinflammatory cytokines secretion were determined by western blot and ELISA, respectively. In mouse GMCs, ISL successfully repressed HG-induced hyperproliferation; production of TNF-α and IL-1β; expression of CTGF, TGF-β1, collagen IV, and fibronectin; and activation of JAK2/STAT3. Similar to ISL, AG490 was able to reverse the inflammation and ECM generation caused by HG. Moreover, rIL-6 impeded the amelioration of ISL on HG-induced adverse effects. Our study demonstrated that ISL displayed preventive effects on HG-exposed GMCs through inhibiting JAK2/STAT3 pathway and provided an insight into the application of ISL for diabetic nephropathy (DN) treatment.

SOCS1 Peptidomimetic Alleviates Glomerular Inflammation in MsPGN by Inhibiting Macrophage M1 Polarization

Mesangial proliferative glomerulonephritis (MsPGN), the most common pathological change in primary glomerulonephritis, is characterized by increased macrophage infiltration into glomeruli, which results in proinflammatory cytokine release. Macrophage infiltration and differentiation are induced by the Janus kinase 2 and signal transducer and activator of the transcription 1 (JAK2/STAT1) pathway. As a suppressor of cytokine signaling 1 (SOCS1) downregulates the immune response by inhibiting the JAK2/STAT1 pathway, we investigated whether a peptide mimicking the SOCS1 kinase inhibitor region, namely, SOCS1 peptidomimetic, protects against nephropathy. Glomerular JAK2/STAT1 pathway activation was synchronized with kidney injury in an MsPGN rat model. Rats treated with the SOCS1 peptidomimetic exhibited reduced pathological glomerular changes and lessened macrophage recruitment. Moreover, in vivo, the phosphorylation of the JAK2/STAT1 pathway was downregulated in infiltrated macrophages of glomeruli. In vitro, the SOCS1 peptidomimetic inhibited macrophage M1 polarization by suppressing JAK2/STAT1 activation. In conclusion, our study demonstrated that the SOCS1 peptidomimetic plays a protective role against pathologic glomerular changes in MsPGN by reducing macrophage infiltration and inhibiting macrophage polarizing to the M1 phenotype. SOCS1 peptidomimetic, therefore, presents a feasible therapeutic strategy to alleviate renal inflammation in MsPGN.

Profile of plasma free amino acids, carnitine and acylcarnitines, and JAK2v617f mutation as potential metabolic markers in children with type 1 diabetic nephropathy

Fifty diabetic nephropathy (DN) children with type 1 diabetes mellitus (T1DM) and 50 healthy matched controls were included. Chromatographic assays of 14 amino acids, free carnitine and 27 carnitine esters using high-performance liquid chromatography/electrospray ionization-mass spectroscopy, and genetic testing for JAK2v617f mutation using real-time PCR were performed. Patients had significantly lower levels of tyrosine, branched-chain amino acids (BCAAs), and BCAA/AAA (aromatic chain amino acids) ratios, glycine, arginine, ornithine, free carnitine and some carnitine esters (C5, 6, 12 and 16) and higher phenylalanine, phenylalanine/tyrosine ratio and C18 compared with the controls and in the macro-albuminuria vs. the microalbuminuria group (p < 0.05 for all) except for free carnitine. Plasma carnitine was negatively correlated with eGFR (r = -0.488, p = 0.000). There were significant positive correlations between tyrosine with UACR ratio (r = 0.296, p = 0.037). The plasma BCAA/AAA ratio showed significant negative correlations with UACR (r = -0.484, p = 0.000). There was a significantly higher frequency of the JAK2V617F gene mutation in diabetic nephropathy patients compared with the control group and in macro-albuminuria than the microalbuminuria group (p = 0.000) for both. When monitoring children with T1DM, plasma free amino acids and acylcarnitine profiles should be considered, especially if they have tested positive for JAK2V617F for the early diagnosis of DN.

JAK Inhibitors in Solid Organ Transplantation

Janus kinase (JAK) inhibitors are a novel group of immunosuppressive drugs approved to treat certain rheumatic and allergic disorders; however, their efficacy in the regulation of alloimmune responses after solid organ transplantation has not yet been elucidated. In the present review, we have summarized the results of in vitro, in vivo, experimental, and clinical trial studies about the efficacy and safety of JAK inhibitors in improving allograft survival in solid organ transplantations, including kidney, heart, lung, and liver transplants. Moreover, reports on administering JAK inhibitors to steroid-resistant patients with graft versus host disease (GvHD) after solid organ transplantation have been reviewed. Overall findings are suggestive of a beneficial role for JAK inhibitors in organ transplantation: for example, they have been shown to improve allograft function, reduce the rate and score of acute rejection, downregulate the expression of proinflammatory cytokines and adhesion molecules, and decrease oxidative stress. However, the adverse effects of these drugs, in particular bone marrow suppression and infection, remain an obstacle.

Comprehensive analysis of the relationship between xanthine oxidoreductase activity and chronic kidney disease

Chronic kidney disease (CKD) is a common disease that seriously endangers human health. However, the potential relationship between xanthine oxidoreductase (XOR) activity and CKD remains unclear. In this study, we used clinical data, CKD datasets from the Gene Expression Omnibus database, and untargeted metabolomics to explain the relationship between XOR activity and CKD. First, XOR activity showed high correlation with the biomarkers of CKD, such as serum creatinine, blood urea nitrogen, uric acid, and estimated glomerular filtration rate. Then, we used least absolute shrinkage and selection operator logical regression algorithm and random forest algorithm to screen CKD molecular markers from differentially expressed genes, and the results of qRT-PCR of XDH, KOX-1, and ROMO1 were in accordance with the results of bioinformatics analyses. In addition, untargeted metabolomics analysis revealed that the purine metabolism pathway was significantly enriched in CKD patients in the simulated models of kidney fibrosis.

Novel Therapies in APOL1-Mediated Kidney Disease: From Molecular Pathways to Therapeutic Options

Apolipoprotein L1 (APOL1) high-risk variants confer an increased risk for the development and progression of kidney disease among individuals of recent African ancestry. Over the past several years, significant progress has been made in understanding the pathogenesis of APOL1-mediated kidney diseases (AMKD), including genetic regulation, environmental interactions, immunomodulatory, proinflammatory and apoptotic signaling processes, as well as the complex role of APOL1 as an ion channel. Collectively, these findings have paved the way for novel therapeutic strategies to mitigate APOL1-mediated kidney injury. Precision medicine approaches are being developed to identify subgroups of AMKD patients who may benefit from these targeted interventions, fueling hope for improved clinical outcomes. This review summarizes key mechanistic insights in the pathogenesis of AMKD, emergent therapies, and discusses future challenges.

AAV-SPL 2.0, a Modified Adeno-Associated Virus Gene Therapy Agent for the Treatment of Sphingosine Phosphate Lyase Insufficiency Syndrome

Sphingosine-1-phosphate lyase insufficiency syndrome (SPLIS) is an inborn error of metabolism caused by inactivating mutations in SGPL1, the gene encoding sphingosine-1-phosphate lyase (SPL), an essential enzyme needed to degrade sphingolipids. SPLIS features include glomerulosclerosis, adrenal insufficiency, neurological defects, ichthyosis, and immune deficiency. Currently, there is no cure for SPLIS, and severely affected patients often die in the first years of life. We reported that adeno-associated virus (AAV) 9-mediated SGPL1 gene therapy (AAV-SPL) given to newborn Sgpl1 knockout mice that model SPLIS and die in the first few weeks of life prolonged their survival to 4.5 months and prevented or delayed the onset of SPLIS phenotypes. In this study, we tested the efficacy of a modified AAV-SPL, which we call AAV-SPL 2.0, in which the original cytomegalovirus (CMV) promoter driving the transgene is replaced with the synthetic "CAG" promoter used in several clinically approved gene therapy agents. AAV-SPL 2.0 infection of human embryonic kidney (HEK) cells led to 30% higher SPL expression and enzyme activity compared to AAV-SPL. Newborn Sgpl1 knockout mice receiving AAV-SPL 2.0 survived ≥ 5 months and showed normal neurodevelopment, 85% of normal weight gain over the first four months, and delayed onset of proteinuria. Over time, treated mice developed nephrosis and glomerulosclerosis, which likely resulted in their demise. Our overall findings show that AAV-SPL 2.0 performs equal to or better than AAV-SPL. However, improved kidney targeting may be necessary to achieve maximally optimized gene therapy as a potentially lifesaving SPLIS treatment.

