Application of visual transformer in renal image analysis.

Deep Self-Attention Network (Transformer) is an encoder-decoder architectural model that excels in establishing long-distance dependencies and is first applied in natural language processing. Due to its complementary nature with the inductive bias of convolutional neural network (CNN), Transformer has been gradually applied to medical image processing, including kidney image processing. It has become a hot research topic in recent years. To further explore new ideas and directions in the field of renal image processing, this paper outlines the characteristics of the Transformer network model and summarizes the application of the Transformer-based model in renal image segmentation, classification, detection, electronic medical records, and decision-making systems, and compared with CNN-based renal image processing algorithm, analyzing the advantages and disadvantages of this technique in renal image processing. In addition, this paper gives an outlook on the development trend of Transformer in renal image processing, which provides a valuable reference for a lot of renal image analysis.

The role of N-methyladenosine modification in acute and chronic kidney diseases.

N6-methyladenosine (m6A) modification is a kind of RNA modification in which methylation occurs at the sixth N position in adenosine in RNA, which can occur in various RNAs such as mRNAs, lncRNAs and miRNAs. This is one of the most prominent and frequent posttranscriptional modifications within organisms and has been shown to function dynamically and reversibly in a variety of ways, including splicing, export, attenuation and translation initiation efficiency to regulate RNA expression. There are three main enzymes associated with m6A modification: writers, readers and erasers. Increasing evidence has shown that m6A modification is associated with the onset and development of kidney disease. In this article, we address the important physiological and pathological roles of m6A modification in kidney diseases (uremia, ischemia-reperfusion kidney injury, drug-induced kidney injury, and diabetic nephropathy) and its molecular mechanisms to provide reference for the diagnosis and clinical management of kidney diseases.

Single-cell RNA sequencing for the study of kidney disease.

The kidney is an important organ for maintaining normal metabolism and stabilising the internal environment, in which, the heterogeneity of cell types has hindered the progress in understanding the mechanisms underlying kidney disease. In recent years the application of single-cell RNA sequencing (scRNA-seq) in nephrology has developed rapidly. In this review, we summarized the technical platform related to scRNA-seq and the role of this technology in investigating the onset and development of kidney diseases, starting from several common kidney diseases (mainly including lupus nephritis, renal cell carcinoma, diabetic nephropathy and acute kidney injury), and provide a reference for the application of scRNA-seq in the study of kidney disease diagnosis, treatment and prognosis.

DNA hypermethylation-induced miR-182 silence targets BCL2 and HOXA9 to facilitate the self-renewal of leukemia stem cell, accelerate acute myeloid leukemia progression, and determine the sensitivity of BCL2 inhibitor venetoclax.

Rationale: microRNAs (miRNAs) are frequently deregulated and play important roles in the pathogenesis and progression of acute myeloid leukemia (AML). miR-182 functions as an onco-miRNA or tumor suppressor miRNA in the context of different cancers. However, whether miR-182 affects the self-renewal of leukemia stem cells (LSCs) and normal hematopoietic stem progenitor cells (HSPCs) is unknown. Methods: Bisulfite sequencing was used to analyze the methylation status at pri-miR-182 promoter. Lineage-negative HSPCs were isolated from miR-182 knockout (182KO) and wild-type (182WT) mice to construct MLL-AF9-transformed AML model. The effects of miR-182 depletion on the overall survival and function of LSC were analyzed in this mouse model in vivo. Results: miR-182-5p (miR-182) expression was lower in AML blasts than normal controls (NCs) with hypermethylation observed at putative pri-miR-182 promoter in AML blasts but unmethylation in NCs. Overexpression of miR-182 inhibited proliferation, reduced colony formation, and induced apoptosis in leukemic cells. In addition, depletion of miR-182 accelerated the development and shortened the overall survival (OS) in MLL-AF9-transformed murine AML through increasing LSC frequency and self-renewal ability. Consistently, overexpression of miR-182 attenuated AML development and extended the OS in the murine AML model. Most importantly, miR-182 was likely dispensable for normal hematopoiesis. Mechanistically, we identified BCL2 and HOXA9 as two key targets of miR-182 in this context. Most importantly, AML patients with miR-182 unmethylation had high expression of miR-182 followed by low protein expression of BCL2 and resistance to BCL2 inhibitor venetoclax (Ven) in vitro. Conclusions: Our results suggest that miR-182 is a potential therapeutic target for AML patients through attenuating the self-renewal of LSC but not HSPC. miR-182 promoter methylation could determine the sensitivity of Ven treatment and provide a potential biomarker for it.

