Effects of Selonsertib in Patients with Diabetic Kidney Disease

Apoptosis signal-regulating kinase 1 promotes inflammation in senescence and aging

Cellular senescence is a stress-induced, permanent cell cycle arrest involved in tumor suppression and aging. Senescent cells secrete bioactive molecules such as pro-inflammatory cytokines and chemokines. This senescence-associated secretory phenotype (SASP) has been implicated in immune-mediated elimination of senescent cells and age-associated chronic inflammation. However, the mechanisms regulating the SASP are incompletely understood. Here, we show that the stress-responsive kinase apoptosis signal-regulating kinase 1 (ASK1) promotes inflammation in senescence and aging. ASK1 is activated during senescence and increases the expression of pro-inflammatory cytokines and chemokines by activating p38, a kinase critical for the SASP. ASK1-deficient mice show impaired elimination of oncogene-induced senescent cells and an increased rate of tumorigenesis. Furthermore, ASK1 deficiency prevents age-associated p38 activation and inflammation and attenuates glomerulosclerosis. Our results suggest that ASK1 is a driver of the SASP and age-associated chronic inflammation and represents a potential therapeutic target for age-related diseases.

The currrent landscape of antifibrotic therapy across different organs: A systematic approach

Fibrosis is a common pathological process that can affect virtually all the organs, but there are hardly any effective therapeutic options. This has led to an intense search for antifibrotic therapies over the last decades, with a great number of clinical assays currently underway. We have systematically reviewed all current and recently finished clinical trials involved in the development of new antifibrotic drugs, and the preclinical studies analyzing the relevance of each of these pharmacological strategies in fibrotic processes affecting tissues beyond those being clinically studied. We analyze and discuss this information with the aim of determining the most promising options and the feasibility of extending their therapeutic value as antifibrotic agents to other fibrotic conditions.

Discovery of benzoheterocyclic-substituted amide derivatives as apoptosis signal-regulating kinase 1 (ASK1) inhibitors

Three series of benzoheterocyclic-substituted amide derivatives were designed and synthesized as potent ASK1 inhibitors in this work. After undergoing continuous structural optimization, compound 17a was discovered to be a novel inhibitor of ASK1 with good potency (kinase, IC50 = 26 nM), noteworthy liver microsomal stability (human, T1/2 = 340.4 min), good pharmacokinetic parameters (rat, T1/2 p.o. = 2.11 h, AUClast p.o. = 10 900 h ng mL-1) and high oral bioavailability (rat, F = 97.9%), while also being inactive towards hERG (IC50 > 10 μM).

Intervention treatment reducing cellular senescence inhibits tubulointerstitial fibrosis in diabetic mice following acute kidney injury

Senescence of kidney tubules leads to tubulointerstitial fibrosis (TIF). Proximal tubular epithelial cells undergo stress-induced senescence during diabetes and episodes of acute kidney injury (AKI), and combining these injuries promotes the progression of diabetic kidney disease (DKD). Since TIF is crucial to progression of DKD, we examined the therapeutic potential of targeting senescence with a senolytic drug (HSP90 inhibitor) and/or a senostatic drug (ASK1 inhibitor) in a model of TIF in which AKI is superimposed on diabetes. After 8 weeks of streptozotocin-induced diabetes, mice underwent bilateral clamping of renal pedicles to induce mild AKI, followed by 28 days of reperfusion. Groups of mice (n=10-12) received either vehicle, HSP90 inhibitor (alvespimycin), ASK1 inhibitor (GS-444217), or both treatments. Vehicle-treated mice displayed tubular injury at day 3 and extensive tubular cell senescence at day 10, which remained unresolved at day 28. Markers of senescence (Cdkn1a and Cdkn2a), inflammation (Cd68, Tnf, and Ccl2), and TIF (Col1a1, Col4a3, α-Sma/Acta2, and Tgfb1) were elevated at day 28, coinciding with renal function impairment. Treatment with alvespimycin alone reduced kidney senescence and levels of Col1a1, Acta2, Tgfb1, and Cd68; however, further treatment with GS-444217 also reduced Col4a3, Tnf, Ccl2, and renal function impairment. Senolytic therapy can inhibit TIF during DKD, but its effectiveness can be improved by follow-up treatment with a senostatic inhibitor, which has important implications for treating progressive DKD.

Discovery of a quinoline-containing compound JT21-25 as a potent and selective inhibitor of apoptosis signal-regulating kinase 1 (ASK1)

ASK1 kinase inhibition has become a promising strategy for treating inflammatory diseases, such as non-alcoholic steatohepatitis and multiple sclerosis. Here, we reported the discovery of a promising compound 9h (JT21-25) containing quinoline structures as a potent small molecule inhibitor of ASK1. The compound JT21-25 was selective against MAP3K kinases TAK1 (>1960.8-fold), and much higher than the selectivity of GS-4997 for TAK1 (312.3-fold). In addition, different concentrations of JT21-25 did not show significant toxicity in normal LO2 liver cells, and the cell survival rate was greater than 80 %. The Oil Red O staining experiment showed that at the 4 μM and 8 μM concentrations of JT21-25, only slight cytoplasmic fat droplets were observed in LO2 cells, and there was no significant fusion between fat droplets. In the biochemical analysis experiment, JT21-25 significantly reduced the content of CHOL, LDL, TG, ALT, and AST. In summary, these findings suggested that compound JT21-25 might be valuable for further investigation as a potential candidate in the treatment of associated diseases.

Oxidative stress and the role of redox signalling in chronic kidney disease

Chronic kidney disease (CKD) is a major public health concern, underscoring a need to identify pathogenic mechanisms and potential therapeutic targets. Reactive oxygen species (ROS) are derivatives of oxygen molecules that are generated during aerobic metabolism and are involved in a variety of cellular functions that are governed by redox conditions. Low levels of ROS are required for diverse processes, including intracellular signal transduction, metabolism, immune and hypoxic responses, and transcriptional regulation. However, excess ROS can be pathological, and contribute to the development and progression of chronic diseases. Despite evidence linking elevated levels of ROS to CKD development and progression, the use of low-molecular-weight antioxidants to remove ROS has not been successful in preventing or slowing disease progression. More recent advances have enabled evaluation of the molecular interactions between specific ROS and their targets in redox signalling pathways. Such studies may pave the way for the development of sophisticated treatments that allow the selective control of specific ROS-mediated signalling pathways.

Novel pharmacological interventions for diabetic kidney disease

PURPOSE OF REVIEW

The purpose of this review is to summarize the latest evidence on the prevention and progression of diabetic kidney disease (DKD), as well as novel pharmacological interventions from preclinical and early clinical studies with promising findings in the reduction of this condition's burden.

RECENT FINDINGS

We will cover the latest evidence on the reduction of proteinuria and kidney function decline in DKD achieved through established renin-angiotensin-aldosterone system (RAAS) system blockade and the more recent addition of SGLT2i, nonsteroidal mineralocorticoid receptor antagonists (MRAs) and GLP1-RA, that combined will most likely integrate the mainstay for current DKD treatment. We also highlight evidence from new mechanisms of action in DKD, including other haemodynamic anti-inflammatory and antifibrotic interventions, oxidative stress modulators and cell identity and epigenetic targets.

