MicroRNA-5010-5p ameliorates high-glucose induced inflammation in renal tubular epithelial cells by modulating the expression of PPP2R2D.

INTRODUCTION: We previously reported the significant upregulation of eight circulating exosomal microRNAs (miRNAs) in patients with diabetic kidney disease (DKD). However, their specific roles and molecular mechanisms in the kidney remain unknown. Among the eight miRNAs, we evaluated the effects of miR-5010-5p on renal tubular epithelial cells under diabetic conditions in this study. RESEARCH DESIGN AND METHODS: We transfected the renal tubular epithelial cell line, HK-2, with an miR-5010-5p mimic using recombinant plasmids. The target gene of hsa-miR-5010-5p was identified using a dual-luciferase assay. Cell viability was assessed via the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. Moreover, mRNA and protein expression levels were determined via real-time PCR and western blotting, respectively. RESULTS: High glucose levels did not significantly affect the intracellular expression of miR-5010-5p in HK-2 cells. Transfection of the miR-5010-5p mimic caused no change in cell viability. However, miR-5010-5p-transfected HK-2 cells exhibited significantly decreased expression levels of inflammatory cytokines, such as the monocyte chemoattractant protein-1, interleukin-1ß, and tumor necrosis factor-ɑ, under high-glucose conditions. These changes were accompanied by the restored expression of phosphorylated AMP-activated protein kinase (AMPK) and decreased phosphorylation of nuclear factor-kappa B. Dual-luciferase assay revealed that miR-5010-5p targeted the gene, protein phosphatase 2 regulatory subunit B delta (PPP2R2D), a subunit of protein phosphatase 2A, which modulates AMPK phosphorylation. CONCLUSIONS: Our findings suggest that increased miR-5010-5p expression reduces high glucose-induced inflammatory responses in renal tubular epithelial cells via the regulation of the target gene, PPP2R2D, which modulates AMPK phosphorylation. Therefore, miR-5010-5p may be a promising therapeutic target for DKD.

Late-Onset Granulomatous Pneumocystis jirovecii Pneumonia in A Renal Transplant Recipient: A Clinical Grand Round Conference Case in 2022.

Late-onset Pneumocystis jirovecii pneumonia (PCP) can be developed in solid organ transplant (SOT) patients. Granulomatous P. jirovecii pneumonia (GPCP) can occur in immunocompromised patients, but has rarely been reported in SOT recipients. The diagnosis of GPCP is difficult since the sensitivity of sputum and bronchoalveolar lavage is low and atypical patterns are shown. A 60-year-old man, who had undergone renal transplantation 24 years ago presented with nodular and patchy lung lesions. He was asymptomatic and stable. After empirical treatment with a fluoroquinolone, the condition partially resolved but relapsed 4 months later. The pulmonary nodule was resected, and GPCP was confirmed. The pathogenesis of GPCP remains unclear, but in SOT recipients presenting with an atypical lung pattern, GPCP should be considered. This case was discussed at the Grand Clinical Ground of the Korean Society of Infectious Disease conference on November 3, 2022.

Association of glomerular hyperfiltration with carotid artery plaque in the general population.

BACKGROUND AND AIMS: Glomerular hyperfiltration (GHF) is a hemodynamic change of the kidney as an adaptive response to nephron loss. Although GHF is associated with metabolic risk factors and cardiovascular disease (CVD), the mechanisms that explain these relationships remain largely unknown. This is partially caused by a non-unified definition of GHF based on pathophysiologic vascular changes. Thus, the objective of this study was to evaluate the association between various definitions of GHF and carotid plaque in a health checkup cohort. METHODS: A total of 4493 individuals without history of CVD who had carotid ultrasonography (USG) results available between January 2016 and June 2018 were enrolled. GHF was defined as >90th percentile of eGFR residuals after adjusting for confounding factors. Carotid plaque score was calculated based on carotid USG results. RESULTS: Of 4493 individuals (mean age, 52.3 ± 10.1 years; 3224 [71.8%] males), 449 subjects were included in the GHF group (mean eGFR, 107.0 ± 7.1 ml/min/1.73 m2) and 4044 subjects were included in the non-GHF group (mean eGFR, 92.5 ± 12.3 ml/min/1.73 m2). When the GHF group was compared to the non-GHF group, GHF was associated with the presence of significant carotid plaque (carotid plaque score ≥2) (adjusted OR: 1.46; 95% CI: 1.16 to 1.83; p = 0.001). GHF defined in this study showed higher sensitivity to the presence of carotid plaque than other definitions of GHF. CONCLUSIONS: GHF status was associated with risk of carotid plaque in individuals without history of CVD. Presence of subclinical carotid plaque was associated with risk of future CVD. Therefore, GHF based on creatinine could be a useful surrogate marker for surveillance of CVD in asymptomatic individuals.