Fibroblast growth factor 21 attenuates salt-sensitive hypertension-induced nephropathy through anti-inflammation and anti-oxidation mechanism.

BACKGROUND: Patients with salt-sensitive hypertension are often accompanied with severe renal damage and accelerate to end-stage renal disease, which currently lacks effective treatment. Fibroblast growth factor 21 (FGF21) has been shown to suppress nephropathy in both type 1 and type 2 diabetes mice. Here, we aimed to investigate the therapeutic effect of FGF21 in salt-sensitive hypertension-induced nephropathy. METHODS: Changes of FGF21 expression in deoxycorticosterone acetate (DOCA)-salt-induced hypertensive mice were detected. The influence of FGF21 knockout in mice on DOCA-salt-induced nephropathy were determined. Recombinant human FGF21 (rhFGF21) was intraperitoneally injected into DOCA-salt-induced nephropathy mice, and then the inflammatory factors, oxidative stress levels and kidney injury-related indicators were observed. In vitro, human renal tubular epithelial cells (HK-2) were challenged by palmitate acid (PA) with or without FGF21, and then changes in inflammation and oxidative stress indicators were tested. RESULTS: We observed significant elevation in circulating levels and renal expression of FGF21 in DOCA-salt-induced hypertensive mice. We found that deletion of FGF21 in mice aggravated DOCA-salt-induced nephropathy. Supplementation with rhFGF21 reversed DOCA-salt-induced kidney injury. Mechanically, rhFGF21 induced AMPK activation in DOCA-salt-treated mice and PA-stimulated HK-2 cells, which inhibited NF-κB-regulated inflammation and Nrf2-mediated oxidative stress and thus, is important for rhFGF21 protection against DOCA-salt-induced nephropathy. CONCLUSION: These findings indicated that rhFGF21 could be a promising pharmacological strategy for the treatment of salt-sensitive hypertension-induced nephropathy.

Islet transplantation ameliorates diabetes-induced testicular interstitial fibrosis and is associated with inhibition of TGF-ß1/Smad2 pathway in a rat model of type 1 diabetes.

Islet transplantation (IT) is considered the most effective endocrine replacement therapy for diabetes mellitus (DM). Studies have demonstrated that IT can repair testicular structural injury caused by inflammatory and oxidative stress in a diabetic rat model. However, highly effective exogenous antioxidant and anti-inflammatory drugs can achieve this effect. Testicular interstitial fibrosis caused by long-term hyperglycemia is however difficult to reverse or recover. Thus far, there are no effective drugs that prevent or relieve testicular interstitial fibrosis. Therefore, it is necessary to explore the potential benefit of IT on testicular interstitial fibrosis induced by DM and its underlying molecular mechanisms. In the present study, Wistar rats were used to establish a DM model by intraperitoneal injection of streptozotocin. The diabetic models then underwent IT or received insulin treatment after 12 weeks. IT was more effective than insulin treatment in ameliorating diabetic-induced testicular interstitial fibrosis, Leydig cells apoptosis, testosterone deficiency and poor sperm motility. IT and insulin treatment both significantly inhibited the upregulation of TGF-ß1 and phosphorylated Smad2 in DM, with IT being more effective than insulin. The present study's findings proved that IT effectively protects diabetic-induced testicular interstitial fibrosis probably by inhibiting the TGF-ß1/Smad2 signaling pathway, which offers hope in male patients with DM complicating with testicular interstitial fibrosis.

Homocysteine aggravates DNA damage by impairing the FA/Brca1 Pathway in NE4C murine neural stem cells.

