TRAIL deficiency contributes to diabetic nephropathy in fat-fed ApoE-/- mice

Apoptotic cell death in disease-Current understanding of the NCCD 2023

Apoptosis is a form of regulated cell death (RCD) that involves proteases of the caspase family. Pharmacological and genetic strategies that experimentally inhibit or delay apoptosis in mammalian systems have elucidated the key contribution of this process not only to (post-)embryonic development and adult tissue homeostasis, but also to the etiology of multiple human disorders. Consistent with this notion, while defects in the molecular machinery for apoptotic cell death impair organismal development and promote oncogenesis, the unwarranted activation of apoptosis promotes cell loss and tissue damage in the context of various neurological, cardiovascular, renal, hepatic, infectious, neoplastic and inflammatory conditions. Here, the Nomenclature Committee on Cell Death (NCCD) gathered to critically summarize an abundant pre-clinical literature mechanistically linking the core apoptotic apparatus to organismal homeostasis in the context of disease.

The Prognostic, Diagnostic, and Therapeutic Potential of TRAIL Signalling in Cardiovascular Diseases

TNF-related apoptosis-inducing ligand (TRAIL) was originally discovered, almost 20 years ago, for its ability to kill cancer cells. More recent evidence has described pleiotropic functions, particularly in the cardiovascular system. There is potential for TRAIL concentrations in the circulation to act as prognostic and/or diagnostic factors for cardiovascular diseases (CVD). Pre-clinical studies also describe the therapeutic capacity for TRAIL signals, particularly in the context of atherosclerotic disease and diseases of the myocardium. Because diabetes mellitus significantly contributes to the progression and pathogenesis of CVDs, in this review we highlight recent evidence for the prognostic, diagnostic, and therapeutic potential of TRAIL signals in CVDs, and where relevant, the impact of diabetes mellitus. A greater understanding of how TRAIL signals regulate cardiovascular protection and pathology may offer new diagnostic and therapeutic avenues for patients suffering from CVDs.

Broadening horizons in mechanisms, management, and treatment of diabetic kidney disease

Diabetic kidney disease (DKD) is the first cause of end-stage kidney disease in patients with diabetes and its prevalence is increasing worldwide. It encompasses histological alterations that mainly affect the glomerular filtration unit, which include thickening of the basement membrane, mesangial cell proliferation, endothelial alteration, and podocyte injury. These morphological abnormalities further result in a persistent increase of urinary albumin-to-creatinine ratio and in a reduction of the estimated glomerular filtration rate. Several molecular and cellular mechanisms have been recognized, up to date, as major players in mediating such clinical and histological features and many more are being under investigation. This review summarizes the most recent advances in understanding cell death mechanisms, intracellular signaling pathways and molecular effectors that play a role in the onset and progression of diabetic kidney damage. Some of those molecular and cellular mechanisms have been already successfully targeted in preclinical models of DKD and, in some cases, strategies have been tested in clinical trials. Finally, this report sheds light on the relevance of novel pathways that may become therapeutic targets for future applications in DKD.

TRAIL and EGFR Pathways Targeting microRNAs are Predominantly Regulated in Human Diabetic Nephropathy

BACKGROUND

Unbiased microRNA profiling of renal tissue and urinary extracellular vesicles (uEVs) from diabetic nephropathy (DN) subjects may unravel novel targets with diagnostic and therapeutic potential. Here we used the miRNA profile of uEVs and renal biopsies from DN subjects available on the GEO database.

METHODS

The miR expression profiles of kidney tissue (GSE51674) and urinary exosomes (GSE48318) from DN and control subjects were obtained by GEO2R tools from Gene Expression Omnibus (GEO) databases. Differentially expressed miRNAs in DN samples, relative to controls, were identified using a bioinformatic pipeline. Targets of miRs commonly regulated in both sample types were predicted by miRWalk, followed by functional gene enrichment analysis. Gene targets were identified by MiRTarBase, TargetScan and MiRDB.

RESULTS

Eight miRs, including let-7c, miR-10a, miR-10b and miR-181c, were significantly regulated in kidney tissue and uEVs in DN subjects versus controls. The top 10 significant pathways targeted by these miRs included TRAIL, EGFR, Proteoglycan syndecan, VEGF and Integrin Pathway. Gene target analysis by miRwalk upon validation using ShinyGO 70 targets with significant miRNA-mRNA interaction.