SUMMARY

Renal specific outcome trials have become more popular and are increasing the available armamentarium to diminish the progression of renal decline in patients at greater risk of end-stage kidney disease (ESKD) such as diabetic individuals. A combined pharmaceutical approach based on available rigorous studies should include RAAS blockade, SGLT2 inhibitors, nonsteroidal MRA and expectedly GLP1-RA on a personalized based-intervention. New specific trials designed to address renal outcomes will be needed for innovative therapies to conclude on their potential benefits in DKD.

Novel Approaches in Chronic Renal Failure without Renal Replacement Therapy: A Review

Chronic kidney disease (CKD) is characterized by renal parenchymal damage leading to a reduction in the glomerular filtration rate. The inflammatory response plays a pivotal role in the tissue damage contributing to renal failure. Current therapeutic options encompass dietary control, mineral salt regulation, and management of blood pressure, blood glucose, and fatty acid levels. However, they do not effectively halt the progression of renal damage. This review critically examines novel therapeutic avenues aimed at ameliorating inflammation, mitigating extracellular matrix accumulation, and fostering renal tissue regeneration in the context of CKD. Understanding the mechanisms sustaining a proinflammatory and profibrotic state may offer the potential for targeted pharmacological interventions. This, in turn, could pave the way for combination therapies capable of reversing renal damage in CKD. The non-replacement phase of CKD currently faces a dearth of efficacious therapeutic options. Future directions encompass exploring vaptans as diuretics to inhibit water absorption, investigating antifibrotic agents, antioxidants, and exploring regenerative treatment modalities, such as stem cell therapy and novel probiotics. Moreover, this review identifies pharmaceutical agents capable of mitigating renal parenchymal damage attributed to CKD, targeting molecular-level signaling pathways (TGF-β, Smad, and Nrf2) that predominate in the inflammatory processes of renal fibrogenic cells.

Cellular crosstalk of mesangial cells and tubular epithelial cells in diabetic kidney disease

Diabetic kidney disease (DKD) is a major cause of end-stage renal disease and imposes a heavy global economic burden; however, little is known about its complicated pathophysiology. Investigating the cellular crosstalk involved in DKD is a promising avenue for gaining a better understanding of its pathogenesis. Nonetheless, the cellular crosstalk of podocytes and endothelial cells in DKD is better understood than that of mesangial cells (MCs) and renal tubular epithelial cells (TECs). As the significance of MCs and TECs in DKD pathophysiology has recently become more apparent, we reviewed the existing literature on the cellular crosstalk of MCs and TECs in the context of DKD to acquire a comprehensive understanding of their cellular communication. Insights into the complicated mechanisms underlying the pathophysiology of DKD would improve its early detection, care, and prognosis. Video Abstract.

Role of Semaphorin 3A in Kidney Development and Diseases

Kidney diseases are worldwide public health problems affecting millions of people. However, there are still limited therapeutic options against kidney diseases. Semaphorin 3A (SEMA3A) is a secreted and membrane-associated protein, which regulates diverse functions, including immune regulation, cell survival, migration and angiogenesis, thus involving in the several pathogeneses of diseases, including eyes and neurons, as well as kidneys. SEMA3A is expressed in podocytes and tubular cells in the normal adult kidney, and recent evidence has revealed that excess SEMA3A expression and the subsequent signaling pathway aggravate kidney injury in a variety of kidney diseases, including nephrotic syndrome, diabetic nephropathy, acute kidney injury, and chronic kidney disease. In addition, several reports have demonstrated that the inhibition of SEMA3A ameliorated kidney injury via a reduction in cell apoptosis, fibrosis and inflammation; thus, SEMA3A may be a potential therapeutic target for kidney diseases. In this review article, we summarized the current knowledge regarding the role of SEMA3A in kidney pathophysiology and their potential use in kidney diseases.

Tubular injury in diabetic kidney disease: molecular mechanisms and potential therapeutic perspectives

Diabetic kidney disease (DKD) is a chronic complication of diabetes and the leading cause of end-stage renal disease (ESRD) worldwide. Currently, there are limited therapeutic drugs available for DKD. While previous research has primarily focused on glomerular injury, recent studies have increasingly emphasized the role of renal tubular injury in the pathogenesis of DKD. Various factors, including hyperglycemia, lipid accumulation, oxidative stress, hypoxia, RAAS, ER stress, inflammation, EMT and programmed cell death, have been shown to induce renal tubular injury and contribute to the progression of DKD. Additionally, traditional hypoglycemic drugs, anti-inflammation therapies, anti-senescence therapies, mineralocorticoid receptor antagonists, and stem cell therapies have demonstrated their potential to alleviate renal tubular injury in DKD. This review will provide insights into the latest research on the mechanisms and treatments of renal tubular injury in DKD.

Targeting protein modifications in metabolic diseases: molecular mechanisms and targeted therapies

The ever-increasing prevalence of noncommunicable diseases (NCDs) represents a major public health burden worldwide. The most common form of NCD is metabolic diseases, which affect people of all ages and usually manifest their pathobiology through life-threatening cardiovascular complications. A comprehensive understanding of the pathobiology of metabolic diseases will generate novel targets for improved therapies across the common metabolic spectrum. Protein posttranslational modification (PTM) is an important term that refers to biochemical modification of specific amino acid residues in target proteins, which immensely increases the functional diversity of the proteome. The range of PTMs includes phosphorylation, acetylation, methylation, ubiquitination, SUMOylation, neddylation, glycosylation, palmitoylation, myristoylation, prenylation, cholesterylation, glutathionylation, S-nitrosylation, sulfhydration, citrullination, ADP ribosylation, and several novel PTMs. Here, we offer a comprehensive review of PTMs and their roles in common metabolic diseases and pathological consequences, including diabetes, obesity, fatty liver diseases, hyperlipidemia, and atherosclerosis. Building upon this framework, we afford a through description of proteins and pathways involved in metabolic diseases by focusing on PTM-based protein modifications, showcase the pharmaceutical intervention of PTMs in preclinical studies and clinical trials, and offer future perspectives. Fundamental research defining the mechanisms whereby PTMs of proteins regulate metabolic diseases will open new avenues for therapeutic intervention.

Precision Medicine and/or Biomarker Based Therapy in T2DM: Ready for Prime Time?

Approximately 30-40% of people with type 2 diabetes mellitus develop chronic kidney disease. This is characterised by elevated blood pressure, declining kidney function and enhanced cardiovascular morbidity and mortality. Increased albuminuria and decreasing estimated glomerular function has to be evaluated regularly to diagsnose kidney disease. New biomarkers may facilitate early diagnosis and provide infomation on undlying pathology thereby supporting early precision intervention for the optimal benefit. A number of biomarkers have been suggested but are not yet implemented in clinical practice. iI the future such bimarkers may pave the way for personalized treatment.

Clinical trials with reno-vascular end points in patients with diabetes: Changing the scenario over the past 20 years

Major clinical advances over the last 20 years in the area of diabetic kidney disease (DKD) have been confirmed in large seminal clinical trials. These findings add to the previously identified benefits resulting from intensive glucose and blood pressure control therapies. Furthermore, newer glucose lowering treatments such as SGLT2 inhibitors and GLP-1 agonists appear very promising and are likely to transform the management and outlook of DKD over the next decade. In addition, novel mineralocorticoid receptor antagonists and a recently reported trial with an endothelin receptor blocker also have the potential to change clinical practice.

