BACKGROUND: Ischemic acute kidney injury (AKI) is a common syndrome associated with considerable mortality and healthcare costs. Up to now, the underlying pathogenesis of ischemic AKI remains incompletely understood, and specific strategies for early diagnosis and treatment of ischemic AKI are still lacking. Here, this study aimed to define the transcriptomic landscape of AKI patients through single-cell RNA sequencing (scRNA-seq) analysis in kidneys. METHODS: In this study, scRNA-seq technology was applied to kidneys from two ischemic AKI patients, and three human public scRNA-seq datasets were collected as controls. Differentially expressed genes (DEGs) and cell clusters of kidneys were determined. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, as well as the ligand-receptor interaction between cells, were performed. We also validated several DEGs expression in kidneys from human ischemic AKI and ischemia/reperfusion (I/R) injury induced AKI mice through immunohistochemistry staining. RESULTS: 15 distinct cell clusters were determined in kidney from subjects of ischemic AKI and control. The injured proximal tubules (PT) displayed a proapoptotic and proinflammatory phenotype. PT cells of ischemic AKI had up-regulation of novel pro-apoptotic genes including USP47 , RASSF4 , EBAG9 , IER3 , SASH1 , SEPTIN7 , and NUB1 , which have not been reported in ischemic AKI previously. Several hub genes were validated in kidneys from human AKI and renal I/R injury mice, respectively. Furthermore, PT highly expressed DEGs enriched in endoplasmic reticulum stress, autophagy, and retinoic acid-inducible gene I (RIG-I) signaling. DEGs overexpressed in other tubular cells were primarily enriched in nucleotide-binding and oligomerization domain (NOD)-like receptor signaling, estrogen signaling, interleukin (IL)-12 signaling, and IL-17 signaling. Overexpressed genes in kidney-resident immune cells including macrophages, natural killer T (NKT) cells, monocytes, and dendritic cells were associated with leukocyte activation, chemotaxis, cell adhesion, and complement activation. In addition, the ligand-receptor interactions analysis revealed prominent communications between macrophages and monocytes with other cells in the process of ischemic AKI. CONCLUSION Together, this study reveals distinct cell-specific transcriptomic atlas of kidney in ischemic AKI patients, altered signaling pathways, and potential cell-cell crosstalk in the development of AKI. These data reveal new insights into the pathogenesis and potential therapeutic strategies in ischemic AKI.
Humans ; Mice ; Animals ; Transcriptome/genetics* ; Ligands ; Kidney/metabolism* ; Acute Kidney Injury/metabolism* ; Ischemia/metabolism* ; Reperfusion Injury/metabolism* ; Sequence Analysis, RNA ; Adaptor Proteins, Signal Transducing/metabolism* ; Tumor Suppressor Proteins/metabolism*