CONCLUSION

In silico analysis showed that miRs targeting TRAIL and EGFR signaling are predominately regulated in uEVs and renal tissue of DN subjects. After wet-lab validation, the identified miRstarget pairs may be explored for their diagnostic and/or therapeutic potential in diabetic nephropathy.

Repositioning the Role of Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) on the TRAIL to the Development of Diabetes Mellitus: An Update of Experimental and Clinical Evidence

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF protein superfamily, represents a multifaceted cytokine with unique biological features including both proapoptotic and pro-survival effects in different cell types depending on receptor interactions and local stimuli. Beyond its extensively studied anti-tumor and immunomodulatory properties, a growing body of experimental and clinical evidence over the past two decades suggests a protective role of TRAIL in the development of type 1 (T1DM) and type 2 (T2DM) diabetes mellitus. This evidence can be briefly summarized by the following observations: (i) acceleration and exacerbation of T1DM and T2DM by TRAIL blockade or genetic deficiency in animal models, (ii) prevention and amelioration of T1DM and T2DM with recombinant TRAIL treatment or systemic TRAIL gene delivery in animal models, (iii) significantly reduced circulating soluble TRAIL levels in patients with T1DM and T2DM both at disease onset and in more advanced stages of diabetes-related complications such as cardiovascular disease and diabetic nephropathy, (iv) increase of serum TRAIL levels in diabetic patients after initiation of antidiabetic treatment and metabolic improvement. To explore the underlying mechanisms and provide mechanistic links between TRAIL and diabetes, a number of animal and in vitro studies have reported direct effects of TRAIL on several tissues involved in diabetes pathophysiology such as pancreatic islets, skeletal muscle, adipose tissue, liver, kidney, and immune and vascular cells. Residual controversy remains regarding the effects of TRAIL on adipose tissue homeostasis. Although the existing evidence is encouraging and paves the way for investigating TRAIL-related interventions in diabetic patients with cardiometabolic abnormalities, caution is warranted in the extrapolation of animal and in vitro data to the clinical setting, and further research in humans is imperative in order to uncover all aspects of the TRAIL-diabetes relationship and delineate its therapeutic implications in metabolic disease.

Monocytes as a convergent nanoparticle therapeutic target for cardiovascular diseases

Due to the increasing population of individualswith cardiovascular diseases and related comorbidities, there is an increasing need for development of synergistic therapeutics. Monocytes are implicated in a broad spectrum of diseases and can serve as a focal point for therapeutic targeting. This review discusses the role of monocytes in cardiovascular diseases and highlights trends in monocyte targets nanoparticles in three cardiovascular-related diseases: Diabetes, Atherosclerosis, and HIV. Finally, the review offers perspectives on how to develop nanoparticle monocyte targeting strategies that can be beneficial for treating co-morbidities.

Hyperlipidemia Influences the Accuracy of Glucometer-Measured Blood Glucose Concentrations in Genetically Diverse Mice

BACKGROUND

Glucometers are widely used in animal research due to simplicity and ease of utilization, but their accuracy in blood glucose assessment for hyperlipidemic mice is unknown.

METHODS

Here, we compared blood glucose levels measured by a glucometer with plasma glucose levels measured by a standard enzymatic assay for 325 genetically diverse F2 mice derived from LP and BALB/c (BALB) Apoe^-/- mice. Non-fasting glucose levels were measured before initiation of a Western diet and after 11 weeks on the diet.

RESULTS

On chow diet, lab-measured plasma glucose levels were 279.5 ± 42.6 mg/dl (mean ± SD), while blood glucose values measured by glucometer were 138.7 ± 16.6 mg/dl. The two measures had no correlation (R² = 0.006, p = 0.167). On the Western diet, plasma glucose levels rose to 351.1 ± 121.6 mg/dl, while glucometer-measured blood glucose fell to 128.7 ± 27.9 mg/dl. The two measures showed a moderate correlation (R² = 0.111, p = 3.1E-9). Lab-measured plasma glucose showed strong positive correlations with plasma triglyceride and non-high-density lipoprotein cholesterol levels, while glucometer-measured blood glucose showed an inverse correlation with non-high-density lipoprotein levels on the chow diet.