Diabetic Kidney Care Redefined with a New Way into Remission

Diabetic kidney disease has been a leading cause for end-stage kidney disease. Traditional methods to slow progression include tight glycemic control, blood pressure control, and use of renin-angiotensin axis inhibitors. Finerenone and sodium glucose co-transporters have shown proven benefit in diabetic kidney disease regression recently. Other potential targets for slowing the decline in diabetic kidney disease are transforming growth factor beta, endothelin antagonist, protein kinase C inhibitors, advanced glycation end product inhibition, Janus kinase-signal transducer and activator of transcription pathway inhibition, phosphodiesterase 3 or 5 inhibitors, and Rho kinase inhibitor. These targets are at various trial phases and so far, show promising results.

Referral pattern to nephrologist and prognosis in diabetic kidney disease patients: Single center retrospective cohort study

BACKGROUND

Management of diabetic kidney disease (DKD) to prevent end-stage kidney disease (ESKD) has become a major challenge for health care professionals. This study aims to investigate the characteristics of patients with DKD when they are first referred to a nephrologist and the subsequent prognoses.

METHODS

A total of 307 patients who were referred to our department from October 2010 to September 2014 at Osaka General Medical Center were analyzed. Independent risk factors associated with renal replacement therapy (RRT) and cardiovascular composite events (CVE) following their nephrology referral were later identified using Cox proportional hazards analysis.

RESULTS

Of 307 patients, 26 (8.5%), 67 (21.8%), 134 (43.6%), and 80 (26.1%) patients were categorized as having chronic kidney disease (CKD) stages 3a, 3b, 4, and 5, respectively. The median estimated glomerular filtration rate (eGFR) and urinary protein levels were 22.3 mL/min/1.73 m2 and 2.83 g/gCr, respectively, at the time of the nephrology referral. During the follow-up period (median, 30 months), 121 patients required RRT, and more than half of the patients with CKD stages 5 and 4 reached ESKD within 60 months following their nephrology referral; 30% and <10% of the patients with CKD stages 3b and 3a, respectively, required RRT within 60 months following their nephrology referral.

CONCLUSION

Patients with DKD were referred to nephrologist at CKD stage 4. Although almost half of the patients with CKD stage 5 at the time of nephrology referral required RRT within one-and-a-half years after the referral, kidney function of patients who were referred to nephrologist at CKD stage 3 and 4 were well preserved.

Targeting inflammation to treat diabetic kidney disease: the road to 2030

Diabetic kidney disease (DKD) is one of the fastest growing causes of chronic kidney disease and associated morbidity and mortality. Preclinical research has demonstrated the involvement of inflammation in its pathogenesis and in the progression of kidney damage, supporting clinical trials designed to explore anti-inflammatory strategies. However, the recent success of sodium-glucose cotransporter-2 inhibitors and the nonsteroidal mineralocorticoid receptor antagonist finerenone has changed both guidelines and standard of care, rendering obsolete older studies directly targeting inflammatory mediators and the clinical development was discontinued for most anti-inflammatory drugs undergoing clinical trials for DKD in 2016. Given the contribution of inflammation to the pathogenesis of DKD, we review the impact on kidney inflammation of the current standard of care, therapies undergoing clinical trials, or repositioned drugs for DKD. Moreover, we review recent advances in the molecular regulation of inflammation in DKD and discuss potential novel therapeutic strategies with clinical relevance. Finally, we provide a road map for future research aimed at integrating the growing knowledge on inflammation and DKD into clinical practice to foster improvement of patient outcomes.

What's New in the Molecular Mechanisms of Diabetic Kidney Disease: Recent Advances

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease, including end-stage kidney disease, and increases the risk of cardiovascular mortality. Although the treatment options for DKD, including angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, sodium-glucose cotransporter 2 inhibitors, and mineralocorticoid receptor antagonists, have advanced, their efficacy is still limited. Thus, a deeper understanding of the molecular mechanisms of DKD onset and progression is necessary for the development of new and innovative treatments for DKD. The complex pathogenesis of DKD includes various different pathways, and the mechanisms of DKD can be broadly classified into inflammatory, fibrotic, metabolic, and hemodynamic factors. Here, we summarize the recent findings in basic research, focusing on each factor and recent advances in the treatment of DKD. Collective evidence from basic and clinical research studies is helpful for understanding the definitive mechanisms of DKD and their regulatory systems. Further comprehensive exploration is warranted to advance our knowledge of the pathogenesis of DKD and establish novel treatments and preventive strategies.

Emerging drugs for the treatment of diabetic nephropathy

INTRODUCTION

Diabetic nephropathy remains a significant economic and social burden on both the individual patient and health-care systems as the prevalence of diabetes increases in the general population. The complex pathophysiology of diabetic kidney disease poses a challenge in the development of effective medical treatments for the disease. However, the multiple facets of diabetic nephropathy also offer a variety of potential strategies to manage this condition.

AREAS COVERED

We retrieved PubMed, Cochrane Library, Scopus, Google Scholar, and ClinicalTrials.gov records to identify studies and articles focused on new pharmacologic advances to treat diabetic nephropathy.

EXPERT OPINION

RAAS blockers have remained the mainstay of therapy for DM nephropathy for many years, with only recent advancements with SGLT2 inhibitors and nonsteroidal MRAs. Better understanding of the long-term renal effects of ambient hyperglycemia, ranging from hemodynamic changes to increased production of oxidative and pro-inflammatory substances, has evolved our approach to the treatment of diabetic nephropathy. With continuing research for new therapeutics as well as combination therapy, the medical community may be able to better ease the burden of diabetic kidney disease.

Renal fibrosis as a hallmark of diabetic kidney disease: Potential role of targeting transforming growth factor-beta (TGF-β) and related molecules

INTRODUCTION

Diabetic kidney disease (DKD) is the most common cause of end-stage renal disease (ESRD) worldwide. Currently, there is no effective treatment to completely prevent DKD progression to ESRD. Renal fibrosis and inflammation are the major pathological features of DKD, being pursued as potential therapeutic targets for DKD.

AREAS COVERED

Inflammation and renal fibrosis are involved in the pathogenesis of DKD. Anti-inflammatory drugs have been developed to combat DKD but without efficacy demonstrated. Thus, we have focused on the mechanisms of TGF-β-induced renal fibrosis in DKD, as well as discussing the important molecules influencing the TGF-β signaling pathway and their potential development into new pharmacotherapies, rather than targeting the ligand TGF-β and/or its receptors, such options include Smads, microRNAs, histone deacetylases, connective tissue growth factor, bone morphogenetic protein 7, hepatocyte growth factor, and cell division autoantigen 1.

EXPERT OPINION

TGF-β is a critical driver of renal fibrosis in DKD. Molecules that modulate TGF-β signaling rather than TGF-β itself are potentially superior targets to safely combat DKD. A comprehensive elucidation of the pathogenesis of DKD is important, which requires a better model system and access to clinical samples via collaboration between basic and clinical researchers.