OBJECTIVE: To evaluate the protective effect of recombinant Schistosoma japonicum cystatin (rSj-Cys) against acute kidney injury induced by acute liver failure and unravel the underlying mechanism, so as to provide insights into the clinical therapy of acute kidney injury. METHODS: Twenty-four male C57BL/6J mice at ages of 6 to 8 weeks were randomly divided into the normal control group, rSj-Cys control group, lipopolysaccharide (LPS)/D-galactosamine (D-GaIN) model group and LPS/D-GaIN + rSj-Cys treatment group, of 6 mice each group. Mice in the LPS/D-GaIN group and LPS/D-GaIN + rSj-Cys group were intraperitoneally injected with LPS (10 μg/kg) and D-GaIN (700 mg/kg), and mice in the LPS/D-GaIN + rSj-Cys group were additionally administered with rSj-Cys (1.25 mg/kg) by intraperitoneal injection 30 min post-modeling, while mice in the rSj-Cys group were intraperitoneally injected with rSj-Cys (1.25 mg/kg), and mice in the normal control group were injected with the normal volume of PBS. All mice were sacrificed 6 h post-modeling, and mouse serum and kidney samples were collected. Serum creatinine (Cr) and urea nitrogen (BUN) levels were measured, and the pathological changes of mouse kidney specimens were examined using hematoxylin-eosin (HE) staining. Serum tumor necrosis factor (TNF)-α and interleukin (IL)-6 levels were detected using enzyme-linked immunosorbent assay (ELISA), and the expression of inflammatory factors and pyroptosis-related proteins was quantified in mouse kidney specimens using immunohistochemistry. In addition, the expression of pyroptosis-related proteins and nuclear factor-kappa B (NF-κB) signaling pathway-associated proteins was determined in mouse kidney specimens using Western blotting assay. RESULTS: HE staining showed no remarkable abnormality in the mouse kidney structure in the normal control group and the rSj-Cys control group, and renal tubular injury was found in LPS/D-GaIN group, while the renal tubular injury was alleviated in LPS/D-GaIN+rSj-Cys treatment group. There were significant differences in serum levels of Cr (F = 46.33, P < 0.001), BUN (F = 128.60, P < 0.001), TNF-α (F = 102.00, P < 0.001) and IL-6 (F = 202.10, P < 0.001) among the four groups, and lower serum Cr [(85.35 ± 32.05) μmol/L], BUN [(11.90 ± 2.76) mmol/L], TNF-α [(158.27 ± 15.83) pg/mL] and IL-6 levels [(56.72 ± 4.37) pg/mL] were detected in the in LPS/D-GaIN + rSj-Cys group than in the LPS/D-GaIN group (all P values < 0.01). Immunohistochemical staining detected significant differences in TNF-α (F = 24.16, P < 0.001) and IL-10 (F = 15.07, P < 0.01) expression among the four groups, and lower TNF-α [(106.50 ± 16.57)%] and higher IL-10 expression [(91.83 ± 5.23)%] was detected in the LPS/D-GaIN + rSj-Cys group than in the LPS/D-GaIN group (both P values < 0.01). Western blotting and immunohistochemistry detected significant differences in the protein expression of pyroptosis-related proteins NOD-like receptor thermal protein domain associated protein 3 (NLRP3) (F = 24.57 and 30.72, both P values < 0.001), IL-1β (F = 19.24 and 22.59, both P values < 0.001) and IL-18 (F = 16.60 and 19.30, both P values < 0.001) in kidney samples among the four groups, and lower NLRP3, IL-1β and IL-18 expression was quantified in the LPS/D-GaIN + rSj-Cys treatment group than in the LPS/D-GaIN group (P values < 0.05). In addition, there were significant differences in the protein expression of NF-κB signaling pathway-associated proteins p-NF-κB p-P65/NF-κB p65 (F = 71.88, P < 0.001), Toll-like receptor (TLR)-4 (F = 45.49, P < 0.001) and p-IκB/IκB (F = 60.87, P < 0.001) in mouse kidney samples among the four groups, and lower expression of three NF-κB signaling pathway-associated proteins was determined in the LPS/D-GaIN + rSj-Cys treatment group than in the LPS/D-GaIN group (all P values < 0.01). CONCLUSIONS rSj-Cys may present a protective effect against acute kidney injury caused by acute liver failure through inhibiting inflammation and pyroptosis and downregulating the NF-κB signaling pathway.
Mice ; Male ; Animals ; Interleukin-10 ; Tumor Necrosis Factor-alpha/genetics* ; NF-kappa B/therapeutic use* ; Interleukin-18/therapeutic use* ; Schistosoma japonicum/metabolism* ; Interleukin-6/therapeutic use* ; Lipopolysaccharides/therapeutic use* ; NLR Family, Pyrin Domain-Containing 3 Protein ; Mice, Inbred C57BL ; Acute Kidney Injury/drug therapy* ; Liver Failure, Acute ; Cystatins/therapeutic use*