CONCLUSIONS

Our results indicate that hyperlipidemia affects the accuracy of glucometers in measuring blood glucose levels of mice.

TRAIL treatment prevents renal morphological changes and TGF-β-induced mesenchymal transition associated with diabetic nephropathy

BACKGROUND

TNF-related apoptosis-inducing ligand (TRAIL) has attracted attention not only as an anti-cancer agent, but also as a potential treatment for diabetes. Animal studies have shown that TRAIL delivery ameliorated glucose control in type 1 and type 2 diabetes. It is currently unknown whether TRAIL positive effects are maintained in more severe forms of type 2 diabetes, and whether they include renoprotection. Our study aimed at evaluating TRAIL effects in a severe form of type 2 diabetes with nephropathy.

MATERIALS AND METHODS

A total of 20 db/db mice were treated with saline or TRAIL twice per week for 12 weeks. In parallel, renal tubular epithelial cells were cultured with TGF-β1 in the presence and absence of TRAIL, with and without silencing TRAIL-specific receptor (DR5) and leptin receptor.

RESULTS

TRAIL did not improve glucose control, but it significantly reduced circulating interleukin (IL)-6 and resistin. In the kidney, TRAIL treatment significantly ameliorated glomerular and tubular morphology with an improvement in kidney function, but no effect on proteinuria. Our in vitro studies on TGF-β1-treated cells, showed that by binding to DR5, TRAIL rescued normal tubular cell morphology, increasing E-cadherin and reducing α-smooth muscle actin (SMA) expression, with no effects on cell viability. Interestingly, both in vivo and in vitro, TRAIL reduced the accumulation of the autophagy substrate p62.

CONCLUSIONS

Our data confirm TRAIL protective effects against organ damage and shed light on to promising anti-fibrotic actions, which are independent of glucose control. TRAIL anti-fibrotic actions might be due to the rescue of autophagy in diabetes.

A "Western Diet" promotes symptoms of hepatic steatosis in spontaneously hypertensive rats

Systemic hypertension, characterized by elevated blood pressure ≥140/90 mm Hg, is a major modifiable risk factor for cardiovascular disease. Hypertension also associates with non-alcoholic fatty liver disease (NAFLD), which is becoming common due to a modern diet and lifestyle. The aim of the present study was to examine whether a high-fat "Western" diet had effects on hypertension and associated NAFLD. Normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) were placed on a normal chow or high-fat diet for 8 weeks; blood pressure was measured fortnightly and body weight recorded weekly. As expected, SHR had elevated blood pressure compared to WKY. Diet did not influence blood pressure. Compared to SHR, WKY rats gained more weight, associating with increased white adipose tissue weight. Normotensive rats also had higher plasma cholesterol and triglycerides in response to a "Western" diet, with no changes in plasma glucose levels. Neither strain developed atherosclerosis. Interestingly, high-fat diet-fed SHR had increased liver weight, associating with a significant level of hepatic lipid accumulation not observed in WKY. Further, they exhibited hepatocellular ballooning and increased hepatic inflammation, indicative of steatohepatitis. These findings suggest that a high-fat "Western" diet promotes features of NAFLD in SHR, but not WKY rats. Importantly, the high-fat diet had no effect on blood pressure.

Vascular transcriptome landscape of Trail-/- mice: Implications and therapeutic strategies for diabetic vascular disease

Circulating plasma TRAIL levels are suppressed in patients with cardiovascular and diabetic diseases. To identify novel targets in vascular metabolic diseases, genome-wide transcriptome of aortic tissue from Trail^-/- versus Trail^+/+ mice were interrogated. We found 861 genes differentially expressed with TRAIL deletion. Gene enrichment analyses showed many of these genes were related to inflammation, cell-to-cell cytoskeletal interactions, and transcriptional modulation. We identified vascular protective and pathological gene clusters, with Ifi205 as the most significantly reduced vascular protective gene, whereas Glut1, the most significantly increased pathological gene with TRAIL deletion. We hypothesized that therapeutic targets could be devised from such integrated analysis and validated our findings from vascular tissues of diabetic mice. From the differentially expressed gene targets, enriched transcription factor (TF) and microRNA binding motifs were identified. The top two TFs were Elk1 and Sp1, with enrichment to eight gene targets common to both. miR-520d-3p and miR-377-3p were the top enriched microRNAs with TRAIL deletion; with four overlapping genes enriched for both microRNAs. Our findings offer an alternate in silico approach for therapeutic target identification and present a deeper understanding of gene signatures and pathways altered with TRAIL suppression in the vasculature.