Recent Advances in the Emerging Therapeutic Strategies for Diabetic Kidney Diseases

Diabetic kidney disease (DKD) is one of the most common causes of end-stage renal disease worldwide. The treatment of DKD is strongly associated with clinical outcomes in patients with diabetes mellitus. Traditional therapeutic strategies focus on the control of major risk factors, such as blood glucose, blood lipids, and blood pressure. Renin–angiotensin–aldosterone system inhibitors have been the main therapeutic measures in the past, but the emergence of sodium–glucose cotransporter 2 inhibitors, incretin mimetics, and endothelin-1 receptor antagonists has provided more options for the management of DKD. Simultaneously, with advances in research on the pathogenesis of DKD, some new therapies targeting renal inflammation, fibrosis, and oxidative stress have gradually entered clinical application. In addition, some recently discovered therapeutic targets and signaling pathways, mainly in preclinical and early clinical trial stages, are expected to provide benefits for patients with DKD in the future. This review summarizes the traditional treatments and emerging management options for DKD, demonstrating recent advances in the therapeutic strategies for DKD.

Blocking CHOP-dependent TXNIP shuttling to mitochondria attenuates albuminuria and mitigates kidney injury in nephrotic syndrome

Albuminuria is a hallmark of glomerular disease of various etiologies. It is not only a symptom of glomerular disease but also a cause leading to glomerulosclerosis, interstitial fibrosis, and eventually, a decline in kidney function. The molecular mechanism underlying albuminuria-induced kidney injury remains poorly defined. In our genetic model of nephrotic syndrome (NS), we have identified CHOP (C/EBP homologous protein)-TXNIP (thioredoxin-interacting protein) as critical molecular linkers between albuminuria-induced ER dysfunction and mitochondria dyshomeostasis. TXNIP is a ubiquitously expressed redox protein that binds to and inhibits antioxidant enzyme, cytosolic thioredoxin 1 (Trx1), and mitochondrial Trx2. However, very little is known about the regulation and function of TXNIP in NS. By utilizing Chop-/- and Txnip-/- mice as well as 68Ga-Galuminox, our molecular imaging probe for detection of mitochondrial reactive oxygen species (ROS) in vivo, we demonstrate that CHOP up-regulation induced by albuminuria drives TXNIP shuttling from nucleus to mitochondria, where it is required for the induction of mitochondrial ROS. The increased ROS accumulation in mitochondria oxidizes Trx2, thus liberating TXNIP to associate with mitochondrial nod-like receptor protein 3 (NLRP3) to activate inflammasome, as well as releasing mitochondrial apoptosis signal-regulating kinase 1 (ASK1) to induce mitochondria-dependent apoptosis. Importantly, inhibition of TXNIP translocation and mitochondrial ROS overproduction by CHOP deletion suppresses NLRP3 inflammasome activation and p-ASK1-dependent mitochondria apoptosis in NS. Thus, targeting TXNIP represents a promising therapeutic strategy for the treatment of NS.

Selonsertib Enhances Kidney Protection Beyond Standard of Care in a Hypertensive, Secondary Glomerulosclerosis CKD Model

Background

Despite widespread use of renin-aldosterone-angiotensin system inhibitors and the benefits of lowering glomerular pressure in patients with CKD, there remains a major unmet need for therapies targeting underlying causes of CKD progression. Apoptosis signal-regulating kinase 1 (ASK1) promotes apoptosis and glomerulosclerosis, and is implicated in the progression of diabetic kidney disease (DKD), a major cause of CKD. Selonsertib is a selective ASK1 inhibitor currently in clinical development for the treatment of DKD. We examined the added benefits of selonsertib on existing glomerulosclerosis and related molecular pathways in the nondiabetic 5/6 nephrectomy (5/6 Nx) rat model in combination with the angiotensin-converting enzyme inhibitor (ACEI) enalapril.

Methods

Male Sprague Dawley rats underwent 5/6 Nx with kidney biopsy 8 weeks later for assessment of glomerulosclerosis, and were randomized to four treatment groups with equal glomerulosclerosis: selonsertib, enalapril, combination (selonsertib plus enalapril), and untreated controls. Serum creatinine, systolic BP (SBP), and urinary albumin were measured at intervals. Animals were euthanized at week 12 for histologic, biochemical, and molecular analyses.

Results

All rats developed hypertension, albuminuria, and glomerulosclerosis by week 8. Kidney function further declined, and glomerulosclerosis and albuminuria progressively increased in controls from week 8 to 12. Enalapril treatment alone from week 8 to 12 reduced SBP versus controls, decreased albuminuria, and resulted in numerically lower glomerulosclerosis. Selonsertib alone had no effect on SBP but preserved kidney function. Combined treatment significantly reduced glomerulosclerosis, with more regression than either monotherapy. Enalapril treatment resulted in fewer interstitial macrophages, whereas selonsertib treatment reduced apoptosis and podocyte loss. RNA-seq revealed that combined treatment influenced pathways related to extracellular matrix and wound healing.

Conclusions

Selonsertib targets a novel, nonhemodynamic pathway in CKD. Our data suggest that ASK1 inhibition, when combined with ACEI, has additive effects to reduce progression of glomerulosclerosis, attenuate kidney function decline, and reduce podocyte loss.

IL-17A in diabetic kidney disease: protection or damage

The effect of IL-17A in diabetic kidney disease (DKD) has received increasing attention. Interleukin (IL)-17A promotes renal inflammation and the progression of DKD, and IL-17A deficiency improves experimental DKD. However, recent studies have found that the effect of IL-17A on DKD is more complicated than the negative impact. IL-17A alleviates renal inflammation and fibrosis via regulating autophagy or the macrophage phenotype. Moreover, paradoxical expression of IL-17A has been reported in human DKD. This review focuses on how IL-17A affects the progression of DKD and the resulting opportunities and challenges.

Targeting inflammation for the treatment of Diabetic Kidney Disease: a five-compartment mechanistic model

Diabetic kidney disease (DKD) is the leading cause of kidney failure worldwide. Mortality and morbidity associated with DKD are increasing with the global prevalence of type 2 diabetes. Chronic, sub-clinical, non-resolving inflammation contributes to the pathophysiology of renal and cardiovascular disease associated with diabetes. Inflammatory biomarkers correlate with poor renal outcomes and mortality in patients with DKD. Targeting chronic inflammation may therefore offer a route to novel therapeutics for DKD. However, the DKD patient population is highly heterogeneous, with varying etiology, presentation and disease progression. This heterogeneity is a challenge for clinical trials of novel anti-inflammatory therapies. Here, we present a conceptual model of how chronic inflammation affects kidney function in five compartments: immune cell recruitment and activation; filtration; resorption and secretion; extracellular matrix regulation; and perfusion. We believe that the rigorous alignment of pathophysiological insights, appropriate animal models and pathology-specific biomarkers may facilitate a mechanism-based shift from recruiting ‘all comers’ with DKD to stratification of patients based on the principal compartments of inflammatory disease activity.

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.

Molecular Mechanisms and Therapeutic Targets for Diabetic Kidney Disease

Diabetic kidney disease has a high global disease burden and substantially increases risk of kidney failure and cardiovascular events. Despite treatment, there is substantial residual risk of disease progression with existing therapies. Therefore, there is an urgent need to better understand the molecular mechanisms driving diabetic kidney disease to help identify new therapies that slow progression and reduce associated risks. Diabetic kidney disease is initiated by diabetes-related disturbances in glucose metabolism, which then trigger other metabolic, hemodynamic, inflammatory, and fibrotic processes that contribute to disease progression. This review summarizes existing evidence on the molecular drivers of diabetic kidney disease onset and progression, focusing on inflammatory and fibrotic mediators-factors that are largely unaddressed as primary treatment targets and for which there is increasing evidence supporting key roles in the pathophysiology of diabetic kidney disease. Results from recent clinical trials highlight promising new drug therapies, as well as a role for dietary strategies, in treating diabetic kidney disease.