Acute kidney injury (AKI) is a common clinical syndrome and an independent risk factor of chronic kidney disease and end-stage renal failure. At present, the treatments of AKI are still very limited and the morbidity and mortality of AKI are rising. Non-coding RNAs (ncRNAs), including microRNAs, long non-coding RNAs and circular RNAs (circRNAs), are RNAs that are transcribed from the genome, but not translated into proteins. It has been widely reported that ncRNA is involved in AKI caused by ischemia reperfusion injury (IRI), drugs and sepsis through different molecular biological mechanisms, such as apoptosis and oxidative stress response. Therefore, ncRNAs are expected to become a new target for clinical prevention and treatment of AKI and a new biomarker for early warning of the occurrence and prognosis of AKI. Here, the role and mechanism of ncRNA in AKI and the research progress of ncRNA as biomarkers are reviewed.
Acute Kidney Injury/metabolism* ; Humans ; MicroRNAs/metabolism* ; RNA, Circular ; RNA, Long Noncoding/genetics* ; RNA, Untranslated/genetics* ; Reperfusion Injury/genetics*

Few studies have described the key features and prognostic roles of lung microbiota in patients with severe community-acquired pneumonia (SCAP). We prospectively enrolled consecutive SCAP patients admitted to ICU. Bronchoscopy was performed at bedside within 48 h of ICU admission, and 16S rRNA gene sequencing was applied to the collected bronchoalveolar lavage fluid. The primary outcome was clinical improvements defined as a decrease of 2 categories and above on a 7-category ordinal scale within 14 days following bronchoscopy. Sixty-seven patients were included. Multivariable permutational multivariate analysis of variance found that positive bacteria lab test results had the strongest independent association with lung microbiota (R² = 0.033; P = 0.018), followed by acute kidney injury (AKI; R² = 0.032; P = 0.011) and plasma MIP-1β level (R² = 0.027; P = 0.044). Random forest identified that the families Prevotellaceae, Moraxellaceae, and Staphylococcaceae were the biomarkers related to the positive bacteria lab test results. Multivariable Cox regression showed that the increase in α-diversity and the abundance of the families Prevotellaceae and Actinomycetaceae were associated with clinical improvements. The positive bacteria lab test results, AKI, and plasma MIP-1β level were associated with patients' lung microbiota composition on ICU admission. The families Prevotellaceae and Actinomycetaceae on admission predicted clinical improvements.
Acute Kidney Injury/complications* ; Bacteria/classification* ; Chemokine CCL4/blood* ; Community-Acquired Infections/microbiology* ; Humans ; Lung ; Microbiota/genetics* ; Pneumonia, Bacterial/diagnosis* ; Prognosis ; RNA, Ribosomal, 16S/genetics*

INTRODUCTION: To study the prevalence of hepatitis C virus (HCV) infection in blood donor (BD), haemodialysis (HD) and intravenous drug user (IVDU) populations in Singapore and assess the IL28B polymorphism if HCV positive. METHODS: The BD population were healthy volunteers, the HD population were patients who were on haemodialysis for at least six months of follow-up between January 2009 and December 2014. IVDU population was from inmates at halfway houses who consented. RESULTS: Between 2011 and 2014, of 161,658 individuals who underwent screening prior to blood donation, 95 (0.059%) were positive for HCV. Of the 42 sera available, common genotypes (GTs) were GT-3 (47.6%) and GT-1 (31.0%). Of 1,575 HD patients, 2.2% were anti-HCV positive. The HCV GT distribution was HCV GT-1 (32.4%), HCV GT-3 (20.5%) and GT-6 (8.8%). 83 halfway house inmates were screened. Of the 47 IVDUs, 36.2% were anti-HCV positive with predominant GT-3 (%). IL28B polymorphism was noted to be CC predominantly 85.3%. CONCLUSION Prevalence of HCV infection has decreased in both the BD and HD populations. However, it remains high in the IVDU population. GT-1 remains the most common in the HD population; however, GT-3 infection is now more common among the BD population in Singapore. IL28B - CC is the predominant variant among the HCV-infected individuals in Singapore.
Acute Kidney Injury ; blood ; complications ; Adult ; Alleles ; Blood Donors ; Female ; Genotype ; Hepatitis C ; epidemiology ; Humans ; Interleukins ; genetics ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; Prevalence ; Renal Dialysis ; Singapore ; epidemiology ; Substance Abuse, Intravenous ; blood ; epidemiology ; Young Adult