Changes in abdominal fat depots after bariatric surgery are associated with improved metabolic profile.

BACKGROUND AND AIMS: Obesity associated with a change in the quantity and quality of fat depots. Using computed tomography (CT), we analyzed abdominal fat depots in patients with obesity after bariatric surgery according to their metabolic health status. METHODS AND RESULTS: We recruited 79 individuals with metabolically unhealthy obesity before bariatric surgery and compared them with age-sex matched healthy controls. The volume and fat attenuation index (FAI) of fat depots were measured using CT scans that were conducted prior to and a year after bariatric surgery. 'Metabolically healthy' was defined as having no hypertension, normal fasting glucose and a waist-to-hip ratio of <1.05 for men and <0.95 for women. Individuals who achieved a metabolic health status conversion (MHC) (n = 29, 37%)-from unhealthy to healthy-were younger (p < 0.001) as compared to individuals without MHC. Pre-surgery BMI and reduction of BMI did not differ between the two groups (p = 0.099, p = 0.5730). Bariatric surgery reduced the volume and increased the FAI of fat depots. Baseline lower abdominal periaortic adipose tissue (AT) volume (p = 0.014) and great percent reduction in renal sinus AT volume after surgery (p = 0.019) were associated with MHC after surgery. Increased intraperitoneal AT FAI (p = 0.031) was also associated with MHC. CONCLUSION: MHC was not associated with improvement in general obesity, based on indicators such as reduction of BMI after surgery. Weight reduction induced specific abdominal fat depot changes measured by CT are positively associated with MHC.

Factors Affecting Hospice Use Among Adolescents and Young Adult Cancer Patients.

Background/Objective: Compared to existing studies on end-of-life care of mid- to older-aged patients diagnosed with cancer, there is a paucity of research on adolescents and young adult (AYA) patients. Guided by the Anderson's Behavioral Model for Healthcare Utilization, this study examined predisposing/enabling/need factors associated with hospice referral/enrollment among AYA patients diagnosed with cancer. Methods: Data were drawn from medical records of AYA patients who died of cancer between January 2013 and December 2016 at three academic sites in the United States and were 15-39 years old at the time of death. Logistic regression was conducted (N = 224). Results: Findings showed that hospice referral was strongly associated with hospice enrollment (odds ratio [OR] = 69.68, p < 0.0001). White patients were more likely to be referred to hospice care than non-White patients; the effect was, however, significant only among patients with private insurance (OR = 3.44, p = 0.040). Patients with public insurance were more likely to be referred to hospice than those with private insurance; the effect was, however, significant only among non-White patients (OR = 5.66, p = 0.005). Among those not receiving cancer treatment in the last month of life (LML), patients with hematologic malignancies were less likely to be referred to hospice than those with solid tumors (OR = 0.19). Among patients with solid tumors, receiving cancer treatment in the LML lowered the odds of hospice referral (OR = 0.50, p = 0.043). Conclusion: Further research efforts are needed to investigate the role of race, insurance, cancer types, and treatments in hospice use among bigger samples of AYA patients diagnosed with cancer.

LCK-Mediated RIPK3 Activation Controls Double-Positive Thymocyte Proliferation and Restrains Thymic Lymphoma by Regulating the PP2A-ERK Axis.