There is existing evidence that elevated homocysteine (Hcy) levels are risk factors for some neurodegenerative disorders. The pathogenesis of neurological diseases could be contributed to excessive cell dysfunction and death caused by defective DNA damage response (DDR) and accumulated DNA damage. Hcy is a neurotoxic amino acid and acts as a DNA damage inducer. However, it is not clear whether Hcy participates in the DDR. To investigate the effects of Hcy on DNA damage and the DDR, we employed mitomycin C (MMC) to cause DNA damage in NE4C murine neural stem cells (NSCs). Compared to treatment with MMC alone, we found that co-treatment with MMC and Hcy worsened DNA damage and increased death in NE4C cells. Intriguingly, in this DNA damage model mimicked by MMC, immunoblotting results showed that the monoubiquitination levels of Fanconi anemia complementation group I (Fanci) and Fanconi anemia complementation group D2 (Fancd2) were decreased to about 60.3% and 55.7% by supplementing cell culture medium with Hcy, indicating Hcy inactivates the function of Fanci and Fancd2 in DNA damage conditions. Given Breast Cancer 1 (BRCA1) is an important downstream of FANCD2, we next detected the interaction between Fancd2 and Brca1 in NE4C cells. Compared to treatment with MMC alone, the Fancd2-Brca1 interaction and the amount of Brca1 on chromatin were decreased when cells were co-exposed to MMC and Hcy, suggesting Hcy could impair the Fanconi anemia (FA)/Brca1 pathway. Taken together, our study demonstrates that Hcy may enhance cell death, which contributes to the accumulation of DNA damage and promotion of hypersensitivity to cytotoxicity by impairing the FA/Brca1 pathway in murine NSCs in the presence of DNA damage.

Low-Dose Vitamin D Protects Hyperoxia-Induced Bronchopulmonary Dysplasia by Inhibiting Neutrophil Extracellular Traps.

Background and Objective: As bronchopulmonary dysplasia (BPD) can lead to considerable mortality and morbidity, this disease is the focus of attention in neonatology. Vitamin D (VD), which has anti-inflammatory properties and promotes lung growth, may have a therapeutic effect on BPD. The overexpression of neutrophil extracellular traps (NETs) has been demonstrated to be involved in the pathogenesis of BPD in our previous study. This study aimed to elucidate the effect of VD on BPD and the role of NETs in this process. Methods: Newborn rats were exposed to 90% oxygen continuously for 7 days to mimic BPD, and rats under hyperoxia were injected with 1,25(OH)2D3 at different doses (0.5 ng/g, 3 ng/g). Alveolarization, pulmonary vascular development, inflammatory cytokines and NETs were assessed. Results: Hyperoxia increased mortality, decreased body weight, impaired alveolarization with a decrease in radial alveolar count (RAC) and an increase in mean linear intercept (MLI), and impaired vascular development with low vascular endothelial growth factor (VEGF) expression. Meanwhile, hyperoxia enhanced expression of the proinflammatory factors TNF-α, IL-1ß, and IL-6, and elevated NETs in lung tissues and plasma. Low-dose VD (0.5 ng/g) administration increased the survival rate, attenuated developmental retardation, improved alveolarization, and pulmonary vascular development in hyperoxia-induced BPD, and reduced the expression of proinflammatory factors and NETs. However, high-dose VD (3 ng/g) treatment did not attenuate lung injury or NETs significantly, and even led to more severe developmental retardation and a higher mortality rate. Conclusions: Low-dose VD increased the survival rate, attenuated developmental retardation, and improved alveolarization and pulmonary vascularization arrest in hyperoxia-induced BPD partially by inhibiting NETs.

CircNr1h4 regulates the pathological process of renal injury in salt-sensitive hypertensive mice by targeting miR-155-5p.

Circular RNAs are a class of widespread and diverse endogenous RNAs that may regulate gene expression in various diseases, but their regulation and function in hypertensive renal injury remain unclear. In this study, we generated ribosomal-depleted RNA sequencing data from normal mouse kidneys and from injured mouse kidneys induced by deoxycorticosterone acetate-salt hypertension and identified at least 4900 circRNA candidates. A total of 124 of these circRNAs were differentially expressed between the normal and injured kidneys. Furthermore, we characterized one abundant circRNA, termed circNr1h4, which is derived from the Nr1h4 gene and significantly down-regulated in the injured kidneys. RNA sequencing data and qPCR analysis also showed many microRNAs and mRNAs, including miR-155-5p and fatty acid reductase 1 (Far1), were differentially expressed between the normal and injured kidney and related to circNr1h4. In vitro, the silencing of circNr1h4 or overexpression of miR-155-5p significantly decreased Far1 levels and increased reactive oxygen species. Mechanistic investigations indicated that circNr1h4 acts as a competing endogenous RNA for miR-155-5p, leading to regulation of its target gene Far1. Our study provides novel insight into the molecular mechanisms underlying kidney injury in hypertension, which will be required to develop therapeutic strategies of targeting circRNAs for hypertensive kidney injury.