COL4A3 Mutation Induced Podocyte Apoptosis by Dysregulation of NADPH Oxidase 4 and MMP-2

Introduction

Podocyte apoptosis is a common mechanism driving progression in Alport syndrome (AS). This study aimed to investigate the mechanism of podocyte apoptosis caused by COL4A3 mutations.

Methods

We recruited patients with autosomal dominant AS (ADAS). Patients with minimal change disease (MCD) were recruited as controls. Microarray analysis was carried out on isolated glomeruli from the patients and validated. Then, corresponding mutant human podocytes (p.C1616Y) and 129 mice (p.C1615Y, the murine homolog to the human p.C1616Y) were constructed. The highest differentially expressed genes (DEGs) from microarray analysis were validated in transgenic mice and podocytes before and after administration of MMP-2 inhibitor (SB-3CT) and NOX4 inhibitor (GKT137831). We further validated NOX4/MMP-2/apoptosis pathway by real-time polymerase chain reaction (PCR), immunohistochemistry, and western blot in renal tissues from the ADAS patients.

Results

Using microarray analysis, we observed that DEGs, including NOX4/H2O2, MMP-2, and podocyte apoptosis-related genes were significantly upregulated. These genes were validated by real-time PCR, histologic analysis, and western blot in corresponding mutant human podocyte (p.C1616Y) and/or mice models (p.C1615Y). Moreover, we found podocyte apoptosis was abrogated and MMP-2 expression was down-regulated both in vivo and in vitro by NOX4 inhibition, urinary albumin-to-creatinine ratio, 24-hour proteinuria; and renal pathologic lesion was attenuated by NOX4 inhibition in vivo. Furthermore, podocyte apoptosis was attenuated whereas NOX4 expression remained the same by inhibition of MMP-2 both in vivo and in vitro.

Conclusion

These results indicated that NOX4 might induce podocyte apoptosis through the regulation of MMP-2 in patients with COL4A3 mutations. Our findings provided new insights into the mechanism of ADAS.

Dysregulated phosphate metabolism in autism spectrum disorder: associations and insights for future research

Studies of autism spectrum disorder (ASD) related to exposure to toxic levels of dietary phosphate are lacking. Phosphate toxicity from dysregulated phosphate metabolism can negatively impact almost every major organ system of the body, including the central nervous system. The present paper used a grounded theory-literature review method to synthesise associations of dysregulated phosphate metabolism with the aetiology of ASD. Cell signalling in autism has been linked to an altered balance between phosphoinositide kinases, which phosphorylate proteins, and the counteracting effect of phosphatases in neuronal membranes. Glial cell overgrowth in the developing ASD brain can lead to disturbances in neuro-circuitry, neuroinflammation and immune responses which are potentially related to excessive inorganic phosphate. The rise in ASD prevalence has been suggested to originate in changes to the gut microbiome from increasing consumption of additives in processed food, including phosphate additives. Ketogenic diets and dietary patterns that eliminate casein also reduce phosphate intake, which may account for many of the suggested benefits of these diets in children with ASD. Dysregulated phosphate metabolism is causatively linked to comorbid conditions associated with ASD such as cancer, tuberous sclerosis, mitochondrial dysfunction, diabetes, epilepsy, obesity, chronic kidney disease, tauopathy, cardiovascular disease and bone mineral disorders. Associations and proposals presented in this paper offer novel insights and directions for future research linking the aetiology of ASD with dysregulated phosphate metabolism and phosphate toxicity from excessive dietary phosphorus intake.

Integrated Analysis of Single-Cell RNA-Seq and Bulk RNA-Seq Combined with Multiple Machine Learning Identified a Novel Immune Signature in Diabetic Nephropathy

Background

Increasing evidence suggests that immune modulation contributes to the pathogenesis and progression of diabetic nephropathy (DN). However, the role of immune modulation in DN has not been elucidated. The purpose of this study was to search for potential immune-related therapeutic targets and molecular mechanisms of DN.

Methods

Gene expression datasets were obtained from the Gene Expression Omnibus (GEO) database. A total of 1793 immune-related genes were acquired from the Immunology Database and Analysis Portal (ImmPort). Weighted gene co-expression network analysis (WGCNA) was performed for GSE142025, and the red and turquoise co-expression modules were found to be key for DN progression. We utilized four machine learning algorithms, namely, random forest (RF), support vector machine (SVM), adaptive boosting (AdaBoost), and k-nearest neighbor (KNN), to evaluate the diagnostic value of hub genes. Immune infiltration patterns were analyzed using the CIBERSORT algorithm, and the correlation between immune cell type abundance and hub gene expression was also investigated.

Results

A total of 77 immune-related genes of advanced DN were selected for subsequent analyzes. Functional enrichment analysis showed that the regulation of cytokine-cytokine receptor interactions and immune cell function play a corresponding role in the progression of DN. The final 10 hub genes were identified through multiple datasets. In addition, the expression levels of the identified hub genes were corroborated through a rat model. The RF model exhibited the highest AUC. CIBERSORT analysis and single-cell sequencing analysis revealed changes in immune infiltration patterns between control subjects and DN patients. Several potential drugs to reverse the altered hub genes were identified through the Drug-Gene Interaction database (DGIdb).

Conclusion

This pioneering work provided a novel immunological perspective on the progression of DN, identifying key immune-related genes and potential drug targets, thus stimulating future mechanistic research and therapeutic target identification for DN.

Huangkui capsule alleviates doxorubicin-induced proteinuria via protecting against podocyte damage and inhibiting JAK/STAT signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Huangkui capsule (HKC), a Chinese patent medicine, has been widely used in China as adjuvant therapy for chronic kidney disease (CKD). It displays superior anti-proteinuria efficacy than losartan in patients with CKD at stages 1-2, however, the mechanism of HKC alleviating proteinuria has not been well elucidated.

AIM OF THE STUDY

This study aims to confirm the therapeutic effect and investigate associated underlying mechanism of HKC against proteinuria by in vivo and in vitro experiments.

MATERIALS AND METHODS

We established a doxorubicin (DOX) induced proteinuria mouse model to evaluate kidney function by biochemical markers measurement and to observe histopathological alterations by hematoxylin and eosin (H&E), Masson's trichrome and Periodic Acid-Schiff (PAS)-stained sections of renal, respectively. Moreover, the expressions of Nephrin and Podocin were measured by immunohistochemistry (IHC) and western blotting analysis to investigate podocyte damage. Furthermore, we established Mouse Podocyte Clone-5 (MPC-5) injury model to identify the active components of HKC against podocyte damage by detecting the expressions of Nephrin, Podocin, and ZO-1 proteins. At last, the key protein levels of Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway were assessed by western blotting analysis to explore the underlying mechanism of HKC against proteinuria.

RESULTS

Our results showed that HKC administration for three consecutive weeks dose-dependently ameliorated both renal function and histopathological damages, elevated the expressions of Nephrin and Podocin, the pivotal molecules maintaining filtration function of the podocyte, indicating the promising protective effect against podocyte injury under DOX exposure. Consistently, in vitro experiments showed HKC administration effectively reversed the abnormal expressions of Nephrin and Podocin in MPC-5 cells treated with DOX, suggesting its protective effect against podocyte injury to maintain filtration barrier integrity. In addition, Hibifolin was identified as the most active ingredients in HKC, which suppressed upstream JAK2/STAT3 and PI3K/Akt pathway phosphorylation to maintain the structural and functional integrity of podocyte filtration barrier. Of note, AG490, a selective JAK2 inhibitor, was used to further affirm the role of Hibifolin involving in regulation JAK2/STAT3.

CONCLUSIONS

Our study suggested that HKC may protect podocytes via JAK2/STAT3 and PI3K/Akt pathway to display its effects of ameliorating proteinuria.

Effect of Bining decoction on gouty nephropathy: a network pharmacology analysis and preliminary validation of gut microbiota in a mouse model

Background

To use network pharmacology and gut microbiota sequencing to investigate the probable mechanism of Bining decoction (BN) in the treatment of gouty nephropathy (GN).

Methods

Firstly, the mechanism of therapeutic effects of BN on GN were collected by integrating network pharmacology. Secondly, the treatment effects of BN against GN in 30 Institute of Cancer Research (ICR) mice were evaluated by performing biochemical tests [uric acid, blood urea nitrogen, and creatinine (UA, BUN, and Cr)] and evaluating the renal weight index. Finally, 16S rRNA sequencing was utilized for elucidating the therapeutical effect of BN in GN.