Receptor-interacting protein kinase 3 (RIPK3) is the primary regulator of necroptotic cell death. RIPK3 expression is often silenced in various cancer cells, which suggests that it may have tumor suppressor properties. However, the exact mechanism by which RIPK3 negatively regulates cancer development and progression remains unclear. This report indicates that RIPK3 acts as a potent regulator of the homeostatic proliferation of CD4+ CD8+ double-positive (DP) thymocytes. Abnormal proliferation of RIPK3-deficient DP thymocytes occurs independently of the well-known role for RIPK3 in necroptosis (upstream of MLKL activation), and is associated with an incidental thymic mass, likely thymic hyperplasia. In addition, Ripk3-null mice develop increased thymic tumor formation accompanied by reduced host survival in the context of an N-ethyl-N-nitrosourea (ENU)-induced tumor model. Moreover, RIPK3 deficiency in p53-null mice promotes thymic lymphoma development via upregulated extracellular signal-regulated kinase (ERK) signaling, which correlates with markedly reduced survival rates. Mechanistically, lymphocyte-specific protein tyrosine kinase (LCK) activates RIPK3, which in turn leads to increases in the phosphatase activity of protein phosphatase 2 (PP2A), thereby suppressing hyper-activation of ERK in DP thymocytes. Overall, these findings suggest that a RIPK3-PP2A-ERK signaling axis regulates DP thymocyte homeostasis and may provide a potential therapeutic target to improve thymic lymphoma therapies.

Weight Change Alters the Small RNA Profile of Urinary Extracellular Vesicles in Obesity.

INTRODUCTION: Various kidney diseases reportedly show different urinary extracellular vesicle (EV) RNA profiles. Although obesity is one of the main causes of chronic kidney disease, the expression pattern of urinary EV RNA in obesity is uncertain. Our aim was to sequence the small RNA profiles of urinary EVs in obese patients before and after weight reduction and compare them to those of healthy volunteers (HVs). METHODS: We recruited age-sex-matched obese patients and HVs. The small RNA profiles of urinary EVs were analyzed using RNA sequencing. To evaluate the effect of weight reduction, small RNA profiles of urinary EVs 6 months after bariatric surgery were also analyzed. RESULTS: The proportion of urinary EVs transfer RNA and microRNA of obese patients differed from that of HVs. Obese patients showed differential expression of 1,343 small RNAs in urinary EVs compared to HVs (fold change ≥2 and p value <0.05). Among those, 61 small RNAs were upregulated in obese patients and downregulated after weight reduction, whereas 167 small RNAs were downregulated in obese patients and upregulated after weight reduction. RNA sequencing revealed the correlation between the specific urinary EV small RNAs and clinical parameters including body weight, low-density lipoprotein cholesterol, triglyceride, high-density lipoprotein cholesterol, serum glucose, estimated glomerular filtration rate, and albuminuria. CONCLUSION: Obese patients showed distinct urinary EV small RNA profiles compared to HVs. Weight reduction altered urinary EV small-RNA profiles in obese patients.

Abdominal periaortic and renal sinus fat attenuation indices measured on computed tomography are associated with metabolic syndrome.

OBJECTIVES: To investigate the association between abdominal periaortic (APA) and renal sinus (RS) fat attenuation index (FAI) measured on MDCT and metabolic syndrome in non-obese and obese individuals. METHODS: Visceral, subcutaneous, RS, and APA adipose tissue were measured in preoperative abdominal CT scans of individuals who underwent donor nephrectomy (n = 84) or bariatric surgery (n = 155). FAI was defined as the mean attenuation of measured fat volume. Participants were categorized into four groups: non-obese without metabolic syndrome (n = 64), non-obese with metabolic syndrome (n = 25), obese without metabolic syndrome (n = 21), and obese with metabolic syndrome (n = 129). The volume and FAI of each fat segment were compared among the groups. Receiver operator characteristics curve analysis was used to assess the association between the FAIs and metabolic syndrome. RESULTS: FAIs of all abdominal fat segments were significantly lower in the obese group than in the non-obese group (p < 0.001). RS, APA, and the visceral adipose tissue FAIs were significantly lower in participants with metabolic syndrome than in those without metabolic syndrome in the non-obese group (p < 0.001, p = 0.006, and p < 0.001, respectively). The area under the curve for predicting metabolic syndrome was significantly higher for APA FAI (0.790) than subcutaneous, visceral, and RS FAI in all groups (0.649, 0.647, and 0.655, respectively). CONCLUSION: Both metabolic syndrome and obesity were associated with lower RS and APA adipose tissue FAI, and APA FAI performed best for predicting metabolic syndrome. KEY POINTS: • The volume and FAI of RS, APA, and visceral adipose tissue showed opposite trends with regard to metabolic syndrome or obesity. • Both metabolic syndrome and obesity were associated with lower RS FAI and APA FAI. • APA FAI performed best for predicting metabolic syndrome among FAIs of abdominal fat segments.