Pex11a deficiency causes dyslipidaemia and obesity in mice.

Peroxisomes play a central role in lipid metabolism. We previously demonstrated that Pex11a deficiency impairs peroxisome abundance and fatty acid ß-oxidation and results in hepatic triglyceride accumulation. The role of Pex11a in dyslipidaemia and obesity is investigated here with Pex11a knockout mice (Pex11a-/- ). Metabolic phenotypes including tissue weight, glucose tolerance, insulin sensitivity, cholesterol levels, fatty acid profile, oxygen consumption, physical activity were assessed in wild-type (WT) and Pex11a-/- fed with a high-fat diet. Molecular changes and peroxisome abundance in adipose tissue were evaluated through qRT-PCR, Western blotting, and Immunofluorescence. Pex11a-/- showed increased fat mass, decreased skeletal muscle, higher cholesterol levels, and more severely impaired glucose and insulin tolerance. Pex11a-/- consumed less oxygen, indicating a decrease in fatty acid oxidation, which is consistent with the accumulation of very long- and long-chain fatty acids. Adipose palmitic acid (C16:0) levels were elevated in Pex11a-/- , which may be because of dramatically increased fatty acid synthase mRNA and protein levels. Furthermore, Pex11a deficiency increased ventricle size and macrophage infiltration, which are related to the reduced physical activity. These data demonstrate that Pex11a deficiency impairs physical activity and energy expenditure, decreases fatty acid ß-oxidation, increases de novo lipogenesis and results in dyslipidaemia and obesity.

Urinary miR-21 as a potential biomarker of hypertensive kidney injury and fibrosis.

Kidney biopsy is considered the golden criterion for diagnosing the etiology of kidney disease but accompanied by non-negligible complications. We explored the possibility of using urinary microRNA (miRNA) as a non-invasive biomarker for hypertensive kidney injury. We assessed differential miRNA expressions in the kidneys and urine of hypertensive mice with kidney injury induced by deoxycorticosterone acetate (DOCA)-salt compared to the controls. DOCA-salt treatment significantly increased renal tubular lesions from day 2 and mRNA expression of fibrosis-related genes from day 4 compared to the controls, respectively. Urinary albumin and N-acetyl-beta-D-glucosaminidase was significantly increased on day 8 compared to the controls. Array results showed that 20 out of 585 miRNAs were highly expressed in the kidneys and significantly increased on day 8 compared to the controls, including miR-21, miR-146b, miR-155 and miR-132, which were confirmed by real-time polymerase chain reaction and were significantly higher from day 4. The miR-21/creatinine in the urine from day 4 was significantly higher than that of the controls and was detected earlier than urinary albumin. In conclusion, we have identified urinary miR-21 that correlates with histopathological lesions and functional markers of kidney damage to facilitate a potential noninvasive detection for hypertensive kidney injury.

miRNA Profiles of Tubular Cells: Diagnosis of Kidney Injury.

MicroRNAs (miRNAs) are small noncoding RNAs of 18-23 nucleotides that regulate gene expression. Recently, plasma miRNAs have been investigated as biomarkers for various physiological and pathological conditions. The present study details the conserved miRNA expression profiles of tubular tissues, and discusses whether they could be used to distinguish between proximal tubule injury, diagnose acute kidney injury (AKI), and the early-stage renal tubular dysfunction. miRNA expression was assessed with miRNA array and real-time reverse transcription polymerase chain reaction using the TaqMan system. The expression profiles of miR-200a/b/c, miR-145, miR-192, miR-194, miR-216a/b, miR-217, and miR-449a in human and rat tubular tissues such as the kidneys, lung, small intestine, and various exocrine glands were adequate for discriminating tubular tissues. In the kidney, miR-192 and miR-194 were highly expressed, whereas miR-145 and miR-449a were absent. miR-145 and miR-449a were relatively specifically expressed in small intestine and lung, respectively. Therefore, the combined levels of miR-200a/b/c, miR-192, and miR-194 in plasma were very useful in diagnosing AKI induced by contact freezing in mice. Moreover, urinary miR-200a levels were useful for the diagnosis of renal tubular dysfunction in Dahl salt-sensitive rat with high salt administration. Our results indicate that miRNA expression profiles are useful as biomarkers for identification of various kidney injuries.