Beyond adiponectin and leptin: adipose tissue-derived mediators of inter-organ communication

The breakthrough discoveries of leptin and adiponectin more than two decades ago led to a widespread recognition of adipose tissue as an endocrine organ. Many more adipose tissue-secreted signaling mediators (adipokines) have been identified since then, and much has been learned about how adipose tissue communicates with other organs of the body to maintain systemic homeostasis. Beyond proteins, additional factors, such as lipids, metabolites, noncoding RNAs, and extracellular vesicles (EVs), released by adipose tissue participate in this process. Here, we review the diverse signaling mediators and mechanisms adipose tissue utilizes to relay information to other organs. We discuss recently identified adipokines (proteins, lipids, and metabolites) and briefly outline the contributions of noncoding RNAs and EVs to the ever-increasing complexities of adipose tissue inter-organ communication. We conclude by reflecting on central aspects of adipokine biology, namely, the contribution of distinct adipose tissue depots and cell types to adipokine secretion, the phenomenon of adipokine resistance, and the capacity of adipose tissue to act both as a source and sink of signaling mediators.

TRAIL, OPG, and TWEAK in kidney disease: biomarkers or therapeutic targets?

Ligands and receptors of the tumor necrosis factor (TNF) superfamily regulate immune responses and homeostatic functions with potential diagnostic and therapeutic implications. Kidney disease represents a global public health problem, whose prevalence is rising worldwide, due to the aging of the population and the increasing prevalence of diabetes, hypertension, obesity, and immune disorders. In addition, chronic kidney disease is an independent risk factor for the development of cardiovascular disease, which further increases kidney-related morbidity and mortality. Recently, it has been shown that some TNF superfamily members are actively implicated in renal pathophysiology. These members include TNF-related apoptosis-inducing ligand (TRAIL), its decoy receptor osteoprotegerin (OPG), and TNF-like weaker inducer of apoptosis (TWEAK). All of them have shown the ability to activate crucial pathways involved in kidney disease development and progression (e.g. canonical and non-canonical pathways of the transcription factor nuclear factor-kappa B), as well as the ability to regulate cell proliferation, differentiation, apoptosis, necrosis, inflammation, angiogenesis, and fibrosis with double-edged effects depending on the type and stage of kidney injury. Here we will review the actions of TRAIL, OPG, and TWEAK on diabetic and non-diabetic kidney disease, in order to provide insights into their full clinical potential as biomarkers and/or therapeutic options against kidney disease.

TRAIL-Expressing Monocyte/Macrophages Are Critical for Reducing Inflammation and Atherosclerosis

Circulating tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) levels are reduced in patients with cardiovascular disease, and TRAIL gene deletion in mice exacerbates atherosclerosis and inflammation. How TRAIL protects against atherosclerosis and why levels are reduced in disease is unknown. Here, multiple strategies were used to identify the protective source of TRAIL and its mechanism(s) of action. Samples from patients with coronary artery disease and bone-marrow transplantation experiments in mice lacking TRAIL revealed monocytes/macrophages as the main protective source. Accordingly, deletion of TRAIL caused a more inflammatory macrophage with reduced migration, displaying impaired reverse cholesterol efflux and efferocytosis. Furthermore, interleukin (IL)-18, commonly increased in plasma of patients with cardiovascular disease, negatively regulated TRAIL transcription and gene expression, revealing an IL-18-TRAIL axis. These findings demonstrate that TRAIL is protective of atherosclerosis by modulating monocyte/macrophage phenotype and function. Manipulating TRAIL levels in these cells highlights a different therapeutic avenue in the treatment of cardiovascular disease.

Tumour necrosis factor-related apoptosis-inducing ligand expression in patients with diabetic nephropathy

Objective:

The objective of this study was to evaluate the expression profile of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) in patients with diabetic nephropathy (DN).

Methods:

A total of 126 Chinese subjects were enrolled in this study, including 42 patients with diabetes mellitus (DM), 42 patients with DN and 42 healthy controls. Real-time polymerase chain reaction was performed to analyze levels of TRAIL mRNA in peripheral blood mononuclear cells (PBMCs). Serum levels of soluble TRAIL (sTRAIL) and various cytokines were detected with a commercially available enzyme-linked immunosorbent assay kit.