Relationship between carbohydrate-to-fat intake ratio and the development of chronic kidney disease: A community-based prospective cohort study.

BACKGROUND & AIMS: It is well-known that high protein intake is associated with renal hyperfiltration and faster renal function decline, but the association of other macronutrients, carbohydrate and fat, with development of chronic kidney disease (CKD) is still inconclusive. Therefore, we aimed to examine the relationship between fat-to-carbohydrate intake ratio (F/C ratio) and incident CKD. METHODS: We included 9226 subjects from the Korean Genome and Epidemiology Study. The subjects were divided into two groups depending on 1 g protein intake per ideal body weight per day. Primary exposure was the F/C ratio defined as calorie intake of fat/calorie intake of fat and carbohydrate. The primary outcome was the development of CKD, which was defined as an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2 and/or proteinuria (≥1+). RESULTS: During a median follow-up duration of 11.4 years, 778 (8.4%) CKD events occurred. Subjects in the lowest F/C ratio tertile had faster eGFR decline rate than other tertiles. In multivariable Cox analysis, a significantly higher CKD risk was observed in the lowest tertile when protein intake > 1 g/kg/day (hazard ratio [HR] for T1 (<16.1%) vs. T3 (>21.5%), 1.38; 95% confidence interval [CI], 1.03-1.84; P = 0.031). In sensitivity analysis, subjects maintained low F/C ratio diet (<16.1%) during 4 years showed higher risk of subsequent CKD development than those maintained high F/C ratio diet (≥16.1%; HR, 1.70; 95% CI, 1.10-2.63; P = 0.018). In cubic spline analysis, CKD risk was sharply increased in F/C ratio <16.1%, but the risk was nearly constant in F/C ratio ≥16.1%. CONCLUSIONS: A diet with a low F/C ratio was associated with increased risk of CKD in the general population. Therefore, it is necessary to limit excessive high carbohydrate and low fat intake to prevent CKD development in this population.

Metformin inhibits chronic kidney disease-induced DNA damage and senescence of mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are promising source of cell-based regenerative therapy. In consideration of the risk of allosensitization, autologous MSC-based therapy is preferred over allogenic transplantation in patients with chronic kidney disease (CKD). However, it remains uncertain whether adequate cell functionality is maintained under uremic conditions. As chronic inflammation and oxidative stress in CKD may lead to the accumulation of senescent cells, we investigated cellular senescence of CKD MSCs and determined the effects of metformin on CKD-associated cellular senescence in bone marrow MSCs from sham-operated and subtotal nephrectomized mice and further explored in adipose tissue-derived MSCs from healthy kidney donors and patients with CKD. CKD MSCs showed reduced proliferation, accelerated senescence, and increased DNA damage as compared to control MSCs. These changes were significantly attenuated following metformin treatment. Lipopolysaccharide and transforming growth factor ß1-treated HK2 cells showed lower tubular expression of proinflammatory and fibrogenesis markers upon co-culture with metformin-treated CKD MSCs than with untreated CKD MSCs, suggestive of enhanced paracrine action of CKD MSCs mediated by metformin. In unilateral ureteral obstruction kidneys, metformin-treated CKD MSCs more effectively attenuated inflammation and fibrosis as compared to untreated CKD MSCs. Thus, metformin preconditioning may exhibit a therapeutic benefit by targeting accelerated senescence of CKD MSCs.