Induction of peroxisomes by butyrate-producing probiotics.

We previously found that peroxisomal biogenesis factor 11a (Pex11a) deficiency is associated with a reduction in peroxisome abundance and impaired fatty acid metabolism in hepatocytes, and results in steatosis. In the present study, we investigated whether butyrate induces Pex11a expression and peroxisome proliferation, and studied its effect on lipid metabolism. C57BL/6 mice fed standard chow or a high-fat diet (HFD) were treated with tributyrin, 4-phelybutyrate acid (4-PBA), or the butyrate-producing probiotics (Clostridium butyricum MIYAIRI 588 [CBM]) plus inulin (dietary fiber), and the body weight, white adipose tissue, serum triglycerides, mRNA expression, and peroxisome abundance were evaluated. Tributyrin or 4-PBA treatment significantly decreased body weight and increased hepatic mRNA expression of peroxisome proliferator-activated receptor-α (PPARα) and Pex11a. In addition, 4-PBA treatment increased peroxisome abundance and the expression of genes involved in peroxisomal fatty acid ß-oxidation (acyl-coenzyme A oxidase 1 and hydroxysteroid [17-beta] dehydrogenase 4). CBM and inulin administration reduced adipose tissue mass and serum triglycerides, induced Pex11a, acyl-coenzyme A oxidase 1, and hydroxysteroid (17-beta) dehydrogenase 4 genes, and increased peroxisome abundance in mice fed standard chow or an HFD. In conclusion, elevation of butyrate availability (directly through administration of butyrate or indirectly via administration of butyrate-producing probiotics plus fiber) induces PPARα and Pex11a and the genes involved in peroxisomal fatty acid ß-oxidation, increases peroxisome abundance, and improves lipid metabolism. These results may provide a new therapeutic strategy against hyperlipidemia and obesity.

Pex11a deficiency is associated with a reduced abundance of functional peroxisomes and aggravated renal interstitial lesions.

Although proteinuria is known to be associated with the deterioration of chronic kidney disease, the molecular basis of this mechanism is not fully understood. We previously found that Pex11a deficiency was associated with a reduction of functional peroxisomes and impaired fatty acid metabolism in hepatocytes and resulted in steatosis. Proximal tubule cells are rich in peroxisomes. We assessed whether Pex11a deficiency might result in the derangement of peroxisome systems in proximal tubule cells and the aggravation of tubulointerstitial lesions in chronic kidney disease. Histological analyses showed that the number of functional peroxisomes in proximal tubule cells was reduced in Pex11a knockout (Pex11a(-/-)) mice. To clarify whether a decrease in the number of tubular peroxisomes might aggravate interstitial lesions, we assessed 2 models in which proximal tubule cells are overloaded with fatty acids (ie, deoxycorticosterone acetate and salt hypertension and the overload of fatty acid-bound albumin). Deoxycorticosterone acetate -salt-treated Pex11a(-/-) mice exhibited greater interstitial lesions than deoxycorticosterone acetate-salt-treated wild-type mice in terms of tubular lipid accumulation, blood pressure, urinary albumin, urinary N-acetyl-ß-d-glucosaminidase, urinary 8-iso-prostane, and the histological evaluation of fibrosis and inflammation. An overload of fatty acid-bound albumin also resulted in more severe tubulointerstitial lesions in Pex11a(-/-) mice than in wild-type mice. Fenofibrate, a peroxisome proliferator-activated receptor-α agonist, restored the abundance of peroxisomes and reduced the tubulointerstitial lesions induced by deoxycorticosterone acetate-salt hypertension. In conclusion, our results indicate that proximal tubule peroxisomes play an important role in proteinuria-induced interstitial lesions. The activation of tubular peroxisomes might be an excellent therapeutic strategy against chronic kidney disease.