Results:

Compared with the control group, the levels of TRAIL mRNA in PBMCs and sTRAIL in sera were both significantly decreased in the DM and DN patients (P < 0.05). Conversely, levels of interleukin (IL)-1, IL-6, tumour necrosis factor-α and monocyte chemotactic protein-1 were higher in the DN group than in the control group. Serum levels of TRAIL positively correlated with TRAIL mRNA levels in all of the subjects examined (P < 0.05).

Conclusions:

These results provide support and a theoretical basis for further research of TRAIL in regard to the pathogenesis of DN.

TRAIL protects against endothelial dysfunction in vivo and inhibits angiotensin-II-induced oxidative stress in vascular endothelial cells in vitro

The vascular endothelium is critical for maintenance of cardiovascular homeostasis. Endothelial dysfunction is a key event of atherosclerosis, with oxidative stress mediated by reactive oxygen species (ROS) playing a major role. Tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is increasingly recognised to play a protective role in atherosclerosis, however the molecular mechanisms by which it exerts its beneficial effects are unclear. Here we examined if TRAIL could attenuate vascular oxidative stress and improve endothelial cell (EC) function. In coronary artery disease patients, plasma TRAIL levels were significantly reduced compared to healthy individuals, and negatively correlated with the levels of circulating 8-iso Prostaglandin F_2α, a marker of in vivo oxidative stress. In vivo, high-fat fed, atherosclerotic Trail^-/-Apoe^-/- mice exhibited a significant impairment in endothelial-dependent vasorelaxation, which correlated with increased vascular ROS and 4-hydroxynonenal compared to Apoe^-/- mice. Endothelial permeability measured by Evan's blue dye extravasation was increased in several organs of Trail^-/- mice compared to wild-type mice, which correlated with a decrease in VE-cadherin expression. In vitro in ECs, angiotensin II (AngII)-induced ROS generation involving the mitochondria, NADPH oxidase-4 (NOX-4) and eNOS, was inhibited by pre-treatment with TRAIL. Furthermore, AngII-augmented VCAM-1 expression and monocyte adhesion to ECs was inhibited by TRAIL. Finally, AngII reduced VE-cadherin expression and redistributed this protein, all of which was brought back to baseline by TRAIL pre-treatment. These findings demonstrate for the first time that TRAIL protects against several forms of endothelial dysfunction involving its ability to control EC ROS generation. Understanding the role TRAIL plays in normal physiology and disease, may lead to potential new therapies to improve endothelial function and atherosclerosis.

Relationship between low levels of circulating TRAIL and atheromatosis progression in patients with chronic kidney disease

Background

Chronic kidney disease (CKD) patients experience a high risk of cardiovascular disease (CV); however, the factors involved in CV-related morbidity and mortality in these patients have not been fully defined. Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) is a cytokine, which exhibits pleiotropic activities on endothelial, vascular smooth muscle and inflammatory cells, with relevant effects on atheromatous plaque formation. On this basis, the present study aims to investigate the role of TRAIL in atheromatosis progression in CKD patients.

Methods

Circulating TRAIL levels were measured in 378 CKD patients belonging to the Spanish National Observatory of Atherosclerosis in Nephrology (NEFRONA) study. All patients were free of previous CV events. Carotid and femoral B-mode ultrasound was performed to detect the presence of plaque at baseline and after 24 months of follow-up.

Results

The lowest levels of TRAIL at baseline were significantly (p<0.05) associated with the appearance, after 24 months of follow-up, of at least two new atheromatous plaques in all territories and of one new plaque in the carotid artery, even after adjusting for CV risk factors. In addition, the patients with low levels of TRAIL at baseline were characterized by the presence of at least one hypoechoic plaque in the carotid artery. This association was significant (p<0.05) even after adjusting for CKD stage.

Conclusions

Overall, the results of our study suggest TRAIL as an assertable independent prognostic biomarker for atheromatosis plaque formation in CKD patients. This observation further supports the potential role of TRAIL for the prevention/treatment of CV disease.