Advances in Immunosuppressive Agents Based on Signal Pathway

Immune abnormality involves in various diseases, such as infection, allergic diseases, autoimmune diseases, as well as transplantation. Several signal pathways have been demonstrated to play a central role in the immune response, including JAK/STAT, NF-κB, PI3K/AKT-mTOR, MAPK, and Keap1/Nrf2/ARE pathway, in which multiple targets have been used to develop immunosuppressive agents. In recent years, varieties of immunosuppressive agents have been approved for clinical use, such as the JAK inhibitor tofacitinib and the mTOR inhibitor everolimus, which have shown good therapeutic effects. Additionally, many immunosuppressive agents are still in clinical trials or preclinical studies. In this review, we classified the immunosuppressive agents according to the immunopharmacological mechanisms, and summarized the phase of immunosuppressive agents.

Recent advances in the pharmacotherapeutic management of diabetic kidney disease

INTRODUCTION

Diabetic kidney disease (DKD) remains a major cause of morbidity and mortality in diabetes and is a key cause of end-stage kidney disease (ESKD) worldwide. Major clinical advances have been confirmed in large trials demonstrating renoprotection, adding to the benefits of existing intensive glucose and blood pressure control therapies. Furthermore, there are exciting new treatments predominantly at an experimental and early clinical phase which appear promising.

AREAS COVERED

The authors review DKD in the context of existing and emerging therapies affording cardiorenal benefits including SGLT2 inhibitors and GLP-1 receptor agonists. They explore novel therapies demonstrating potential including a newly developed mineralocorticoid receptor antagonist and endothelin receptor blockade, while evaluating the utility of DPP4 inhibitors in current clinical practice. They also consider the recent evidence of emerging therapies targeting metabolic pathways with enzyme inhibitors, anti-fibrotic agents, and agents modulating transcription factors.

EXPERT OPINION

Significant improvements have been made in the management of DKD with SGLT2i and GLP-1 agonists providing impressive renoprotection, with novel progress in renin-angiotensin-aldosterone system (RAAS) blockade with finerenone. There is also great potential for several new experimental therapies. These advances provide us with optimism that the outlook of this devastating condition will continue to improve.

Urinary Thioredoxin as a Biomarker of Renal Redox Dysregulation and a Companion Diagnostic to Identify Responders to Redox-Modulating Therapeutics

Significance: The development and progression of renal diseases, including acute kidney injury (AKI) and chronic kidney disease (CKD), are the result of heterogeneous pathophysiology that reflects a range of environmental factors and, in a lesser extent, genetic mutations. The pathophysiology specific to most kidney diseases is not currently identified; therefore, these diseases are diagnosed based on non-pathological factors. For that reason, pathophysiology-based companion diagnostics for selection of pathophysiology-targeted treatments have not been available, which impedes personalized medicine in kidney disease. Recent Advances: Pathophysiology-targeted therapeutic agents are now being developed for the treatment of redox dysregulation. Redox modulation therapeutics, including bardoxolone methyl, suppresses the onset and progression of AKI and CKD. On the other hand, pathophysiology-targeted diagnostics for renal redox dysregulation are also being developed. Urinary thioredoxin (TXN) is a biomarker that can be used to diagnose tubular redox dysregulation. AKI causes oxidation and urinary excretion of TXN, which depletes TXN from the tubules, resulting in tubular redox dysregulation. Urinary TXN is selectively elevated at the onset of AKI and correlates with the progression of CKD in diabetic nephropathy. Critical Issues: Diagnostic methods should provide information about molecular mechanisms that aid in the selection of appropriate therapies to improve the prognosis of kidney disease. Future Directions: A specific diagnostic method enabling detection of redox dysregulation based on pathological molecular mechanisms is much needed and could provide the first step toward personalized medicine in kidney disease. Urinary TXN is a candidate for a companion diagnostic method to identify responders to redox-modulating therapeutics. Antioxid. Redox Signal. 36, 1051-1065.

Exploring molecular targets in diabetic kidney disease

Diabetic kidney disease is the leading cause of end-stage kidney disease, and it remains a major challenge. Many factors, such as glomerular hyperfiltration, oxidative stress, inflammation, hypoxia, and epigenetics, are associated with the progression of diabetic kidney disease; however, the whole mechanism is not yet completely understood. No specific treatment for diabetic kidney disease has been established, so new approaches are being explored extensively. Sodium-glucose cotransporter 2 inhibitors have shown renoprotective effects in several human clinical trials. Glucagon-like peptide 1 receptor agonists and mineralocorticoid receptor antagonists have been reported to be effective in diabetic kidney disease, and novel therapeutic candidates are also being examined. In the TSUBAKI trial, a nuclear factor erythroid 2-related factor 2 activator, bardoxolone methyl, improved the glomerular filtration rate of diabetic kidney disease patients. Similarly, new agents that act in the oxidative stress and inflammation pathways are of major interest, such as pentoxifylline, apoptosis signal-regulating kinase-1 inhibitors, C-C chemokine receptor 2 inhibitors, and Janus kinase-1/2 inhibitors. Endothelin-1 receptor A antagonists and soluble guanylate cyclase stimulators are also expected to affect renal hemodynamics. Some preclinical studies suggest that hypoxia-inducible factor prolyl hydroxylase inhibitors, which influence multiple inflammations and oxidative stress pathways, reduce albuminuria in diabetic kidney disease. Advanced glycation end-product inhibitors and treatments related to epigenetics have also shown promise as potential diabetic kidney disease treatments in preclinical studies. The discovery of new targets could provide new therapeutic options for overcoming diabetic kidney disease.

Macrophages in the kidney in health, injury and repair

Macrophages are a key component of the renal mononuclear phagocyte system, playing a major role in defense against infection, renal injury and repair. Yolk sac macrophage precursors seed the early embryonic kidney and are important for renal development. Later, renal macrophages are derived from hematopoietic stem cells and in adult life, there is a significant contribution from circulating monocytes, which is enhanced in response to infection or injury. Macrophages are highly plastic and can alter their phenotype in response to cues from parenchymal renal cells. Danger-associated molecules released from injured kidney cells may activate macrophages toward a pro-inflammatory phenotype, mediating further recruitment of inflammatory cells, exacerbating renal injury and activating renal fibroblasts to promote scarring. In acute kidney injury, once the injury stimulus has abated, macrophages may adopt a more reparative phenotype, dampening the immune response and promoting repair of renal tissue. However, in chronic kidney disease ongoing activation of pro-inflammatory monocytes and persistence of reparative macrophages leads to glomerulosclerosis and tubulointerstitial fibrosis, the hallmarks of end-stage kidney disease. Several strategies to inhibit the recruitment, activation and secretory products of pro-inflammatory macrophages have proven beneficial in pre-clinical models and are now undergoing clinical trials in patients with kidney disease. In addition, macrophages may be utilized in cell therapy as a "Trojan Horse" to deliver targeted therapies to the kidney. Single-cell RNA sequencing has identified a previously unappreciated spectrum of macrophage phenotypes, which may be selectively present in injury or repair, and ongoing functional analyses of these subsets may identify more specific targets for therapeutic intervention.