Results

The results of gut microbiota sequencing analysis showed the abundance of Faecalibaculum, Romboutsia, Bifidobacterium, Bacteroides, Odoribacter, Lachnospiraceae NK4A136 group, unclassified_f__Lachnospiraceae, Roseburia, norank_f__Lachnospiraceae, Lactobacillus, Dubosiella, norank_f__Muribaculaceae, and Turicibacter in the BN group had a significant changed between-group comparisons. Using a network pharmacology-related database, 413 active components of BN were identified, as well as 1,085 GN-associated targets. The 118 targets of disease targets and component targets were mapped, of which the top 10 genes were selected. The Kyoto Encyclopedia of Genes and Genomes (KEGG) results showed that 157 pathways were enriched, which was partially consistent with the metabolic pathways of gut microbiota sequencing analysis.

Conclusions

Combining 16S rRNA gene sequencing and network pharmacology analysis, similar signaling pathways were followed: "Pathways in cancer" and "Adipocytokine signaling pathway". The results reveal that BN increases the abundance of Turicibacter, regulates the expression of JAK2 in the JAK/STAT pathway, increases the beneficial bacteria Turicibacter associated with intestinal butyric acid, which could enhance the intestinal barrier, and exert anti-inflammatory effects.

pSTAT1 Is Activated during the Progression of IgA Nephropathy

Introduction

IgA nephropathy is the most common primary glomerular disease. Its pathogenesis is still poorly understood. Alterations of the Janus kinase signal transducer and activator of transcription (JAK-STAT) pathway may play an important role in IgA nephropathy.

Methods

We evaluated the clinical features, pathology, and tissue staining for lymphocytes and phosphorylated STAT1 (pSTAT1) in 43 patients with biopsy proven IgA nephropathy. They were followed to determine their disease outcomes. All had biopsy tissue and multiple laboratory measurements to assess their kidney disease progression. Sixteen patients underwent repeat kidney biopsy to further assess their clinical status.

Results

The median eGFR at baseline was 61 mL/min/1.73 m² and the median proteinuria was 2,600 mg/d. The median follow-up was 5 years with an average annual decline in eGFR of 2.25 mL/min/1.73 m². There was significant inflammation and atrophy seen in the first biopsy, which progressed among those who undertook a 2nd biopsy. Compared to healthy kidney tissue, glomeruli and tubulointerstitium demonstrated increased lymphocyte (CD3+) infiltrates and increased pSTAT1 staining by immunohistochemistry. Increased CD3 (p = 0.001) staining and increased pSTAT1 (p = 0.03) correlated with reduced eGFR levels. In repeat biopsy samples, increasing pSTAT1 staining correlated with loss of eGFR over time (p = 0.02).

Conclusion

These findings support the hypothesis that pSTAT1 is activated in IgA nephropathy and may play a role in the progression toward kidney failure.

Signaling pathways of chronic kidney diseases, implications for therapeutics

Chronic kidney disease (CKD) is a chronic renal dysfunction syndrome that is characterized by nephron loss, inflammation, myofibroblasts activation, and extracellular matrix (ECM) deposition. Lipotoxicity and oxidative stress are the driving force for the loss of nephron including tubules, glomerulus, and endothelium. NLRP3 inflammasome signaling, MAPK signaling, PI3K/Akt signaling, and RAAS signaling involves in lipotoxicity. The upregulated Nox expression and the decreased Nrf2 expression result in oxidative stress directly. The injured renal resident cells release proinflammatory cytokines and chemokines to recruit immune cells such as macrophages from bone marrow. NF-κB signaling, NLRP3 inflammasome signaling, JAK-STAT signaling, Toll-like receptor signaling, and cGAS-STING signaling are major signaling pathways that mediate inflammation in inflammatory cells including immune cells and injured renal resident cells. The inflammatory cells produce and secret a great number of profibrotic cytokines such as TGF-β1, Wnt ligands, and angiotensin II. TGF-β signaling, Wnt signaling, RAAS signaling, and Notch signaling evoke the activation of myofibroblasts and promote the generation of ECM. The potential therapies targeted to these signaling pathways are also introduced here. In this review, we update the key signaling pathways of lipotoxicity, oxidative stress, inflammation, and myofibroblasts activation in kidneys with chronic injury, and the targeted drugs based on the latest studies. Unifying these pathways and the targeted therapies will be instrumental to advance further basic and clinical investigation in CKD.

Complete remission of tip lesion variant focal segmental glomerulosclerosis (FSGS) with the Janus Kinase (JAK) inhibitor tofacitinib

A 67-year-old woman with transverse myelitis and seizure disorder secondary to suspected central nervous system (CNS) systemic lupus erythematosus (SLE) and seropositive rheumatoid arthritis had two episodes of severe nephrotic syndrome 15 years apart. She underwent a renal biopsy in both episodes, showing tip lesion variant focal segmental glomerulosclerosis (FSGS). The patient responded both times to prednisone treatment, achieving a complete remission within 2 months in the first episode and remission 4 months in the second episode. A year after her second episode, the patient had a third episode of severe nephrotic syndrome. She achieved an equally rapid complete remission in 3 months without steroid treatment, as she was concomitantly treated with the Janus Kinase (JAK) inhibitor tofacitinib for a flare of rheumatoid arthritis. This case report suggests that JAK inhibitors may have therapeutic use in FSGS, which is supported by experimental data in the medical literature.

Involvement of NOX-4/JAK/STAT pathway in the protective effect of aprepitant against diclofenac-induced renal toxicity

AIMS

Aprepitant, a neurokinin-1 (NK1) receptor antagonist, is a clinically approved anti-emetic drug. Recently, inhibition of the NK1 receptor has been reported as a potential nephroprotective strategy. We aimed to assess the pharmacological mechanisms of aprepitant against diclofenac (DIC)-induced renal toxicity.

MAIN METHODS

An in vivo study was conducted using twenty-four male Wistar rats, divided into 4 groups. Aprepitant was administered for 5 days (5 mg/kg/day) with or without DIC which was given on the 4th and 5th days (50 mg/kg, i.p.). At the end of the study, renal function biomarkers, renal oxidative parameters, prostaglandin E (PGE-2), and NADPH oxidase (NOX-4) were measured. Histopathological changes as well as expression of renal inflammatory and apoptotic markers (tumor necrosis factor alpha (TNF-α) and caspase-3) were investigated.

KEY FINDINGS

DIC caused significant renal damage, as evidenced by deterioration of renal functions, oxidative stress, inflammatory and apoptotic markers, and confirmed by histopathological findings. Pretreatment with aprepitant successfully ameliorated and improved all biochemical and molecular parameters induced by DIC. Moreover, aprepitant restored the decrease in renal PGE-2 concentration and inhibited DIC-activated Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling in renal tissues.

SIGNIFICANCE

The protective effect of aprepitant is possibly attributed to its anti-oxidant and anti-inflammatory roles via the NOX-4/JAK/STAT pathway.

Activation of STAT3 signaling pathway in the kidney of COVID-19 patients

Background

Acute kidney injury is common in patients with COVID-19, however mechanisms of kidney injury remain unclear. Since cytokine storm is likely a cause of AKI and glomerular disease, we investigated the two major transcription factors, STAT3 and NF-kB, which are known to be activated by cytokines.

Methods

This is an observational study of the postmortem kidneys of 50 patients who died with COVID-19 in the Mount Sinai Hospital during the first pandemic surge. All samples were reviewed under light microscopy, electron microscopy, and immunofluorescence by trained renal pathologists. In situ hybridization evaluation for SARS-CoV-2 and immunostaining of transcription factors STAT3 and NF-kB were performed.

Results

Consistent with previous findings, acute tubular injury was the major pathological finding, together with global or focal glomerulosclerosis. We were not able to detect SARS-CoV-2 in kidney cells. ACE2 expression was reduced in the tubular cells of patients who died with COVID-19 and did not co-localize with TMPRSS2. SARS-CoV-2 was identified occasionally in the mononuclear cells in the peritubular capillary and interstitium. STAT3 phosphorylation at Tyr705 was increased in 2 cases in the glomeruli and in 3 cases in the tubulointerstitial compartments. Interestingly, STAT3 phosphorylation at Ser727 increased in 9 cases but only in the tubulointerstitial compartment. A significant increase in NF-kB phosphorylation at Ser276 was also found in the tubulointerstitium of the two patients with increased p-STAT3 (Tyr705).