Non-alcoholic fatty liver disease, vascular inflammation and insulin resistance are exacerbated by TRAIL deletion in mice

Non-alcoholic fatty liver disease (NAFLD) incorporates steatosis, non-alcoholic steato-hepatitis (NASH) and liver cirrhosis, associating with diabetes and cardiovascular disease (CVD). TNF-related apoptosis-inducing ligand (TRAIL) is protective of CVD. We aimed to determine whether TRAIL protects against insulin resistance, NAFLD and vascular injury. Twelve-week high fat diet (HFD)-fed Trail^−/− mice had increased plasma cholesterol, insulin and glucose compared to wildtype. Insulin tolerance was impaired with TRAIL-deletion, with reduced p-Akt, GLUT4 expression and glucose uptake in skeletal muscle. Hepatic triglyceride content, inflammation and fibrosis were increased with TRAIL-deletion, with elevated expression of genes regulating lipogenesis and gluconeogenesis. Moreover, Trail^−/− mice exhibited reduced aortic vasorelaxation, impaired insulin signaling, and >20-fold increased mRNA expression for IL-1β, IL-6, and TNF-α. In vitro, palmitate treatment of hepatocytes increased lipid accumulation, inflammation and fibrosis, with TRAIL mRNA significantly reduced. TRAIL administration inhibited palmitate-induced hepatocyte lipid uptake. Finally, patients with NASH had significantly reduced plasma TRAIL compared to control, simple steatosis or obese individuals. These findings suggest that TRAIL protects against insulin resistance, NAFLD and vascular inflammation. Increasing TRAIL levels may be an attractive therapeutic strategy, to reduce features of diabetes, as well as liver and vascular injury, so commonly observed in individuals with NAFLD.

TNF Receptor 1/2 Predict Heart Failure Risk in Type 2 Diabetes Mellitus Patients

Inflammation plays an important role in heart failure and diabetes mellitus. Traditional serum markers have limited predictive value in heart failure and diabetes. TNFR1 and TNFR2 (TNFR1/2) have been proven to be strongly associated with heart failure and diabetes complications. This study aimed to assess the association of sTNFR1 and sTNFR2 levels and incidental HF risk in diabetes patients.We detected the mRNA, protein, and serum expression of TNFR1/2, their downstream signaling pathway protein NF-kB, and JNK expression and some traditional serum inflammatory markers in a heart failure group without diabetes mellitus or abnormal glucose tolerance (n = 84), a diabetes mellitus group without heart failure (n = 86), and a heart failure with diabetes mellitus group (n = 86).TNFR1/2 were significantly higher in patients with heart failure and diabetes mellitus based on mRNA expression to protein expression and serum expression. However, there were no differences in mRNA, protein, and serum levels of TNFR1/2 between the HF group and DM group. Furthermore, there were no differences between the groups in some traditional serum inflammatory markers.This study demonstrated higher expressions of TNFR, NF-kB, and JNK in patients with heart failure and diabetes mellitus. Compared with traditional serum markers, TNFR1 and TNFR2 are associated with heart failure risk in type 2 diabetes mellitus patients.

Therapeutic applications of TRAIL receptor agonists in cancer and beyond

TRAIL/Apo-2L is a member of the TNF superfamily first described as an apoptosis-inducing cytokine in 1995. Similar to TNF and Fas ligand, TRAIL induces apoptosis in caspase-dependent manner following TRAIL death receptor trimerization. Because tumor cells were shown to be particularly sensitive to this cytokine while normal cells/tissues proved to be resistant along with being able to synthesize and release TRAIL, it was rapidly appreciated that TRAIL likely served as one of our major physiologic weapons against cancer. In line with this, a number of research laboratories and pharmaceutical companies have attempted to exploit the ability of TRAIL to kill cancer cells by developing recombinant forms of TRAIL or TRAIL receptor agonists (e.g., receptor-specific mAb) for therapeutic purposes. In this review article we will describe the biochemical pathways used by TRAIL to induce different cell death programs. We will also summarize the clinical trials related to this pathway and discuss possible novel uses of TRAIL-related therapies. In recent years, the physiological importance of TRAIL has expanded beyond being a tumoricidal molecule to one critical for a number of clinical settings - ranging from infectious disease and autoimmunity to cardiovascular anomalies. We will also highlight some of these conditions where modulation of the TRAIL/TRAIL receptor system may be targeted in the future.