Can we cure diabetic kidney disease? Present and future perspectives from a nephrologist's point of view

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease (CKD) worldwide, contributing to a great burden across a variety of patient-reported and clinical outcomes. New interventions for DKD management have been established in recent years, unleashing a novel paradigm, in which kidney-dedicated trials yield informative and robust data to guide optimal clinical management. After unprecedented results from groundbreaking randomized controlled trials were released, a new scenario of evidence-based recommendations has evolved for the management of diabetic patients with CKD. The current guidelines place great emphasis on multidimensional and interdisciplinary approaches, but the challenges of implementation are just starting and will be pivotal to optimize clinical results and to understand the new threshold for residual risk in DKD. We thereby provide an updated review on recent advances in DKD management based on new guideline recommendations, summarizing recent evidence while projecting the landscape for innovative ongoing initiatives in the field. Specifically, we review current insights on the natural history, epidemiology, pathogenesis, and therapeutics of DKD, mapping the new scientific information into the recently released Kidney Disease - Improving Global Outcomes Guidelines translating results from major novel randomized controlled trials to the clinical practice. Additionally, we approach the landscape of new therapeutics in the field, summarizing ongoing phase IIb and III trials focused on DKD. Finally, reflecting on the past and looking into the future, we highlight unmet needs in the current DKD management based on real-world evidence and offer a nephrologist's perspective into the challenge of fostering continuous improvement on clinical and patient-reported outcomes for individuals living with DKD.

Cellular crosstalk of glomerular endothelial cells and podocytes in diabetic kidney disease

Diabetic kidney disease (DKD) is a serious microvascular complication of diabetes and is the leading cause of end-stage renal disease (ESRD). Persistent proteinuria is an important feature of DKD, which is caused by the destruction of the glomerular filtration barrier (GFB). Glomerular endothelial cells (GECs) and podocytes are important components of the GFB, and their damage can be observed in the early stages of DKD. Recently, studies have found that crosstalk between cells directly affects DKD progression, which has prospective research significance. However, the pathways involved are complex and largely unexplored. Here, we review the literature on cellular crosstalk of GECs and podocytes in the context of DKD, and highlight specific gaps in the field to propose future research directions. Elucidating the intricates of such complex processes will help to further understand the pathogenesis of DKD and develop better prevention and treatment options.

Midazolam Ameliorates Hyperglycemia-Induced Glomerular Endothelial Dysfunction by Inhibiting Transglutaminase 2 in Diabetes

Midazolam is an anesthetic widely used for anxiolysis and sedation; however, to date, a possible role for midazolam in diabetic kidney disease remains unknown. Here, we investigated the effect of midazolam on hyperglycemia-induced glomerular endothelial dysfunction and elucidated its mechanism of action in kidneys of diabetic mice and human glomerular microvascular endothelial cells (HGECs). We found that, in diabetic mice, subcutaneous midazolam treatment for 6 weeks attenuated hyperglycemia-induced elevation in urine albumin/creatinine ratios. It also ameliorated hyperglycemia-induced adherens junction disruption and subsequent microvascular leakage in glomeruli of diabetic mice. In HGECs, midazolam suppressed high glucose-induced vascular endothelial-cadherin disruption and endothelial cell permeability via inhibition of intracellular Ca²⁺ elevation and subsequent generation of reactive oxygen species (ROS) and transglutaminase 2 (TGase2) activation. Notably, midazolam also suppressed hyperglycemia-induced ROS generation and TGase2 activation in glomeruli of diabetic mice and markedly improved pathological alterations in glomerular ultrastructure in these animals. Analysis of kidneys from diabetic Tgm2^−/− mice further revealed that TGase2 played a critical role in microvascular leakage. Overall, our findings indicate that midazolam ameliorates hyperglycemia-induced glomerular endothelial dysfunction by inhibiting ROS-mediated activation of TGase2.

Novel Therapies for Kidney Disease in People With Diabetes

CONTEXT

The increasing burden of diabetic kidney disease (DKD) has led to the discovery of novel therapies.

OBJECTIVE

This review aims to summarize the results of recent clinical trials that test the efficacy of potential therapies for DKD.

METHODS

A systematized narrative review was performed utilizing the PubMed, Embase (Ovid), CINAHL, and Cochrane databases (January 2010 to January 2021). The included trials assessed the efficacy of specific medications using renal endpoints in adult participants with type 1 or 2 diabetes.

RESULTS

Fifty-three trials were identified. Large, multinational, and high-powered trials investigating sodium-glucose cotransporter 2 (SGLT2) inhibitors demonstrated improved renal outcomes, even in patients with established DKD. Trials examining incretin-related therapies also showed some improvement in renal outcomes. Additionally, mineralocorticoid receptor antagonists exhibited potential with multiple improved renal outcomes in large trials, including those involving participants with established DKD. Atrasentan, baricitinib, ASP8232, PF-04634817, CCX140-B, atorvastatin, fenofibrate, probucol, doxycycline, vitamin D, omega-3 fatty acids, silymarin, turmeric, total glucosides of paeony, and tripterygium wilfordii Hook F extract were all associated with some improved renal endpoints but need further exploration. While bardoxolone methyl was associated with a decrease in albuminuria, high rates of cardiovascular adverse effects curtailed further exploration into this agent. Selonsertib, allopurinol, praliciguat, palosuran, benfotiamine, and diacerein were not associated with improved renal outcomes.

CONCLUSION

Trials have yielded promising results in the search for new therapies to manage DKD. SGLT2 inhibitors and incretin-related therapies have demonstrated benefit and were associated with improved cardiovascular outcomes. Mineralocorticoid receptor antagonists are another class of agents with increasing evidence of benefits.

Structural Insights Support Targeting ASK1 Kinase for Therapeutic Interventions

Apoptosis signal-regulating kinase (ASK) 1, a member of the mitogen-activated protein kinase kinase kinase (MAP3K) family, modulates diverse responses to oxidative and endoplasmic reticulum (ER) stress and calcium influx. As a crucial cellular stress sensor, ASK1 activates c-Jun N-terminal kinases (JNKs) and p38 MAPKs. Their excessive and sustained activation leads to cell death, inflammation and fibrosis in various tissues and is implicated in the development of many neurological disorders, such as Alzheimer’s, Parkinson’s and Huntington disease and amyotrophic lateral sclerosis, in addition to cardiovascular diseases, diabetes and cancer. However, currently available inhibitors of JNK and p38 kinases either lack efficacy or have undesirable side effects. Therefore, targeted inhibition of their upstream activator, ASK1, stands out as a promising therapeutic strategy for treating such severe pathological conditions. This review summarizes recent structural findings on ASK1 regulation and its role in various diseases, highlighting prospects for ASK1 inhibition in the treatment of these pathologies.

Pharmacokinetics, Safety, and Tolerability of Selonsertib, an Apoptosis Signal-Regulating Kinase 1 (ASK1) Inhibitor, Following First-in-Human Single and Multiple Ascending Doses in Healthy Subjects

BACKGROUND

Selonsertib is a first-in-class inhibitor of apoptosis signal-regulating kinase 1 (ASK1) with therapeutic potential for fibrotic diseases. This phase I study evaluated the safety, tolerability, pharmacokinetics (PK), and food effect of selonsertib in healthy subjects.