Conclusions

Our findings suggest that, instead of tyrosine phosphorylation, serine phosphorylation of STAT3 is commonly activated in the kidney of patients with COVID-19.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40620-021-01173-0.

Human Liver Stem Cell Derived Extracellular Vesicles Alleviate Kidney Fibrosis by Interfering with the β-Catenin Pathway through miR29b

Human liver stem-cell-derived extracellular vesicles (HLSC-EVs) exhibit therapeutic properties in various pre-clinical models of kidney injury. We previously reported an overall improvement in kidney function following treatment with HLSC-EVs in a model of aristolochic acid nephropathy (AAN). Here, we provide evidence that HLSC-EVs exert anti-fibrotic effects by interfering with β-catenin signalling. A mouse model of AAN and an in vitro pro-fibrotic model were used. The β-catenin mRNA and protein expression, together with the pro-fibrotic markers α-SMA and collagen 1, were evaluated in vivo and in vitro following treatment with HLSC-EVs. Expression and functional analysis of miR29b was performed in vitro following HLSC-EV treatments through loss-of-function experiments. Results showed that expression of β-catenin was amplified both in vivo and in vitro, and β-catenin gene silencing in fibroblasts prevented AA-induced up-regulation of pro-fibrotic genes, revealing that β-catenin is an important factor in fibroblast activation. Treatment with HLSC-EVs caused increased expression of miR29b, which was significantly inhibited in the presence of α-amanitin. The suppression of the miR29b function with a selective inhibitor abolished the anti-fibrotic effects of HLSC-EVs, resulting in the up-regulation of β-catenin and pro-fibrotic α-Sma and collagen type 1 genes. Together, these data suggest a novel HLSC-EV-dependent regulatory mechanism in which β-catenin is down regulated by HLSC-EVs-induced miR29b expression.

Interplay between extracellular matrix components and cellular and molecular mechanisms in kidney fibrosis

Chronic kidney disease (CKD) is characterized by pathological accumulation of extracellular matrix (ECM) proteins in renal structures. Tubulointerstitial fibrosis is observed in glomerular diseases as well as in the regeneration failure of acute kidney injury (AKI). Therefore, finding antifibrotic therapies comprises an intensive research field in Nephrology. Nowadays, ECM is not only considered as a cellular scaffold, but also exerts important cellular functions. In this review, we describe the cellular and molecular mechanisms involved in kidney fibrosis, paying particular attention to ECM components, profibrotic factors and cell-matrix interactions. In response to kidney damage, activation of glomerular and/or tubular cells may induce aberrant phenotypes characterized by overproduction of proinflammatory and profibrotic factors, and thus contribute to CKD progression. Among ECM components, matricellular proteins can regulate cell-ECM interactions, as well as cellular phenotype changes. Regarding kidney fibrosis, one of the most studied matricellular proteins is cellular communication network-2 (CCN2), also called connective tissue growth factor (CTGF), currently considered as a fibrotic marker and a potential therapeutic target. Integrins connect the ECM proteins to the actin cytoskeleton and several downstream signaling pathways that enable cells to respond to external stimuli in a coordinated manner and maintain optimal tissue stiffness. In kidney fibrosis, there is an increase in ECM deposition, lower ECM degradation and ECM proteins cross-linking, leading to an alteration in the tissue mechanical properties and their responses to injurious stimuli. A better understanding of these complex cellular and molecular events could help us to improve the antifibrotic therapies for CKD.

Kidney Dysfunction Is Associated with Thrombosis and Disease Severity in Myeloproliferative Neoplasms: Implications from the German Study Group for MPN Bioregistry

Simple Summary

In patients with myeloproliferative neoplasms (MPN) and in patients with kidney dysfunction, a higher rate of thrombosis has been reported compared with the general population. Furthermore, MPN patients are more prone to develop kidney dysfunction. In our study, we assessed the importance of specific risk factors for kidney dysfunction and thrombosis in MPN patients. We found that the rate of thrombosis is correlated with the degree of kidney dysfunction, especially in myelofibrosis. Significant associations for kidney dysfunction included arterial hypertension, MPN treatment, and increased inflammation, and those for thrombosis comprised arterial hypertension, non-excessive platelet counts, and antithrombotic therapy. The identified risk factor associations varied between MPN subtypes. Our data suggest that kidney dysfunction in MPN patients is associated with an increased risk of thrombosis, mandating closer monitoring, and, possibly, early thromboprophylaxis.

Abstract

Inflammation-induced thrombosis represents a severe complication in patients with myeloproliferative neoplasms (MPN) and in those with kidney dysfunction. Overlapping disease-specific attributes suggest common mechanisms involved in MPN pathogenesis, kidney dysfunction, and thrombosis. Data from 1420 patients with essential thrombocythemia (ET, 33.7%), polycythemia vera (PV, 38.5%), and myelofibrosis (MF, 27.9%) were extracted from the bioregistry of the German Study Group for MPN. The total cohort was subdivided according to the calculated estimated glomerular filtration rate (eGFR, (mL/min/1.73 m²)) into eGFR1 (≥90, 21%), eGFR2 (60–89, 56%), and eGFR3 (<60, 22%). A total of 29% of the patients had a history of thrombosis. A higher rate of thrombosis and longer MPN duration was observed in eGFR3 than in eGFR2 and eGFR1. Kidney dysfunction occurred earlier in ET than in PV or MF. Multiple logistic regression analysis identified arterial hypertension, MPN treatment, increased uric acid, and lactate dehydrogenase levels as risk factors for kidney dysfunction in MPN patients. Risk factors for thrombosis included arterial hypertension, non-excessive platelet counts, and antithrombotic therapy. The risk factors for kidney dysfunction and thrombosis varied between MPN subtypes. Physicians should be aware of the increased risk for kidney disease in MPN patients, which warrants closer monitoring and, possibly, early thromboprophylaxis.

Advances in understanding the innate immune-associated diabetic kidney disease

Millions of human deaths occur annually due to chronic kidney disease, caused by diabetic kidney disease (DKD). Despite having effective drugs controlling the hyperglycemia and high blood pressure, the incidence of DKD is increasing, which indicates the need for the development of novel therapies to control DKD. In this article, we discussed the recent advancements in the basic innate immune mechanisms in renal tissues triggered under the diabetes environment, leading to the pathogenesis and progression of DKD. We also summarized the currently available innate immune molecules-targeting therapies tested against DKD in clinical and preclinical settings, and highlighted additional drug targets that could potentially be employed for the treatment of DKD. The improved understanding of the disease pathogenesis may open avenues for the development of novel therapies to rein in DKD, which consequently, can reduce morbidity and mortality in humans in the future.

Interleukin-6 Signaling and Anti-Interleukin-6 Therapeutics in Cardiovascular Disease

IL (interleukin)-6 is a pivotal cytokine of innate immunity, which enacts a broad set of physiological functions traditionally associated with host defense, immune cell regulation, proliferation, and differentiation. Following recognition of innate immune pathways leading from the NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) inflammasome to IL-1 to IL-6 and on to the hepatically derived clinical biomarker CRP (C-reactive protein), an expanding literature has led to understanding of the proatherogenic role for IL-6 in cardiovascular disease and thus the potential for IL-6 inhibition as a novel method for vascular protection. In this review, we provide an overview of the mechanisms by which IL-6 signaling occurs and how that impacts upon pharmacological inhibition; describe murine models of IL-6 and atherogenesis; summarize human epidemiological data outlining the utility of IL-6 as a biomarker of vascular risk; outline genetic data suggesting a causal role for IL-6 in systemic atherothrombosis and aneurysm formation; and then detail the potential role of IL-6 inhibition in stable coronary disease, acute coronary syndromes, heart failure, and the atherothrombotic complications associated with chronic kidney disease and end-stage renal failure. Finally, we review anti-inflammatory and antithrombotic findings for ziltivekimab, a novel IL-6 ligand inhibitor being developed specifically for use in atherosclerotic disease and poised to be tested formally in a large-scale cardiovascular outcomes trial focused on individuals with chronic kidney disease and elevated levels of CRP, a population at high residual atherothrombotic risk, high residual inflammatory risk, and considerable unmet clinical need.