A novel biomarker for acute kidney injury using TaqMan-based unmethylated DNA-specific polymerase chain reaction.

There has been increasing interest in the use of circulating DNA as biomarkers for various tissue injuries, cancers, and fetal conditions. DNA methylation is a well-characterized mechanism underlying the epigenetic regulation of gene expression, and many diagnostic tests based on DNA methylation patterns have been developed. We developed a novel TaqMan-based assay for the detection of acute kidney injury using a hypomethylated promoter region of Slc22a12, a urate transporter specifically expressed in proximal tubular cells. Bisulfite sequencing analysis confirmed that the CpG islands in the promoter region of mouse Slc22a12 were preferentially hypomethylated in the kidney cortex. TaqMan minor groove binder (MGB) probes reliably discriminated the DNA fragments corresponding to the unmethylated and methylated promoter regions of Slc22a12. Plasma levels of unmethylated DNA corresponding to the Slc22a12 promoter region were undetectable at baseline and were significantly elevated after acute kidney cortex necrosis. This study showed the usefulness of the TaqMan system in discriminating methylated and unmethylated DNA fragments, and the similar strategy can be applied for establishing biomarkers for various cellular injuries or pathological conditions.

MiR-216a and miR-216b as markers for acute phased pancreatic injury.

MicroRNAs (miRNAs) are endogenous small RNAs (length, 18-ss23 nucleotides) that regulate gene expression. Recently, plasma miRNAs have been investigated as biomarkers for various diseases. In the present study, we explored cell- or tissue-specific miRNAs and assessed the applicability of miRNA profiling for identifying biomarkers of tissue injuries. miRNA analyses in various human and rat tissues identified several candidate miRNAs with possible tissue-specific expression, some of which have already been reported. In the present study, we focused on pancreas-specific miRNAs, miR-216a and miR-216b. Laser microdissection revealed that miR-216a and 216b were predominantly expressed in acinar cells of the pancreas as compared to Langerhans' islet. Plasma concentrations of miR-216a and miR-216b considerably increased in a rat model of L-arginineinduced acute pancreatitis. The current results have confirmed that miRNA expression profiling in various cells is useful for providing biomarkers for cell- or tissue-specific injuries.

MicroRNA 210 as a biomarker for congestive heart failure.

MicroRNAs (miRNAs) are endogenous small RNAs that are 18-23 nucleotides long. Recently, plasma miRNAs were reported to be sensitive and specific biomarkers of various pathological conditions. In the present study, we focused on miR-210, which is known to be induced by hypoxia and might therefore be an excellent biomarker for congestive heart failure. Plasma miR-210 levels and expression levels in mononuclear cells and skeletal muscles were elevated in Dahl salt-sensitive rats with heart failure. We also assessed miR-210 expression in patients with heart failure. The miR-210 expression levels in the mononuclear cells of patients with NYHA III and IV heart failure according to the New York Heart Association (NYHA) functional classification system were significantly higher than those with NYHA II heart failure and controls. Although no significant correlation was observed between plasma brain natriuretic peptide (BNP) and plasma miR-210 levels in patients with NYHA II heart failure, patients with an improved BNP profile at the subsequent hospital visit were classified in a subgroup of patients with low plasma miR-210 levels. Plasma miR-210 levels may reflect a mismatch between the pump function of the heart and oxygen demand in the peripheral tissues, and be a new biomarker for chronic heart failure in addition to plasma BNP concentrations.

Classification of various muscular tissues using miRNA profiling.