METHODS

This was a double-blinded, randomized, placebo-controlled dose-escalation study. Healthy subjects received 1, 3, 10, 30, or 100 mg of selonsertib or placebo as single or multiple doses once daily for 14 days in the fasted state, or 30 mg or placebo single dose in the fed state. Blood and urine (single-dose cohorts only) samples for selonsertib PK were collected and safety was assessed throughout the study. Ex vivo pharmacodynamic (PD) assessment was performed in blood from a separate cohort of healthy donors using an auranofin-stimulated C-X-C motif chemokine ligand 1 (CXCL1) assay.

RESULTS

Overall, 107 subjects (83 active, 24 placebo) were enrolled and randomized to 11 cohorts. Selonsertib was generally well tolerated; adverse events were generally mild to moderate. Selonsertib was rapidly absorbed with dose-proportional PK of both parent and inactive metabolite GS-607509. There was no food effect on selonsertib PK. Renal excretion was a minor pathway of selonsertib elimination. Selonsertib half maximal effective concentration (EC₅₀) in human whole blood was determined to be 56 ng/mL.

CONCLUSIONS

Selonsertib exhibited a favorable PK profile amenable to once-daily dosing without regard to food. PD data suggest pharmacologically relevant exposures were achieved in the dose range evaluated. Study results support further clinical development of selonsertib.

Apoptosis signal-regulating kinase 1 (ASK1) inhibition reduces endothelial cytokine production without improving permeability after toll-like receptor 4 (TLR4) challenge

Sepsis represents a life-threatening event often mediated by the host's response to pathogens such as gram-negative organisms, which release the proinflammatory lipopolysaccharide (LPS). Within the endothelium, the mitogen-activated protein kinase (MAPK) pathway is an important driver of endothelial injury during sepsis, of which oxidant-sensitive apoptosis signal-regulating kinase 1 (ASK1) is postulated to be a critical upstream regulator. We hypothesized that ASK1 would play a key role in endothelial inflammation during bacterial challenge. Utilizing RNA sequencing data from patients and cultured human microvascular endothelial cells (HMVECs), ASK1 expression was increased in sepsis and after LPS challenge. Two ASK1 inhibitors, GS444217 and MSC2023964A, reduced cytokine production in HMVECs following LPS stimulation, but had no effect on permeability as measured by transendothelial electrical resistance and intercellular space. MAPKs are known to interact with endothelial nitric oxide synthase (eNOS) and ASK1 expression levels correlated with eNOS expression in patients with septic shock. In addition, eNOS physically interacted with ASK1, though this interaction was not altered by ASK1 inhibition, nor did inhibition alter MAPK p38 activity. Instead, among MAPKs, ASK1 inhibition only impaired LPS-induced JNK phosphorylation. The reduction in JNK activation caused by ASK1 inhibition impaired JNK-mediated cytokine production without affecting permeability. Thus, LPS triggers JNK-dependent cytokine production that requires ASK1 activation, but both its effects on permeability and activation of p38 are ASK1-independent. These data demonstrate how distinct MAPK signaling pathways regulate endothelial inflammatory outputs during acute infectious challenge.

Oxidative Stress in Non-Dialysis-Dependent Chronic Kidney Disease Patients

Background: Cardiovascular complications are the leading cause of morbidity and mortality at any stage of chronic kidney disease (CKD). Moreover, the high rate of cardiovascular mortality observed in these patients is associated with an accelerated atherosclerosis process that likely starts at the early stages of CKD. Thus, traditional and non-traditional or uremic-related factors represent a link between CKD and cardiovascular risk. Among non-conventional risk factors, particular focus has been placed on anaemia, mineral and bone disorders, inflammation, malnutrition and oxidative stress and, in this regard, connections have been reported between oxidative stress and cardiovascular disease in dialysis patients. Methods: We evaluated the oxidation process in different molecular lines (proteins, lipids and genetic material) in 155 non-dialysis patients at different stages of CKD and 45 healthy controls. To assess oxidative stress status, we analyzed oxidized glutathione (GSSG), reduced glutathione (GSH) and the oxidized/reduced glutathione ratio (GSSG/GSH) and other oxidation indicators, including malondialdehyde (MDA) and 8-oxo-2’-deoxyguanosine (8-oxo-dG). Results: An active grade of oxidative stress was found from the early stages of CKD onwards, which affected all of the molecular lines studied. We observed a heightened oxidative state (indicated by a higher level of oxidized molecules together with decreased levels of antioxidant molecules) as kidney function declined. Furthermore, oxidative stress-related alterations were significantly greater in CKD patients than in the control group. Conclusions: CKD patients exhibit significantly higher oxidative stress than healthy individuals, and these alterations intensify as eGFR declines, showing significant differences between CKD stages. Thus, future research is warranted to provide clearer results in this area.

New progress in drugs treatment of diabetic kidney disease

Diabetic kidney disease (DKD) is not only one of the main complications of diabetes, but also the leading cause of the end-stage renal disease (ESRD). The occurrence and development of DKD have always been a serious clinical problem that leads to the increase of morbidity and mortality and the severe damage to the quality of life of human beings. Controlling blood glucose, blood pressure, blood lipids, and improving lifestyle can help slow the progress of DKD. In recent years, with the extensive research on the pathological mechanism and molecular mechanism of DKD, there are more and more new drugs based on this, such as new hypoglycemic drugs sodium-glucose cotransporter 2 (SGLT2) inhibitors, glucagon-like peptide-1 (GLP-1) inhibitors, and dipeptidyl peptidase-4 (DPP-4) inhibitors with good efficacy in clinical treatment. Besides, there are some newly developed drugs, including protein kinase C (PKC) inhibitors, advanced glycation end product (AGE) inhibitors, aldosterone receptor inhibitors, endothelin receptor (ETR) inhibitors, transforming growth factor-β (TGF-β) inhibitors, Rho kinase (ROCK) inhibitors and so on, which show positive effects in animal or clinical trials and bring hope for the treatment of DKD. In this review, we sort out the progress in the treatment of DKD in recent years, the research status of some emerging drugs, and the potential drugs for the treatment of DKD in the future, hoping to provide some directions for clinical treatment of DKD.

Selonsertib Alleviates the Progression of Rat Osteoarthritis: An in vitro and in vivo Study

Osteoarthritis (OA) is a prevalent degenerative joint disease. Its development is highly associated with inflammatory response and apoptosis in chondrocytes. Selonsertib (Ser), the inhibitor of Apoptosis Signal-regulated kinase-1 (ASK1), has exhibited multiple therapeutic effects in several diseases. However, the exact role of Ser in OA remains unclear. Herein, we investigated the anti-arthritic effects as well as the potential mechanism of Ser on rat OA. Our results showed that Ser could markedly prevent the IL-1β-induced inflammatory reaction, cartilage degradation and cell apoptosis in rat chondrocytes. Meanwhile, the ASK1/P38/JNK and NFκB pathways were involved in the protective roles of Ser. Furthermore, intra-articular injection of Ser could significantly alleviate the surgery induced cartilage damage in rat OA model. In conclusion, our work provided insights into the therapeutic potential of Ser in OA, indicating that Ser might serve as a new avenue in OA treatment.