Validation of an international prediction model including the Oxford classification in Korean patients with IgA nephropathy.

BACKGROUND: Recently, a new international risk prediction model including the Oxford classification was published which was validated in a large multi-ethnic cohort. Therefore, we aimed to validate this risk prediction model in Korean patients with IgA nephropathy. METHODS: This retrospective cohort study was conducted with 545 patients who diagnosed IgA nephropathy with renal biopsy in three medical centers. The primary outcome was defined as a reduction in estimated glomerular filtration rate (eGFR) of >50% or incident end-stage renal disease (ESRD). Continuous net reclassification improvement (cNRI) and integrated discrimination improvement (IDI) were used to validate models. RESULTS: During the median 3.6 years of follow-up period, 53 (9.7%) renal events occurred. In multivariable Cox regression model, M1 (hazard ratio [HR], 2.22; 95% confidence interval [CI], 1.02-4.82; p = .043), T1 (HR, 2.98; 95% CI, 1.39-6.39; p = .005) and T2 (HR, 4.80; 95% CI, 2.06-11.18; p < .001) lesions were associated with increased risk of renal outcome. When applied the international prediction model, the area under curve (AUC) for 5-year risk of renal outcome was 0.69, which was lower than previous validation and internally derived models. Moreover, cNRI and IDI analyses showed that discrimination and reclassification performance of the international model was inferior to the internally derived models. CONCLUSION: The international risk prediction model for IgA nephropathy showed not as good performance in Korean patients as previous validation in other ethnic group. Further validation of risk prediction model is needed for Korean patients with IgA nephropathy.

Access Barrier in Rural Older Adults' Use of Pain Management and Palliative Care Services: A Systematic Review.

BACKGROUND: Pain and symptom management is critical in ensuring quality of life for chronically ill older adults. However, while pain management and palliative care have steadily expanded in recent years, many underserved populations, such as rural older adults, experience barriers in accessing such specialty services, in part due to transportation issues. The purpose of this systematic review is to examine the specific types of transportation-related barriers experienced by rural older adults in accessing pain and palliative care. METHODS: Studies were searched through the following 10 databases: Abstracts in Social Gerontology, Academic Search Premier, CINAHL, MEDLINE, PsycINFO, SocINDEX with Full Text, Cochrane Database of Systematic Reviews, Nursing & Allied Health Database, Sociological Abstracts, and PubMED. Studies were chosen for initial review if they were written in English, full text, included older adults in the sample, and examined pain/palliative care/hospice, rural areas, and transportation. A total of 174 abstracts were initially screened, 15 articles received full-text reviews and 8 met the inclusion criteria. RESULTS: Findings of the 8 studies identified transportation-related issues as major access barrier to pain and palliative care among rural older adults: specifically, lack of public transportation; lack of wheelchair accessible vehicles; lack of reliable drivers; high cost of transportation services; poor road conditions; and remoteness to the closest pain and palliative care service providers. CONCLUSION: Results suggest that rural older adults have unique transportation needs due to the urban-centric location of pain and palliative care services. Implications for practice, policy and research with older adults are discussed.

Educational intervention to improve palliative care knowledge among informal caregivers of cognitively impaired older adults.

OBJECTIVE: Lack of palliative care knowledge among caregivers may pose an access barrier for cognitively impaired older adults, who may benefit from the specialized care. Therefore, this study aims to examine the effectiveness of an educational intervention in improving palliative care knowledge among informal caregivers of cognitively impaired older adults. METHOD: Using a one-group, pre- and post-test intervention design, this study implemented an individual, face-to-face educational intervention with an informational brochure for 43 informal caregivers of chronically or seriously ill older adults (50+) with cognitive impairment, recruited from communities in West Alabama. Their level of knowledge about palliative care was assessed by the Palliative Care Knowledge Scale (PaCKS). The pre- and post-test scores were compared by the Wilcoxon signed-ranks test, and the racial subgroup (Whites vs. Blacks) comparison was made by the Mann-Whitney U test. RESULTS: There was a statistically significant difference between the pre- and post-test scores (z = 5.38, p < 0.001), indicating a statistically significant effect of the educational intervention in improving palliative care knowledge among participants. There was a significant difference (U = 143, p < 0.05) between Whites and Blacks in the pre-test, which, however, disappeared in the post-test (U = 173.50, p > 0.05), suggesting that the amount of increased PaCKS scores were significantly greater for Blacks (Mdn = 9.50) than for Whites (Mdn = 4.00, U = 130.50, p < 0.05). SIGNIFICANCE OF RESULTS: This study demonstrated that a one-time educational intervention can improve the level of palliative care knowledge among informal caregivers of chronically or seriously ill older adults with cognitive impairment, particularly among Black caregivers. Therefore, further educational efforts can be made to promote palliative care knowledge and reduce racial disparities in palliative care knowledge and its use.