Renoprotective Effect of the Recombinant Anti-IL-6R Fusion Proteins by Inhibiting JAK2/STAT3 Signaling Pathway in Diabetic Nephropathy

Diabetic nephropathy the main reason for end stage renal disease is a common microvascular complication in patients with type 1 and type 2 diabetes. The interleukin-6 (IL-6), acting as a pleiotropic cytokine, play key roles in main autoimmune disorders. The recombinant anti-IL-6R fusion proteins (VHH-0031) constructed and obtained in our lab is a dual target-directed single domain-based fusion protein against the interleukin-6 receptor. This study aims to explore the renoprotective effect of VHH-0031 in diabetic nephropathy. VHH-0031 treatment alleviated renal inflammation, morphologic injury and renal insufficiency in both Goto-Kakizaki rats and STZ-induced Sprague Dawley rats. These renoprotective effects of VHH-0031 are associated with alleviating inflammation and suppression of the JAK2/STAT3 signaling pathway. The mesangial cells treated with VHH-0031 exhibited anti-proliferation, anti-inflammation and inactivation of JAK2/STAT3 pathway under high glucose condition. In conclusion, this study demonstrates that VHH-0031 exhibited a potent protective effect in kidney of diabetic rats and its mechanism may be concerned with the inhibition of the IL-6R/JAK2/STAT3 pathway of glomerular mesangial cells.

Pathophysiology of diabetic kidney disease: impact of SGLT2 inhibitors

Diabetic kidney disease is the leading cause of kidney failure worldwide; in the USA, it accounts for over 50% of individuals entering dialysis or transplant programmes. Unlike other complications of diabetes, the prevalence of diabetic kidney disease has failed to decline over the past 30 years. Hyperglycaemia is the primary aetiological factor responsible for the development of diabetic kidney disease. Once hyperglycaemia becomes established, multiple pathophysiological disturbances, including hypertension, altered tubuloglomerular feedback, renal hypoxia, lipotoxicity, podocyte injury, inflammation, mitochondrial dysfunction, impaired autophagy and increased activity of the sodium-hydrogen exchanger, contribute to progressive glomerular sclerosis and the decline in glomerular filtration rate. The quantitative contribution of each of these abnormalities to the progression of diabetic kidney disease, as well as their role in type 1 and type 2 diabetes mellitus, remains to be determined. Sodium-glucose co-transporter 2 (SGLT2) inhibitors have a beneficial impact on many of these pathophysiological abnormalities; however, as several pathophysiological disturbances contribute to the onset and progression of diabetic kidney disease, multiple agents used in combination will likely be required to slow the progression of disease effectively.

Understanding glomerular diseases through proteomics

INTRODUCTION

Chronic kidney disease is avery common and complex chronic disease. Uncovering the pathological patterns of CKD on the molecular level of bio-fluids and tissue appears to be both vital and promising for a more favorable outcome. We reviewed recently discovered proteomics biomarkers for CKD to provide new insight into disease pathology.

AREAS COVERED

We review the application of proteome analysis in the context of CKD with various etiologies within the last 5 years. Proteins and peptides associated with CKD as derived from multiple sources (urine, blood and tissue) are reported along with their various biological pathways.

EXPERT OPINION

A systematic and theoretical comprehension of the CKD pathology is essential for its successful management. The underlying complexity of the disease further requires specific conditions for reliable and interpretable results. In this context, clinical proteomics has resulted in first encouraging findings in CKD. A more complete understanding of the biological pathways related to the disease, based on the scope of a holistic proteomic approach, could improve substantially the management of CKD, especially when in conjunction with the current trend of personalized medicine.

LncRNA NEAT1 Promotes High Glucose-Induced Mesangial Cell Hypertrophy by Targeting miR-222-3p/CDKN1B Axis

Glomerular hypertrophy is an early morphological alteration in diabetic nephropathy. Cyclin-Dependent Kinases have been shown to be required for high glucose (HG)-induced hypertrophy; however, the upstream regulators of CDKN1B in glomerular hypertrophy remain unclear. Herein we describe a novel pathway in which Long noncoding RNA (lncRNA) NEAT1 regulates the progression of mesangial cell hypertrophy via a competing endogenous RNA (ceRNA) mechanism. Real-time PCR was performed to detect the relative NEAT1 and miR-222-3p expressions and further confirmed the relationship between NEAT1 and miR-222-3p. Cell cycle was evaluated by flow cytometry. The related mechanisms were explored by Western blot, RNA immunoprecipitation and chromatin immunoprecipitation assay. We show that NEAT1 forms double stranded RNA (dsRNA) with miR-222-3p, thus limiting miR-222-3p's binding with CDKN1B. This release of CDKN1B mRNA leads to elevated CDKN1B protein expression, resulting in hypertrophy. In addition, we demonstrated that STAT3 which is activated by HG induces the transcription of NEAT1 by binding to its promoter. Our findings underscore an unexpected role of lncRNAs on gene regulation and introduce a new mode of proliferation regulation in mesangial cells.

Neuroprotective effects of vildagliptin on drug induced Alzheimer's disease in rats with metabolic syndrome: Role of hippocampal klotho and AKT signaling pathways

Growing evidences suggest the presence of several similarities in the molecular mechanisms underlying the neurodegenerative diseases and metabolic abnormalities. Adults who develop Metabolic Syndrome (MS) are at a higher risk of developing Alzheimer's disease (AD). Pharmacological agents, like dipeptidyl peptidase-4 (DPP-4) inhibitors that increase the levels of glucagon like peptide 1 (GLP-1) and ameliorate symptoms of MS, have become an auspicious candidate as disease modifying agents in the treatment of AD. The present study investigates the beneficial effects of Vildagliptin, a DPP-4 inhibitor in counteracting cognitive decline in different models of dementia targeting the AKT, JAK/STAT signaling pathways and hippocampal Klotho expression, to judge the neuroprotective, anti-apoptotic and anti-inflammatory effects of the drug. Cognitive decline was induced by either administration of high fat high sugar (HFHS) diet for 45 days alone, or with oral administration of AlCl₃ (100 mg/kg/day) for 60 days. Rats were orally administered Vildagliptin (10 mg/kg) for 60 days along with AlCl₃ administration. Vildagliptin treatment improved spatial memory and activities in morris water maze (MWM) test and open field test respectively. Results revealed an increase of both hippocampal klotho and Bcl-2 expressions along with an increase in both AKT and ERK1/2 phosphorylation. In contrast, Vildagliptin treatment decreased hippocampal contents of inflammatory, apoptotic and oxidative stress biomarkers as TNF-α, caspase-3 and FOXO1 along with restoring metabolic abnormalities. A significant decrease in BAX expressions with JAK2/STAT3 inhibition was observed. These findings demonstrate that the neuroprotective role of vildagliptin is possibly via modulating Klotho protein together with AKT pathway.

CCL18-NIR1 promotes oral cancer cell growth and metastasis by activating the JAK2/STAT3 signaling pathway

BACKGROUND

Chemokine (C-C motif) ligand 18 (CCL18) affects the malignant progression of varying cancers by activating chemokine receptors. Our previous work has shown that CCL18 promotes hyperplasia and invasiveness of oral cancer cells; however, the cognate receptors of CCL18 involved in the pathogenesis of oral squamous cell carcinoma (OSCC) have not yet been identified. This study aimed to investigate the molecular mechanisms which underlie promotive effects of CCL18 on OSCC progression by binding to functional receptors.

METHODS

The expression of CCL18 receptor-NIR1 in OSCC was determined by conducting western blot, immunofluorescence, and immunocytochemistry assays. Chi square test was applied to analyze the relationship between expression levels of NIR1 and clinicopathological variables. Recombinant CCL18 (rCCL18), receptor siRNA and JAK specific inhibitor (AG490) were used in experiments investigating the effects of the CCL18-NIR1 axis on growth of cancer cells (i.e., proliferation, and metastasis), epithelial-mesenchymal transition (EMT) and the activation of the JAK2/STAT3 signaling pathway.

RESULTS

NIR1 as functional receptor of CCL18 in OSCC, was found to be significantly upregulated in OSCC and positively related to the TNM stage of OSCC patients. rCCL18 induced the phenotypical alterations in oral cancer cells including cell growth, metastasis and EMT. The JAK2/STAT3 signaling pathway was confirmed to be a downstream pathway mediating the effects of CCL18 in OSCC. AG490 and knockdown of NIR1 could block the effects of rCCL18-induced OSCC.

CONCLUSION

CCL18 can promote the progression of OSCC by binding NIR1, and the CCL18-NIR1 axis can activate JAK2/STAT3 signaling pathway. The identification of the mechanisms underlying CCL18-mediated promotion of OSCC progression could highlight potential therapeutic targets for treating oral cancer.