MicroRNAs (miRNAs) are endogenous small RNAs of 18-23 nucleotides that regulate gene expression. Recently, plasma miRNAs have been investigated as biomarkers for various diseases. In the present study, we explored whether miRNA expression profiling of various muscle cells may be useful for the diagnosis of various diseases involving muscle necrosis. miRNA expression profiling was assessed by miRNA array and real-time reverse-transcriptase polymerase chain reaction by using a reverse primer of a stem loop structure. Profiling of various muscle cells of mouse, including cardiac muscles, skeletal muscles, and vascular and visceral smooth muscles, indicated that profiling of miR-1, miR-133a, miR-133b, miR-145, miR-206, miR-208a, miR-208b, and miR499 were adequate to discriminate muscle cells. miR-145 was remarkably highly expressed in smooth muscles. miR-208a and miR-499 were highly expressed in cardiomyocytes. miR-133a was highly expressed in fast-twitch skeletal muscles. miR-206 and miR-208b were expressed in the slow-twitch skeletal muscles, and they can likely discriminate fast- and slow-twitch types of skeletal muscle cells. We observed that brown fat adipose cells had an miRNA expression profile very similar to those of skeletal muscle cells in the mouse. Plasma concentrations of miR-133a and miR-145 were extremely useful in diagnosing skeletal muscle necrosis in a mouse model of Duchenne muscular dystrophy and colon smooth muscle necrosis in a rat ischemic colitis model, respectively. In the present study, we investigated the miRNA expression profiles of various muscular tissues. Our results suggest that expression profiling would be useful for the diagnosis of various diseases such as muscular necrosis.

Renoprotective mechanisms of pirfenidone in hypertension-induced renal injury: through anti-fibrotic and anti-oxidative stress pathways.

Pirfenidone (PFD) is a novel anti-fibrotic agent that targets TGFß. However, the mechanisms underlying its renoprotective properties in hypertension-induced renal injury are poorly understood. We investigated the renoprotective properties of PFD and clarified its renoprotective mechanisms in a rat hypertension-induced renal injury model. Dahl salt-sensitive rats were fed a high-salt diet with or without 1% PFD for 6 weeks. During the administration period, we examined the effects of PFD on blood pressure and renal function. After the administration, the protein levels of renal TGFß, Smad2/3, TNFα, MMP9, TIMP1, and catalase were examined. In addition, total serum antioxidant activity was measured. Compared to untreated rats, PFD treatment significantly attenuated blood pressure and proteinuria. Histological study showed that PFD treatment improved renal fibrosis. PFD may exert its anti-fibrotic effects via the downregulation of TGFß-Smad2/3 signaling, improvement of MMP9/TIMP1 balance, and suppression of fibroblast proliferation. PFD treatment also increased catalase expression and total serum antioxidant activity. In contrast, PFD treatment did not affect the expression of TNFα protein, macrophage or T-cell infiltration, or plasma interleukin 1ß levels. PFD prevents renal injury via its anti-fibrotic and anti-oxidative stress mechanisms. Clarifying the renoprotective mechanisms of PFD will help improve treatment for chronic renal diseases.

Pex11α deficiency impairs peroxisome elongation and division and contributes to nonalcoholic fatty liver in mice.

Hepatic triglyceride (TG) accumulation is considered to be a prerequisite for developing nonalcoholic fatty liver (NAFL). Peroxisomes have many important functions in lipid metabolism, including fatty acid ß-oxidization. However, the pathogenic link between NAFL and peroxisome biogenesis remains unclear. To examine the molecular and physiological functions of the Pex11α gene, we disrupted this gene in mice. Body weights and hepatic TG concentrations in Pex11α(-/-) mice were significantly higher than those in wild-type (WT) mice fed a normal or a high-fat diet. Hepatic TG concentrations in fasted Pex11α(-/-) mice were significantly higher than those in fasted WT mice. Plasma TG levels increased at lower rates in Pex11α(-/-) mice than in WT mice after treatment with the lipoprotein lipase inhibitor tyloxapol. The number of peroxisomes was lower in the livers of Pex11α(-/-) mice than in those of WT mice. Ultrastructural analysis showed that small and regular spherically shaped peroxisomes were more prevalent in Pex11α(-/-) mice fed normal chow supplemented without or with fenofibrate. We observed a significantly higher ratio of empty peroxisomes containing only PMP70, a peroxisome membrane protein, but not catalase, a peroxisome matrix protein, in Pex11α(-/-) mice. The mRNA expression levels of peroxisomal fatty acid oxidation-related genes (ATP-binding cassette, subfamily D, member 2, and acyl-CoA thioesterase 3) were significantly higher in WT mice than those in Pex11α(-/-) mice under fed conditions. Our results demonstrate that Pex11α deficiency impairs peroxisome elongation and abundance and peroxisomal fatty acid oxidation, which contributes to increased lipid accumulation in the liver.