Effect of bariatric surgery on circulating and urinary mitochondrial DNA copy numbers in obesity with or without diabetes.

INTRODUCTION: Recent studies have suggested that extracellular circulating and urinary mitochondrial DNA (mtDNA) are associated with mitochondrial dysfunction in obesity and type 2 diabetes mellitus (T2DM). However, the changes to cell-free serum and urinary mtDNA after bariatric surgery in patients with obesity with T2DM have not been investigated to date. RESEARCH DESIGN AND METHODS: We prospectively recruited patients with obesity (n=18), and with obesity and T2DM (n=14) who underwent bariatric surgery, along with healthy volunteers (HV) as a control group (n=22). Serum and urinary mitochondrial nicotinamide adenine dinucleotide dehydrogenase subunit-1 (mtND-1) and cytochrome-c oxidase 3 (mtCOX-3) copy numbers were measured using quantitative PCR (qPCR). The mtDNA copy numbers of patients with obesity (with and without T2DM) were followed up 6 months after surgery. RESULTS: The copy numbers of urinary mtND-1 and mtCOX-3 in patients with obesity, with or without T2DM, were higher than those in the HVs. Moreover, urinary mtCOX-3 copy number increased in patients with obesity with T2DM compared with patients with obesity without T2DM (p=0.018). Meanwhile, serum mtCOX-3 copy numbers in HV were higher in both obesity patient groups (p=0.040). Bariatric surgery reduced urinary mtND-1 and mtCOX-3 copy numbers, as well as serum mtCOX-3 copy numbers only in patients with obesity with T2DM. CONCLUSION: These results suggest that T2DM induces greater kidney mitochondrial dysfunction in patients with obesity, which can be effectively restored with bariatric surgery.

Sex-Biased Molecular Signature for Overall Survival of Liver Cancer Patients.

Sex/gender disparity has been shown in the incidence and prognosis of many types of diseases, probably due to differences in genes, physiological conditions such as hormones, and lifestyle between the sexes. The mortality and survival rates of many cancers, especially liver cancer, differ between men and women. Due to the pronounced sex/gender disparity, considering sex/ gender may be necessary for the diagnosis and treatment of liver cancer. By analyzing research articles through a PubMed literature search, the present review identified 12 genes which showed practical relevance to cancer and sex disparities. Among the 12 sex-specific genes, 7 genes (BAP1, CTNNB1, FOXA1, GSTO1, GSTP1, IL6, and SRPK1) showed sex-biased function in liver cancer. Here we summarized previous findings of cancer molecular signature including our own analysis, and showed that sexbiased molecular signature CTNNB1High, IL6High, RHOAHigh and GLIPR1Low may serve as a female-specific index for prediction and evaluation of OS in liver cancer patients. This review suggests a potential implication of sex-biased molecular signature in liver cancer, providing a useful information on diagnosis and prediction of disease progression based on gender.

TRIM24-RIP3 axis perturbation accelerates osteoarthritis pathogenesis.