An Integrated Transcriptomic and Proteomic Analysis Identifies Significant Novel Pathways for Henoch-Schönlein Purpura Nephritis Progression

Background

Although Henoch-Schönlein purpura nephritis (HSPN) is characterized by glomerular deposition of aberrantly glycosylated immunoglobulin A1 (IgA1), the underlying mechanism of HSPN progression has not yet been completely elucidated. In this study, we integrated transcriptomic and proteomic analyses to explore the underlying mechanism of HSPN progression.

Methods

RNA sequencing and tandem mass tag- (TMT-) based quantitative proteomics were used to gain serum transcriptomic and proteomic profiles of patients with different types of HSPN (3 × type 1, 3 × type 2, and 3 × type 3). Student's t-tests were performed to obtain the significance of the differential gene expression. The clusterProfiler package was used to conduct the functional annotation of the DEGs for both Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways.

Results

A total of 2315 mRNAs and 30 proteins were differentially expressed between the different types of HSPN. 58 mRNAs and one protein changed continuously during HSPN development and are potential biomarkers for HSPN progression. The validation cohort (another 9 patients) confirmed the high-throughput results of the transcriptomic and proteomic analyses. A total of 385 significant pathways were related to HSPN progression, and four of them were closely related to clinical biochemical indicators and may play an important role in the progression of HSPN. Those pathways reveal that HSPN progression may be related to the inhibition of inflammation, promotion of apoptosis, and repair of renal injury.

Conclusions

Four pathways were found to be closely related to HSPN progression, and it seems that HSPN progression is mainly due to the inhibition of inflammation, promotion of apoptosis, and repair of renal injury.

JAK-STAT Activity in Peripheral Blood Cells and Kidney Tissue in IgA Nephropathy

BACKGROUND AND OBJECTIVES

IgA nephropathy is the most common primary glomerular disease in the world. Marked by mesangial inflammation and proliferation, it generally leads to progressive kidney fibrosis. As the Janus kinase signal transducer and activator of transcription pathway has been implicated as an important mediator of diabetic kidney disease and FSGS, detailed investigation of this pathway in IgA nephropathy was undertaken to establish the basis for targeting this pathway across glomerular diseases.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Well characterized patients with IgA nephropathy and controls were studied, allowing us to compare 77 patients with biopsy-proven IgA nephropathy with 45 healthy subjects. STAT phosphorylation was assessed in peripheral blood monocytes (PBMCs) by phosphoflow before and after cytokine stimulation. Kidney Janus kinase signal transducer and activator of transcription activity was studied by immunofluorescence and by transcriptomic studies. An STAT1 activity score was established using downstream transcriptional targets of pSTAT1 and associated with disease and clinical outcomes.

RESULTS

We found PBMCs to have upregulated pSTAT production at baseline in patients with IgA nephropathy with a limited reserve to respond to cytokine stimulation compared with controls. Increased staining in glomerular mesangium and endothelium was seen for Jak-2 and pSTAT1 and in the tubulointerstitial for JAK2, pSTAT1, and pSTAT3. Activation of the Janus kinase signal transducer and activator of transcription pathway was further supported by increased pSTAT1 and pSTAT3 scores in glomerular and tubulointerstitial sections of the kidney (glomerular activation Z scores: 7.1 and 4.5, respectively; P values: <0.001 and <0.001, respectively). Clinically, phosphoflow results associated with proteinuria and kidney function, and STAT1 activation associated with proteinuria but was not associated with progression.

CONCLUSIONS

Janus kinase signal transducer and activator of transcription signaling was activated in patients with IgA nephropathy compared with controls. There were altered responses in peripheral immune cells and increased message and activated proteins in the kidney. These changes variably related to proteinuria and kidney function.

Inhibition of STAT3 in tubular epithelial cells prevents kidney fibrosis and nephropathy in STZ-induced diabetic mice

Recent evidences indicate that signal transducer and activator of transcription 3 (STAT3) is one of the crucial signaling pathways in the progression of diabetic nephropathy (DN). Here, we investigated the hypothesis that pharmacological blockade of STAT3 limits the progression of DN. Treatment with selective STAT3 inhibitor, S3I-201 for 16 weeks significantly attenuated kidney injuries in streptozotocin (STZ) induced diabetic mice, associated with downregulated expression of TGF-β1, ACE/AT1, and VEGF in diabetic mouse kidneys. Similar results were confirmed using genetic knockdown of STAT3 in mouse kidneys by injections of AAV2 expressing STAT3 shRNA in diabetic mouse. Further, STAT3 localization in kidney tissue was evaluated using immunofluorescent double-staining analysis, which indicated that STAT3 expression was mainly in the tubular epithelial cells. As expected, in renal tubular epithelial NRK-52E cells, high glucose (HG)-induced overexpression of TGF-β1, ACE/AT1, and VEGF were abrogated by S3I-201 pretreatment, as well as by genetic knockdown of STAT3 using specific siRNA sequence. This study found that renal tubular epithelial cells contributed to STAT3-mediated progression of DN and provided the first evidence that pharmacological inhibition of STAT3 attenuates DN.

JAK1/JAK2 inhibition by baricitinib in diabetic kidney disease: results from a Phase 2 randomized controlled clinical trial

Background

Inflammation signaled by Janus kinases (JAKs) promotes progression of diabetic kidney disease (DKD). Baricitinib is an oral, reversible, selective inhibitor of JAK1 and JAK2. This study tested the efficacy of baricitinib versus placebo on albuminuria in adults with Type 2 diabetes at high risk for progressive DKD.

Methods

In this Phase 2, double-blind, dose-ranging study, participants were randomized 1:1:1:1:1 to receive placebo or baricitinib (0.75 mg daily; 0.75 mg twice daily; 1.5 mg daily; or 4 mg daily), for 24 weeks followed by 4–8 weeks of washout.

Results

Participants (N = 129) were 63±9.1 (mean±standard deviation) years of age, 27.1% (35/129) women and 11.6% (15/129) African-American race. Baseline hemoglobin A1c (HbA1c) was 7.3±1% and estimated glomerular filtration rate was 45.0±12.1 mL/min/1.73 m² with first morning urine albumin–creatinine ratio (UACR) of 820 (407–1632) (median; interquartile range) mg/g. Baricitinib, 4 mg daily, decreased morning UACR by 41% at Week 24 compared with placebo (ratio to baseline 0.59, 95% confidence interval 0.38–0.93, P = 0.022). UACR was decreased at Weeks 12 and 24 and after 4–8 weeks of washout. Baricitinib 4 mg decreased inflammatory biomarkers over 24 weeks (urine C–X–C motif chemokine 10 and urine C–C motif ligand 2, plasma soluble tumor necrosis factor receptors 1 and 2, intercellular adhesion molecule 1 and serum amyloid A). The only adverse event rate that differed between groups was anemia at 32.0% (8/25) for baricitinib 4 mg daily versus 3.7% (1/27) for placebo.

Conclusions

Baricitinib decreased albuminuria in participants with Type 2 diabetes and DKD. Further research is required to determine if baricitinib reduces DKD progression.

Tissue-specific mouse mRNA isoform networks

Alternative Splicing produces multiple mRNA isoforms of genes which have important diverse roles such as regulation of gene expression, human heritable diseases, and response to environmental stresses. However, little has been done to assign functions at the mRNA isoform level. Functional networks, where the interactions are quantified by their probability of being involved in the same biological process are typically generated at the gene level. We use a diverse array of tissue-specific RNA-seq datasets and sequence information to train random forest models that predict the functional networks. Since there is no mRNA isoform-level gold standard, we use single isoform genes co-annotated to Gene Ontology biological process annotations, Kyoto Encyclopedia of Genes and Genomes pathways, BioCyc pathways and protein-protein interactions as functionally related (positive pair). To generate the non-functional pairs (negative pair), we use the Gene Ontology annotations tagged with "NOT" qualifier. We describe 17 Tissue-spEcific mrNa iSoform functIOnal Networks (TENSION) following a leave-one-tissue-out strategy in addition to an organism level reference functional network for mouse. We validate our predictions by comparing its performance with previous methods, randomized positive and negative class labels, updated Gene Ontology annotations, and by literature evidence. We demonstrate the ability of our networks to reveal tissue-specific functional differences of the isoforms of the same genes. All scripts and data from TENSION are available at: https://doi.org/10.25380/iastate.c.4275191 .