Elevation of circulating TNF receptors 1 and 2 increases the risk of end-stage renal disease in American Indians with type 2 diabetes

In Caucasians with type 2 diabetes, circulating TNF receptors 1 (TNFR1) and 2 (TNFR2) predict end-stage renal disease (ESRD). Here we examined this relationship in a longitudinal cohort study of American Indians with type 2 diabetes with measured glomerular filtration rate (mGFR, iothalamate) and urinary albumin-to-creatinine ratio (ACR). ESRD was defined as dialysis, kidney transplant, or death attributed to diabetic kidney disease. Age-gender-adjusted incidence rates and incidence rate ratios of ESRD were computed by Mantel-Haenszel stratification. The hazard ratio of ESRD was assessed per interquartile range increase in the distribution of each TNFR after adjusting for baseline age, gender, mean blood pressure, HbA1c, ACR, and mGFR. Among the 193 participants, 62 developed ESRD and 25 died without ESRD during a median follow-up of 9.5 years. The age-gender-adjusted incidence rate ratio of ESRD was higher among participants in the highest versus lowest quartile for TNFR1 (6.6, 95% confidence interval (CI) 3.3-13.3) or TNFR2 (8.8, 95% CI 4.3-18.0). In the fully adjusted model, the risk of ESRD per interquartile range increase was 1.6 times (95% CI 1.1-2.2) as high for TNFR1 and 1.7 times (95% CI 1.2-2.3) as high for TNFR2. Thus, elevated serum concentrations of TNFR1 or TNFR2 are associated with increased risk of ESRD in American Indians with type 2 diabetes after accounting for traditional risk factors including ACR and mGFR.

Correlation between type 1 diabetic nephropathy and insulin resistance

AIM: To perform a quantitative test for urinary protein and different renal function indexes and explore the expression and phosphorylation of relevant proteins in the insulin signal pathway.

METHODS: Controls and cases at a ratio of 1:1 were included in this prospective randomized controlled clinical study. There were 40 patients with diabetic nephropathy (DN) and 40 normal cases with comparable age. Plasma samples were collected from the subjects to detect the protein expression of insulin receptor substrate (IRS)-2, p-IRS-2, AKT, and p-AKT by Western blot. The correlations of the quantity of urinary protein, RBF and GFR with homeostasis model assessment-insulin resistance (HOMA-IR), homeostasis model assessment-insulin sensitive index (HOMA-ISI) and homeostasis model assessment-pancreatic beta-cell function (HOMA-β%) were analyzed.

RESULTS: The ratios of p-IRS-2/IRS-2 and p-AKT/AKT decreased significantly in the DN group compared with the normal group (P < 0.05). There was a positive correlation between the quantity of urinary protein and HOMA-IR (P < 0.05) and a negative correlation between the quantity of urinary protein and HOMA-ISI (P < 0.05).

CONCLUSION: The ratios of p-IRS-2/IRS-2 and p-AKT/AKT decrease in DN patients. There exist correlations between the quantity of urinary protein and HOMA-IR and HOMA-ISI. These results indicate that the decrease of HOMA-ISI, the increase of HOMA-IR and the blockage of the insulin signal pathway may be key factors that cause DN.

Ventral prostate fibrosis in the Akita mouse is associated with macrophage and fibrocyte infiltration

A higher incidence of lower urinary tract symptoms (LUTS) among diabetic men is unexplained. Recently, prostate inflammation and fibrosis have been implicated as major contributing factors to bladder outlet obstruction and LUTS. We characterized the inflammatory cell infiltrate and collagen content of the anterior, dorsal, and ventral lobes of 18-week-old DBA2J.Ins2-Akita mice (Akita) and age-matched control mice. We performed hematoxylin and eosin staining to score tissue injury and inflammation, picrosirius red staining to quantitate collagen content, and immunostaining to identify monocytes/macrophages and infiltrating fibrocytes. We observed significantly greater numbers of monocytes/macrophages and fibrocytes specifically in the ventral prostate of the Akita mice and found that this was associated with significant greater collagen content specifically in the ventral prostate of the Akita mice. These observations support the inference that diabetes elicits monocyte/macrophage infiltration and collagen accumulation in the prostate and suggest that further study of Akita mice may inform translational studies of diabetes in the genesis prostatic inflammation, prostatic fibrosis, and LUTS.