OBJECTIVE: : To screen genes involved in mitochondrial DNA (mtDNA) damage repair in rats with septic acute kidney injury (SAKI). METHODS: : Forty male C57BL/6J mice were randomly divided into SAKI group (=28) and sham operation group (=12). The SAKI mouse model was established by cecal ligation and puncture. Blood and kidney samples were collected at 8, 24, and 48 h after surgery. Serum creatinine and urea nitrogen were measured by a dry biochemical analyzer. Serum inflammatory cytokines were detected by ELISA. Histopathological changes were observed with HE staining. The mtDNA damage repair related genes were screened by RNA sequencing and bioinformatics analysis; the mRNA and protein expression levels of related genes were detected by real-time quantitative RT-PCR and immunohistochemisry, respectively. RESULTS: : Symptoms of sepsis were observed in SAKI group, and 16 out of 28 mice were died in the SAKI group; serum TNF-α, IL-6, creatinine and urea nitrogen levels were higher than those in the sham group (<0.05 or <0.01). Histopathological examination in SAKI group showed that renal tubular epithelial cells were swollen, inflammatory cells infiltrated, and a large number of cell vacuoles were seen, suggesting successful modeling. Mitochondrial DNA damage repair related genes and were screened out. The expression of these genes was detected by real-time RT-PCR, and the results were consistent with RNA sequencing trends. Immunohistochemical staining showed that Gadd45α was mainly expressed in the nucleus of renal tubular epithelial cells, and the positive rate of Gadd45α in SAKI group was higher than that in the sham operation group (<0.05). CONCLUSIONS : and genes are involved in mtDNA damage repair in rats with SAKI, indicating that these genes may be used as new targets for prevention and treatment of SAKI.
Acute Kidney Injury ; physiopathology ; Animals ; Blood Urea Nitrogen ; Creatinine ; blood ; DNA Repair ; genetics ; DNA, Mitochondrial ; Male ; Mice ; Mice, Inbred C57BL ; Random Allocation ; Rats ; Sepsis ; physiopathology

The infant (a girl aged 6 months) was admitted to the hospital because of oliguria and acute renal dysfunction. The laboratory examination results showed serious metabolic acidosis and increased blood urea nitrogen and serum creatinine levels. The patient continued to be anuric after 10 days of treatment with continuous renal replacement therapy (CRRT). she died a day later. The family history showed that the patient's sister died of acute renal failure 6 months after birth. The genomic sequencing results showed AGXT mutation in the patient and confirmed the diagnosis of primary hyperoxaluria type 1 (PH1). Her parents were heterozygous carriers. PH1 should be considered when the children have abnormal renal function or recurrent renal calculi or have a family history of these symptoms. AGXT gene analysis is an important method for PH1 diagnosis.
Acute Kidney Injury ; etiology ; Female ; Humans ; Hyperoxaluria, Primary ; complications ; Infant ; Mutation ; Oliguria ; etiology ; Transaminases ; genetics