Effect of liraglutide on the Janus kinase/signal transducer and transcription activator (JAK/STAT) pathway in diabetic kidney disease in db/db mice and in cultured endothelial cells

BACKGROUND

Emerging evidence demonstrates the involvement of Janus tyrosine kinase/signal transducer and transcription activator (JAK/STAT) proteins in the pathophysiology of diabetic kidney disease (DKD). The JAK/STAT pathway is involved in the inflammatory response and endothelial cell dysfunction observed in DKD. The glucagon-like peptide-1 (GLP-1) analog liraglutide is an effective treatment for type 2 diabetes because it improves the inflammatory changes observed in experimental models of DKD. This study used db/db mice and endothelial cells (ECs) to determine the effect of diabetic environment on the JAK/STAT pathway and to assess the potential effect of liraglutide (200 μg/kg) in both models.

METHODS

Diabetic db/db mice (12 weeks old) were treated with liraglutide for 14 weeks. The kidneys were then perfused with saline and removed for mRNA, protein, and immunohistochemical analyses. Endothelial cells were stimulated advanced glycation end products (AGEs) (200 μg/μL) glucose (200 mg/dL) and liraglutide (100 nM) for 24 hours. Total RNA and protein were extracted and analyzed for expression of JAK/STAT signaling.

RESULTS

Phosphorylated (p-) STAT3 was significantly upregulated in db/db mice compared with non-diabetic mice. Liraglutide significantly downregulated p-STAT3 protein expression in db/db mice. In db/db mice, p-STAT3 was primarily expressed in the glomeruli, whereas p-JAK2 was also expressed in kidney tubules. In ECs, liraglutide treatment prevented increased expression of p-STAT3 and p-JAK2. Liraglutide inhibited the target gene suppressor of cytokine signaling 3 (SOCS3) and sirtuin 1 (SIRT1) in db/db mice and in cultured EC.

CONCLUSIONS

This study suggests that the GLP-1 analog liraglutide inhibits the JAK/STAT pathway, which participates in intracellular processes in experimental models of diabetes.

A preclinical overview of emerging therapeutic targets for glomerular diseases

Introduction: Animal models have provided significant insights into the mechanisms responsible for the development of glomerular lesions and proteinuria; they have also helped to identify molecules that control the podocyte function as suitable target-specific therapeutics. Areas covered: We discuss putative therapeutic targets for proteinuric glomerular diseases. An exhaustive search for eligible studies was performed in PubMed/MEDLINE. Most of the selected reports were published in the last decade, but we did not exclude older relevant milestone publications. We consider the molecules that regulate podocyte cytoskeletal dynamics and the transcription factors that regulate the expression of slit-diaphragm proteins. There is a focus on SGLT2 and sirtuins which have recently emerged as mediators of podocyte injury and repair. We also examine paracrine signallings involved in the cross-talk of injured podocytes with the neighbouring glomerular endothelial cells and parietal epithelial cells. Expert opinion: There is a need to discover novel therapeutic moleecules with renoprotective effects for those patients with glomerular diseases who do not respond completely to standard therapy. Emerging strategies targeting components of the podocyte cytoskeleton or signallings that regulate cellular communication within the glomerulus are promising avenues for treating glomerular diseases.

PTPN2 improved renal injury and fibrosis by suppressing STAT-induced inflammation in early diabetic nephropathy

Diabetic nephropathy (DN) is a chronic inflammatory disease triggered by disordered metabolism. Recent studies suggested that protein tyrosine phosphatase non‐receptor type 2 (PTPN2) could ameliorate metabolic disorders and suppress inflammatory responses. This study investigated PTPN2's role in modulating DN and the possible cellular mechanisms involved. In a mouse model combining hyperglycaemia and hypercholesterolaemia (streptozotocin diabetic, ApoE^‐/‐ mice), mice showed severe insulin resistance, renal dysfunction, micro‐inflammation, subsequent extracellular matrix expansion and decreased expression of PTPN2. We found that mice treated with PTPN2 displayed reduced serum creatinine, serum BUN and proteinuria. PTPN2 gene therapy markedly attenuated metabolic disorders and hyperglycaemia. In addition, PTPN2 gene transfer significantly suppressed renal activation of signal transducers and activators of transcription (STAT), STAT‐dependent pro‐inflammatory and pro‐fibrotic genes expression, and influx of lymphocytes in DN, indicating anti‐inflammatory effects of PTPN2 by inhibiting the activation of STAT signalling pathway in vivo. Furthermore, PTPN2 overexpression inhibited the high‐glucose induced phosphorylation of STAT, target genes expression and proliferation in mouse mesangial and tubuloepithelial cells, suggesting that the roles of PTPN2 on STAT activation was independent of glycaemic changes. Our results demonstrated that PTPN2 gene therapy could exert protective effects on DN via ameliorating metabolic disorders and inhibiting renal STAT‐dependent micro‐inflammation, suggesting its potential role for treatment of human DN.

Lipid Accumulation and Chronic Kidney Disease

Obesity and hyperlipidemia are the most prevalent independent risk factors of chronic kidney disease (CKD), suggesting that lipid accumulation in the renal parenchyma is detrimental to renal function. Non-esterified fatty acids (also known as free fatty acids, FFA) are especially harmful to the kidneys. A concerted, increased FFA uptake due to high fat diets, overexpression of fatty acid uptake systems such as the CD36 scavenger receptor and the fatty acid transport proteins, and a reduced β-oxidation rate underlie the intracellular lipid accumulation in non-adipose tissues. FFAs in excess can damage podocytes, proximal tubular epithelial cells and the tubulointerstitial tissue through various mechanisms, in particular by boosting the production of reactive oxygen species (ROS) and lipid peroxidation, promoting mitochondrial damage and tissue inflammation, which result in glomerular and tubular lesions. Not all lipids are bad for the kidneys: polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) seem to help lag the progression of chronic kidney disease (CKD). Lifestyle interventions, especially dietary adjustments, and lipid-lowering drugs can contribute to improve the clinical outcome of patients with CKD.

Macrophages: versatile players in renal inflammation and fibrosis

Macrophages have important roles in immune surveillance and in the maintenance of kidney homeostasis; their response to renal injury varies enormously depending on the nature and duration of the insult. Macrophages can adopt a variety of phenotypes: at one extreme, M1 pro-inflammatory cells contribute to infection clearance but can also promote renal injury; at the other extreme, M2 anti-inflammatory cells have a reparative phenotype and can contribute to the resolution phase of the response to injury. In addition, bone marrow monocytes can differentiate into myeloid-derived suppressor cells that can regulate T cell immunity in the kidney. However, macrophages can also promote renal fibrosis, a major driver of progression to end-stage renal disease, and the CD206⁺ subset of M2 macrophages is strongly associated with renal fibrosis in both human and experimental diseases. Myofibroblasts are important contributors to renal fibrosis and recent studies provide evidence that macrophages recruited from the bone marrow can transition directly into myofibroblasts within the injured kidney. This process is termed macrophage-to-myofibroblast transition (MMT) and is driven by transforming growth factor-β1 (TGFβ1)-Smad3 signalling via a Src-centric regulatory network. MMT may serve as a key checkpoint for the progression of chronic inflammation into pathogenic fibrosis.

Danzhi Jiangtang Capsule ameliorates kidney injury via inhibition of the JAK-STAT signaling pathway and increased antioxidant capacity in STZ-induced diabetic nephropathy rats

Danzhi Jiangtang Capsule (DJC), a traditional Chinese medicinal formula, has been used clinically in treating diabetes and diabetic nephropathy (DN). We previously demonstrated that DJC is capable of improving renal function in patients and rats with DN, but the mechanisms underlying these therapeutic benefits of DJC are not quite clear yet. In this study, STZ-induced diabetic rats were orally administered DJC for 8 weeks. Fasting blood glucose, renal function indicators in the serum, renal index, and the expression of proteins related to JAK-STAT signaling pathway were evaluated at the end of the experiment. The kidneys were sliced for pathological histology. Antioxidant status was assessed by measuring SOD, LPO and MDA in serum. The expression levels of COX2, iNOS, SOCS and the phosphorylation status of JAK2, STAT1, and STAT3 in renal tissues were evaluated by Western blot analyses. IL-6, TNF-α, and MCP-1 expression levels in renal tissues were determined using double-antibody sandwich ELISA. Diabetic renal dysfunction and its associated pathologies were ameliorated by DJC treatment. DJC significantly reversed the high expression of COX2 and iNOS in renal tissues. Furthermore, DJC inhibited the JAK2-STAT1/STAT3-SOCS3 signaling pathway, resulting in decreased concentrations of IL-6, TNF-α, and MCP-1. Moreover, the oxidant status in the kidney was substantially ameliorated by DJC treatment. In conclusion, the ability of DJC to ameliorate diabetic renal dysfunction and the associated pathologies of this disease might be due to its antioxidant capacity and suppression of the JAK2-STAT1/STAT3 cascade.