FOXO1-Mediated Downregulation of RAB27B Leads to Decreased Exosome Secretion in Diabetic Kidneys

Exosomes have been implicated in diabetic kidney disease (DKD), but the regulation of exosomes in DKD is largely unknown. Here, we have verified the decrease of exosome secretion in DKD and unveiled the underlying mechanism. In Boston University mouse proximal tubule (BUMPT) cells, high-glucose (HG) treatment led to a significant decrease in exosome secretion, which was associated with specific downregulation of RAB27B, a key guanosine-5'-triphosphatase in exosome secretion. Overexpression of RAB27B restored exosome secretion in HG-treated cells, suggesting a role of RAB27B downregulation in the decrease of exosome secretion in DKD. To understand the mechanism of RAB27B downregulation, we conducted bioinformatics analysis that identified FOXO1 binding sites in the Rab27b gene promoter. Consistently, HG induced phosphorylation of FOXO1 in BUMPT cells, preventing FOXO1 accumulation and activation in the nucleus. Overexpression of nonphosphorylatable, constitutively active FOXO1 led to the upregulation of RAB27B and an increase in exosome secretion in HG-treated cells. In vivo, compared with normal mice, diabetic mice showed increased FOXO1 phosphorylation, decreased RAB27B expression, and reduced exosome secretion. Collectively, these results unveil the mechanism of exosome dysfunction in DKD where FOXO1 is phosphorylated and inactivated in DKD, resulting in RAB27B downregulation and the decrease of exosome secretion.

Novel Anti-inflammatory and Anti-fibrotic Agents for Diabetic Kidney Disease-From Bench to Bedside

Chronic low-grade inflammation, now coined by the new paradigm as "metaflammation" or "metainflammation", has been linked to chronic kidney disease and its progression. In diabetes, altered metabolism denotes factors associated with the metabolic syndrome and hyperglycemia, among others. The interplay among hyperglycemia, oxidative stress, and inflammation in the pathogenesis of diabetic kidney disease (DKD) has been broadly explored. Identification of mediators of inflammatory processes involving macrophage infiltration, production of inflammasomes, release of cytokines, and activation of pertinent signaling pathways including mitogen-activated protein kinase, Jun N-terminal kinase, Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway (JAK/STAT), and apoptosis signal-regulating kinase 1 signaling mechanisms have enabled the development of therapeutic agents for DKD. This review describes the evidence supporting the contribution of the inflammatory response and fibrotic changes and focuses on selected, novel, promising drugs as well as repurposed drugs that have made it to phase 2, 3, or 4 of clinical trials in adults with type 2 diabetes mellitus and their potential to become an important part of our armamentarium to improve the management of DKD. Importantly, drugs that solely target inflammatory processes may be insufficient to fully optimize care of patients with DKD because of the complex nature of the disease.

Relationship between intact parathyroid hormone and all-cause death, cardiovascular events, and ectopic calcification in patients with diabetic kidney disease: A retrospective study

AIM

We aimed to investigate the relationship between intact parathyroid hormone (iPTH) levels and all-cause death, cardiovascular events, and ectopic calcification in patients with diabetic kidney disease (DKD).

METHODS

In this retrospective cohort study, we collected the clinical data of 508 patients with clinically diagnosed DKD. The primary and secondary outcomes were all-cause death or cardiovascular events and ectopic calcification, respectively. We used different regression methods to analyze the relationship between various clinical parameters and the two clinical outcomes.

RESULTS

We found that iPTH was a risk factor for all-cause death and cardiovascular events (hazards ration [HR]: 2.817, 95% confidence interval [CI]: 1.045-6.562, P = 0.016). Meanwhile, diabetes duration (HR: 1.090, 95% CI: 1.045-1.138, P < 0.0001), triglycerides (TG) (HR: 1.254, 95% CI: 1.049-1.499, P = 0.013), and iPTH (HR: 1.954, 95% CI: 1.001-3.813, P = 0.049) were independent risk factors for ectopic calcification. In contrast to patients with lower iPTH levels (iPTH < 31.7 pg/mL), patients with higher iPTH levels (iPTH ≥ 31.7 pg/mL) had increased ectopic calcification rate (P = 0.002) and decreased survival time (P < 0.001).

CONCLUSION

In patients with DKD, higher iPTH levels were significantly related to worsen clinical outcomes.

The role of inflammation in diabetic kidney disease

Diabetic kidney disease (DKD) has been the leading cause of chronic kidney disease for over 20 years. Yet, over these two decades, the clinical approach to this condition has not much improved beyond the administration of glucose-lowering agents, renin-angiotensin-aldosterone system blockers for blood pressure control, and lipid-lowering agents. The proportion of diabetic patients who develop DKD and progress to end-stage renal disease has remained nearly the same. This unmet need for DKD treatment is caused by the complex pathophysiology of DKD, and the difficulty of translating treatment from bench to bed, which further adds to the growing argument that DKD is not a homogeneous disease. To better capture the full spectrum of DKD in our design of treatment regimens, we need improved diagnostic tools that can better distinguish the subgroups within the condition. For instance, DKD is typically placed in the broad category of a non-inflammatory kidney disease. However, genome-wide transcriptome analysis studies consistently indicate the inflammatory signaling pathway activation in DKD. This review will utilize human data in discussing the potential for redefining the role of inflammation in DKD. We also comment on the therapeutic potential of targeted anti-inflammatory therapy for DKD.

Inhibition of apoptosis signal-regulating kinase 1 mitigates the pathogenesis of human immunodeficiency virus-associated nephropathy

BACKGROUND

Chronic kidney disease (CKD) is a common cause of morbidity and mortality in human immunodeficiency virus (HIV)-positive individuals. Among the HIV-related kidney diseases, HIV-associated nephropathy (HIVAN) is a rapidly progressive renal disease characterized by collapsing focal glomerulosclerosis (GS), microcystic tubular dilation, interstitial inflammation and fibrosis. Although the incidence of end-stage renal disease due to HIVAN has dramatically decreased with the widespread use of antiretroviral therapy, the prevalence of CKD continues to increase in HIV-positive individuals. Recent studies have highlighted the role of apoptosis signal-regulating kinase 1 (ASK1) in driving kidney disease progression through the activation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase and selective ASK-1 inhibitor GS-444217 was recently shown to reduce kidney injury and disease progression in various experimental models. Therefore we examined the efficacy of ASK1 antagonism by GS-444217 in the attenuation of HIVAN in Tg26 mice.

METHODS

GS-444217-supplemented rodent chow was administered in Tg26 mice at 4 weeks of age when mild GS and proteinuria were already established. After 6 weeks of treatment, the kidney function assessment and histological analyses were performed and compared between age- and gender-matched control Tg26 and GS-444217-treated Tg26 mice.

RESULTS

GS-444217 attenuated the development of GS, podocyte loss, tubular injury, interstitial inflammation and renal fibrosis in Tg26 mice. These improvements were accompanied by a marked reduction in albuminuria and improved renal function. Taken together, GS-4442217 attenuated the full spectrum of HIVAN pathology in Tg26 mice.

CONCLUSIONS

ASK1 signaling cascade is central to the development of HIVAN in Tg26 mice. Our results suggest that the select inhibition of ASK1 could be a potential adjunctive therapy for the treatment of HIVAN.