OBJECTIVES: Recently, necroptosis has attracted increasing attention in arthritis research; however, it remains unclear whether its regulation is involved in osteoarthritis (OA) pathogenesis. Since receptor-interacting protein kinase-3 (RIP3) plays a pivotal role in necroptosis and its dysregulation is involved in various pathological processes, we investigated the role of the RIP3 axis in OA pathogenesis. METHODS: Experimental OA was induced in wild-type or Rip3 knockout mice by surgery to destabilise the medial meniscus (DMM) or the intra-articular injection of adenovirus carrying a target gene (Ad-Rip3 and Ad-Trim24 shRNA). RIP3 expression was examined in OA cartilage from human patients; Trim24, a negative regulator of RIP3, was identified by microarray and in silico analysis. Connectivity map (CMap) and in silico binding approaches were used to identify RIP3 inhibitors and to examine their direct regulation of RIP3 activation in OA pathogenesis. RESULTS: RIP3 expression was markedly higher in damaged cartilage from patients with OA than in undamaged cartilage. In the mouse model, adenoviral RIP3 overexpression accelerated cartilage disruption, whereas Rip3 depletion reduced DMM-induced OA pathogenesis. Additionally, TRIM24 knockdown upregulated RIP3 expression; its downregulation promoted OA pathogenesis in knee joint tissues. The CMap approach and in silico binding assay identified AZ-628 as a potent RIP3 inhibitor and demonstrated that it abolished RIP3-mediated OA pathogenesis by inhibiting RIP3 kinase activity. CONCLUSIONS: TRIM24-RIP3 axis perturbation promotes OA chronicity by activating RIP3 kinase, suggesting that the therapeutic manipulation of this pathway could provide new avenues for treating OA.

microRNA in Extracellular Vesicles Released by Damaged Podocytes Promote Apoptosis of Renal Tubular Epithelial Cells.

Tubular injury and fibrosis are associated with progressive kidney dysfunction in advanced glomerular disease. Glomerulotubular crosstalk is thought to contribute to tubular injury. microRNAs (miRNAs) in extracellular vesicles (EVs) can modulate distant cells. We hypothesized that miRNAs in EVs derived from injured podocytes lead to tubular epithelial cell damage. As proof of this concept, tubular epithelial (HK2) cells were cultured with exosomes from puromycin-treated or healthy human podocytes, and damage was assessed. Sequencing analysis revealed the miRNA repertoire of podocyte EVs. RNA sequencing identified 63 upregulated miRNAs in EVs from puromycin-treated podocytes. Among them, five miRNAs (miR-149, -424, -542, -582, and -874) were selected as candidates for inducing tubular apoptosis according to a literature-based search. To validate the effect of the miRNAs, HK2 cells were treated with miRNA mimics. EVs from injured podocytes induced apoptosis and p38 phosphorylation of HK2 cells. The miRNA-424 and 149 mimics led to apoptosis of HK2 cells. These results show that miRNAs in EVs from injured podocytes lead to damage to tubular epithelial cells, which may contribute to the development of tubular injury in glomerular disease.

Melatonin suppresses senescence-derived mitochondrial dysfunction in mesenchymal stem cells via the HSPA1L-mitophagy pathway.

Mesenchymal stem cells (MSCs) are a popular cell source for stem cell-based therapy. However, continuous ex vivo expansion to acquire large amounts of MSCs for clinical study induces replicative senescence, causing decreased therapeutic efficacy in MSCs. To address this issue, we investigated the effect of melatonin on replicative senescence in MSCs. In senescent MSCs (late passage), replicative senescence decreased mitophagy by inhibiting mitofission, resulting in the augmentation of mitochondrial dysfunction. Treatment with melatonin rescued replicative senescence by enhancing mitophagy and mitochondrial function through upregulation of heat shock 70 kDa protein 1L (HSPA1L). More specifically, we found that melatonin-induced HSPA1L binds to cellular prion protein (PrPC ), resulting in the recruitment of PrPC into the mitochondria. The HSPA1L-PrPC complex then binds to COX4IA, which is a mitochondrial complex IV protein, leading to an increase in mitochondrial membrane potential and anti-oxidant enzyme activity. These protective effects were blocked by knockdown of HSPA1L. In a murine hindlimb ischemia model, melatonin-treated senescent MSCs enhanced functional recovery by increasing blood flow perfusion, limb salvage, and neovascularization. This study, for the first time, suggests that melatonin protects MSCs against replicative senescence during ex vivo expansion for clinical application via mitochondrial quality control.