Transcriptomic analysis uncovers novel synergistic mechanisms in combination therapy for lupus nephritis

A recent clinical study showed that combination therapy consisting of mycophenolate mofetil, tacrolimus and steroids was shown to be more effective in achieving complete remission in patients with severe forms of lupus nephritis than conventional therapy consisting of intravenous cyclophosphamide and steroids. To explore the underlying molecular and cellular mechanisms of increased efficacy of the combination therapy regimen, we employed a mouse model of lupus nephritis, MRL/lpr mice, and treated them with monotherapies of prednisone, mycophenolate mofetil, or tacrolimus, or with their combination. Consistent with previous clinical findings, combination therapy markedly improved renal outcome compared to the monotherapies in mice with lupus nephritis. Transcriptomic analysis of their kidneys revealed distinct molecular pathways that were differentially regulated in combination therapy versus monotherapies. Combination therapy not only provided additive immunosuppressive effects, but also induced gene expression and molecular pathways to confer enhanced renoprotection. Specifically, combination therapy inhibited TLR7 expression in the kidneys of mice with lupus nephritis; combination of tacrolimus and mycophenolate mofetil led to better stabilization of the podocyte actin cytoskeleton through the reciprocal regulation of RhoA and Rac1 activities. Combination therapy strongly suppressed the IL-6/Stat3 pathway. These findings were further validated in renal biopsy samples from patients with lupus nephritis before and after treatments with mycophenolate mofetil, tacrolimus or combination therapy. Thus, our study further supports the earlier clinical finding and further provides insights into the molecular basis for increased efficacy of combination therapy.

Targeting inflammation in diabetic nephropathy: a tale of hope

INTRODUCTION

Diabetic nephropathy (DN) is the leading cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD). Beyond the new anti-diabetic drugs that possess markedly cardiovascular and renal protective effects, no novel direct therapies for DN have become available on the market in the last twenty years. Recently well-designed clinical trials for the treatment of DN, with attractive pathogenetic rationale, e.g. bardoxolone and atrasentan, were canceled or stopped because of safety concerns or lack of reaching the end points, respectively.

AREAS COVERED

In this review, we focus on the involvement of inflammation in the pathogenesis of DN. We update information from recent experimental and clinical studies that reported beneficial effects of several agents targeting chemokines, cytokines, transcription factors and kinases as well as several compounds with anti-inflammatory properties on DN.

EXPERT OPINION

Inflammation plays a key role in the DN progression. Preclinical studies have identified several anti-inflammatory molecules that effective decrease albuminuria and/or proteinuria. However, limited clinical trials in humans have been performed to confirm these results. Inhibitors of CCL2/CCR2, IL-1β and JAK/STAT pathways, and Nrf2 inducers are promising therapeutic options to improve the renal outcome of patients with DN, but appropriate clinical trials are necessary.

SOCS1-targeted therapy ameliorates renal and vascular oxidative stress in diabetes via STAT1 and PI3K inhibition

Oxidative stress resulting from excessive production of reactive oxygen species (ROS) or impaired antioxidant defenses is closely related to the development of diabetic vascular complications, including nephropathy and atherosclerosis. Chronic activation of Janus kinase/Signal transducer and activator of transcription (JAK/STAT) signaling pathway contributes to diabetic complications by inducing expression of genes involved in cell proliferation, fibrosis, inflammation, and oxidative stress. Suppressors of cytokine signaling (SOCS) family of endogenous JAK/STAT regulators is an attractive target for therapeutic intervention. We investigated the beneficial effect of two different SOCS1-targeted therapies (adenovirus-mediated gene transfer and kinase-inhibitory region peptidomimetic) to combat oxidative stress injury in an experimental diabetes model of concomitant renal and macrovascular disease (streptozotocin-induced diabetic apolipoprotein E-deficient mouse). Diabetes resulted in progressive alteration of redox balance in mice, as demonstrated by increased ROS levels and decreased antioxidant activity, which ultimately led to renal dysfunction and vascular injury. The molecular and pathological alterations in early diabetes were partially reversed by preventive intervention with SOCS1-targeted therapies. Importantly, SOCS1 peptidomimetic provided reno- and atheroprotection in diabetic mice even in a setting of established disease. Compared with untreated controls, kidney and aorta from SOCS1-treated mice exhibited significantly lower levels of superoxide anion, DNA oxidation marker and NADPH oxidase (Nox) subunits, along with higher expression of antioxidant enzymes. These trends correlated with a reduction in parameters of renal damage (albuminuria, creatinine and tubular injury), atherosclerosis (lesion size) and inflammation (leukocytes and chemokines). Mechanistic studies in renal, vascular and phagocytic cells exposed to cytokines and high-glucose showed that SOCS1 blocked ROS generation by inhibiting both Nox complex assembly and Nox subunit expression, an effect mediated by inactivation of JAK2, STAT1, and PI3K signaling pathways. This study provides evidence for SOCS1-targeted therapies, especially SOCS1 peptidomimetic, as an alternative antioxidant strategy to limit the progression of diabetic micro- and macrovascular complications.

JAK-STAT signaling is activated in the kidney and peripheral blood cells of patients with focal segmental glomerulosclerosis

Focal segmental glomerular sclerosis (FSGS) is a devastating disease with limited treatment options and poor prognosis. Activated JAK-STAT signaling has been implicated in other kidney diseases. Since new technologies allow us to better evaluate changes in systemic and renal JAK-STAT activity as it relates to kidney function, we examined this in 106 patients with biopsy-proven FSGS compared to 47 healthy control individuals. Peripheral immune function was assessed in peripheral blood mononuclear cells by phosphoflow studies before and after cytokine stimulation. Kidney JAK-STAT activity was measured by immunofluorescence and by transcriptomics. A STAT1 activity score was calculated by evaluating message status of downstream targets of pSTAT 1. Peripheral blood mononuclear cells were found to be upregulated in terms of pSTAT production at baseline in FSGS and to have limited reserve to respond to various cytokines. Increased staining for components of the JAK-STAT system in FSGS by microscopy was found. Furthermore, we found transcriptomic evidence for activation of JAK-STAT that increased pSTAT 1 and pSTAT 3 in glomerular and tubulointerstitial sections of the kidney. Some of these changes were associated with the likelihood of remission of proteinuria and progression of disease. JAK-STAT signaling is altered in patients with FSGS as compared to healthy controls with activated peripheral immune cells, increased message in the kidney and increased activated proteins in the kidney. Thus, our findings support immune activation in this disease and point to the JAK-STAT pathway as a potential target for treatment of FSGS.

In glomerular cells of puromycin aminonucleoside nephrosis rats both phosphorylated and total STAT3 levels increased during proteinuria

Recent studies showed that JAK/STAT pathway plays role in glomerular damages. The fact that STAT3 could be activated also by oxidative stress make Puromycin Aminonucleoside (PAN) Nephrosis model very appropriate for examination of STAT3 expression changes in glomerular pathology. Along with a control group, three PAN groups sacrificed on different days were formed by the i.p. injection of PAN for 5 consecutive days. Throughout the experiment, 24-hour-urines were collected on specific days and proteinuria levels were monitored. At the end of the experiments, tissue specimens were stained immunohistochemically for both total and phosphorylated STAT3 and evaluated subjectively. They were also examined ultrastructurally in transmission electron microscope. The proteinuria levels did not increase significantly on 5th day but showed a dramatic increase on 10th and 15th days. On 20th and 25th days, urinary protein levels gradually decreased. Ultrastructural examinations showed glomerular damages such as significant decrease in slit pore number, a significant gradual increase in glomerular basement membrane thickness and podocyte hypertrophy on 5th and 15th days; besides significant increase in mesangial matrix. The first significant increases in phosphorylated and total STAT3 levels occurred in 5th day and 15th day groups respectively. These increases diminished in 25th day group. Regarding all the findings, it was deduced that STAT3 is one of the active factors in glomerular pathologies.