OBJECTIVES: To study the differential genes expression in the early stage of acute renal ischemia-reperfusion injury and explore potential molecular mechanisms. METHODS: The ischemia-reperfusion model was made via clamping renal artery of rat. The microarray detection and bioinformatics analyzing of the genes expression were performed. Differentially expressed genes were screened and related cellular activities and signaling pathways were analyzed in early stage of acute kidney injury. Meanwhile, molecules closely relative to acute kidney injury were explored by establishing a biological network of the differentially expressed genes, and the results were verified by real-time PCR. RESULTS: A total of 151 genes showed differential expression in this study, including 132 up-regulated and 19 down-regulated genes. Cell proliferation, cytokines mediated signaling transduction and immune responses were greatly enriched by GO and KEGG analysis. The results of real-time PCR showed that compared with control groups, three selected genes （ANXA1, PHLDA1 and KLF6） which related to the acute kidney injury had an obvious differential expression in the early stage of disease. The multiple of increase was essentially the same as the multiple detected by microarray. CONCLUSIONS This study shows differential gene expression profile, related biological processes and signaling pathways involved in the early stage of acute kidney injury. ANXA1, PHLDA1 and KLF6 may play a role in the pathogenesis of acute kidney injury.
Acute Kidney Injury/genetics* ; Animals ; Annexin A1/genetics* ; Apoptosis Regulatory Proteins/genetics* ; Gene Expression ; Kidney/pathology* ; Kruppel-Like Factor 6/genetics* ; Rats ; Real-Time Polymerase Chain Reaction ; Reperfusion Injury/genetics* ; Signal Transduction

Aging is associated with progressive functional deterioration and structural changes in the kidney. Changes in the activity or responsiveness of the renin-angiotensin system (RAS) occur with aging. RAS changes predispose the elderly to various fluid and electrolyte imbalances as well as acute kidney injury and chronic kidney disease. Among the multiple pathways involved in renal aging, the RAS plays a central role. This review summarizes the association of the RAS with structural and functional changes in the aging kidney and age-related renal injury, and describes the underlying mechanisms of RAS-related renal aging. An improved understanding of the renal aging process may lead to better individualized care of the elderly and improved renal survival in age-related diseases.
Acute Kidney Injury/etiology/metabolism/physiopathology ; Age Factors ; Aging/genetics/*metabolism ; Animals ; Glucuronidase/genetics/metabolism ; Humans ; Kidney/*metabolism/physiopathology ; Kidney Diseases/*etiology/genetics/metabolism/physiopathology ; Prognosis ; *Renin-Angiotensin System ; Risk Factors

BACKGROUNDMycophenolate mofetil (MMF) has been used to prevent transplant rejection for many years and has been shown to have protective effects against renal failure. The objective was to investigate the effect of MMF on monocyte Toll-like receptor 4 (TLR4) signaling in the early stages of renal ischemia/reperfusion injury (IRI) of mice.

METHODSSixty BALB/C mice were randomly divided into two groups: an IRI group, in which renal IRI was induced by clamping the renal pedicles for 45 minutes, and an MMF group, in which MMF was given (40 mg×kg(-1)×d(-1), intraperitoneally) from 2 days before renal IRI. The plasma creatinine level and renal tissue damage of each group mice were observed 6, 12, 24, and 48 hours after reperfusion. The concentration of plasma high-mobility group box 1 (HMGB-1) (TLR4 ligand), interleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor α (TNF-α) and the expression of TLR-4 on monocytes were determined.

RESULTSThe plasma creatinine concentration in the MMF group was lower compared to the IRI group (after reperfusion of 6, 12, 24, or 48 hours, P < 0.05). Pathological analysis showed that the renal damage was slighter, TLR-4 expression was reduced (after reperfusion of 6, 12, 24, or 48 hours, P < 0.05), and the concentration of cytokines in the plasma was lower (P < 0.05) in the MMF group. No differences in the concentrations of HMGB-1 were observed (P > 0.05).

CONCLUSIONMonocyte TLR4 signaling is important in the early stage of kidney IRI, but MMF can inhibit it and improve renal function.

Acute Kidney Injury ; blood ; drug therapy ; metabolism ; Animals ; Chemokine CCL2 ; genetics ; metabolism ; Creatinine ; blood ; Cytokines ; blood ; HMGB1 Protein ; genetics ; metabolism ; Male ; Mice ; Mice, Inbred BALB C ; Monocytes ; drug effects ; metabolism ; Mycophenolic Acid ; analogs & derivatives ; therapeutic use ; Random Allocation ; Reperfusion Injury ; blood ; drug therapy ; metabolism ; Signal Transduction ; drug effects ; genetics ; Toll-Like Receptor 4 ; genetics ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism