Diabetic kidney disease (DKD) is the main cause of chronic kidney disease (CKD) and progresses faster in males than in females. We identify sex-based differences in kidney metabolism and in the blood ...metabolome of male and female individuals with diabetes. Primary human proximal tubular epithelial cells (PTECs) from healthy males displayed increased mitochondrial respiration, oxidative stress, apoptosis, and greater injury when exposed to high glucose compared with PTECs from healthy females. Male human PTECs showed increased glucose and glutamine fluxes to the TCA cycle, whereas female human PTECs showed increased pyruvate content. The male human PTEC phenotype was enhanced by dihydrotestosterone and mediated by the transcription factor HNF4A and histone demethylase KDM6A. In mice where sex chromosomes either matched or did not match gonadal sex, male gonadal sex contributed to the kidney metabolism differences between males and females. A blood metabolomics analysis in a cohort of adolescents with or without diabetes showed increased TCA cycle metabolites in males. In a second cohort of adults with diabetes, females without DKD had higher serum pyruvate concentrations than did males with or without DKD. Serum pyruvate concentrations positively correlated with the estimated glomerular filtration rate, a measure of kidney function, and negatively correlated with all-cause mortality in this cohort. In a third cohort of adults with CKD, male sex and diabetes were associated with increased plasma TCA cycle metabolites, which correlated with all-cause mortality. These findings suggest that differences in male and female kidney metabolism may contribute to sex-dependent outcomes in DKD.
Abstract Half of patients with renal cell carcinoma (RCC) develop metastases. New and noninvasive biomarkers are needed for the diagnosis of RCC. The study aims to develop an EV‐based assay for the ...detection of RCC using a highly sensitive nanoparticle‐aided time‐resolved fluorescence immunoassay (NP‐TRFIA). To confirm the presence of tetraspanins on EVs, size exclusion chromatography is used to separate EV‐ and PE‐fractions from RCC4, 786‐O, and HEK293 cell lines. EV‐ and PE‐fractions are quantified using NP‐TRFIA assays established for CD9, CD63, CD81, and CD151. Tetraspanins are measured from RCC CCM and serum samples of RCC ( n = 14), benign ( n = 17), and healthy ( n = 9) individuals. Among the tetraspanins, CD63 exhibits 3‐5‐fold higher expression on RCC4 and 786‐O CCM compared to HEK293. A sandwich CD63‐CD63 assay demonstrates significant discrimination of RCC patients from benign ( p = 0.0003), and healthy ( p = 0.005) individuals, respectively. Similarly, the CD81‐CD81 assay also enables significant separation of RCC patients compared to benign ( p = 0.014), and healthy ( p = 0.003) controls, respectively. This suggests that RCC cell lines and serum of RCC patients show higher amounts of CD63‐ and CD81‐EVs compared to controls. Detection of these EVs using NP‐TRFIA approach may play a vital role in the detection of RCC.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The availability of blood‐based markers to predict response of a solid tumor to treatment, estimate patient prognosis and diagnose relapse well before clinical symptoms arise, is a long‐standing hope ...in clinical oncology. Ideally, assays designed to provide such information should be inexpensive (at least in the foreseeable future), simple, and, of course, predictive of the clinical evolution of the disease. While early research focused on circulating glycosylated tumor‐derived protein biomarkers, the focus is now rapidly shifting to new opportunities, such as circulating tumor cells, extracellular vesicles, micro‐RNAs and cancer‐derived cell‐free DNA a.k.a. circulating tumor‐derived DNA (ctDNA).
Kallioniemi and colleagues comment on the new report by Lao Saal's team making the case for serial measurement of circulating tumor DNA (ctDNA) as a robust and accurate occult metastatic disease biomarker in patients diagnosed with primary breast cancer.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Background: We compared performance of different methods for urinary extracellular vesicle (uEV) harvest and the respective transcriptome yields for biomarker identification in diabetic kidney ...disease (DKD). Methods: Type 1 diabetic (T1D) patients and normal controls were included in the study. uEVs were isolated from 20 to 40 ml of 24 h urine collection by ultracentrifugation (UC), hydrostatic filtration dialysis (HFD) or kit-based isolation (KI). Quality of uEV yield was analysed with EM and Western blotting (WB). Isolated RNAs were profiled with Bioanalyzer Pico kit and subjected to RNAseq using HiSeq 2000 (Illumina) pair-end (2 x 100) protocol. Output reads were aligned to human reference genome and counted using GENCODE annotations. We used gene length normalized values FKPM (fragments per kilobase of exon per million) as expression measurement for genes. Results: The isolated uEVs appeared typical at EM and were positive for CD9 and kidney-derived podocalyxin in WB. The size distribution of uEVs (by NTA) was similar in HFD and UC while KI samples were enriched in smaller vesicles (up to 300 nm).The RNA yield was slightly higher in UC and KI samples while sufficient for RNAseq in all. The number of reads for KI samples was lower and the intron content higher than in UC or HFD. For UC samples, we detected (FKPM >1) average of 13,161 genes and high expression (FPKM >5) of kidney specific genes (SLC12A3, SLC12A1, LGALS1, ATP6V1B1, NPHS2, AQP3, AQP2, SLC22A12). Full analysis of 182 kidney specific genes showed >70% (total 132) of the genes in uEVs. Principal component analysis of these distinguished macro-albuminuric from normoalbuminuric T1D patients. Six genes were differentially expressed in DKD (Puncorrected <0.001 and fold change >1.5 or <0.66). The highest expressed genes in EVs (N = 5153, FKPM >10) were enriched (P > 10-11) in pathways of cellular metabolism (oxidative phosphorylation and TCA cycle), mitochondrial, vesicle trafficking and ribosome functions. Pathway and gene enrichment analyses (P < 0.05, N = 956) differentially expressed genes implicated (P < 0.002) TGF-beta and PI3K-Akt signalling as well as immune pathways in DKD. Summary/Conclusion: We show that uEV transcriptome captures the kidney specific transcriptome and differentiates T1D patients from controls while full method standardization is needed.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A glycosyl hydrolase family 38 enzyme, neutral α-mannosidase, has been proposed to be involved in hydrolysis of cytosolic free oligosaccharides originating either from ER-misfolded glycoproteins or ...the N-glycosylation process. Although this enzyme has been isolated from the cytosol, it has also been linked to the ER by subcellular fractionations. We have studied the subcellular localization of neutral α-mannosidase by immunofluorescence microscopy and characterized the human recombinant enzyme with natural substrates to elucidate the biological function of this enzyme. Immunofluorescence microscopy showed neutral α-mannosidase to be absent from the ER, lysosomes, and autophagosomes, and being granularly distributed in the cytosol. In experiments with fluorescent recovery after photo bleaching, neutral α-mannosidase had slower than expected two-phased diffusion in the cytosol. This result together with the granular appearance in immunostaining suggests that portion of the neutral α-mannosidase pool is somehow complexed. The purified recombinant enzyme is a tetramer and has a neutral pH optimum for activity. It hydrolyzed Man9GlcNAc to Man5GlcNAc in the presence of Fe2+, Co2+, and Mn2+, and uniquely to neutral α-mannosidases from other organisms, the human enzyme was more activated by Fe2+ than Co2+. Without activating cations the main reaction product was Man8GlcNAc, and Cu2+ completely inhibited neutral α-mannosidase. Our findings from enzyme-substrate characterizations and subcellular localization studies support the suggested role for neutral α-mannosidase in hydrolysis of soluble cytosolic oligomannosides.
A glycosyl hydrolase family 38 enzyme, neutral alpha-mannosidase, has been proposed to be involved in hydrolysis of cytosolic free oligosaccharides originating either from ER-misfolded glycoproteins ...or the N-glycosylation process. Although this enzyme has been isolated from the cytosol, it has also been linked to the ER by subcellular fractionations. We have studied the subcellular localization of neutral alpha-mannosidase by immunofluorescence microscopy and characterized the human recombinant enzyme with natural substrates to elucidate the biological function of this enzyme. Immunofluorescence microscopy showed neutral alpha-mannosidase to be absent from the ER, lysosomes, and autophagosomes, and being granularly distributed in the cytosol. In experiments with fluorescent recovery after photo bleaching, neutral alpha-mannosidase had slower than expected two-phased diffusion in the cytosol. This result together with the granular appearance in immunostaining suggests that portion of the neutral alpha-mannosidase pool is somehow complexed. The purified recombinant enzyme is a tetramer and has a neutral pH optimum for activity. It hydrolyzed Man(9)GlcNAc to Man(5)GlcNAc in the presence of Fe(2+), Co(2+), and Mn(2+), and uniquely to neutral alpha-mannosidases from other organisms, the human enzyme was more activated by Fe(2+) than Co(2+). Without activating cations the main reaction product was Man(8)GlcNAc, and Cu(2+) completely inhibited neutral alpha-mannosidase. Our findings from enzyme-substrate characterizations and subcellular localization studies support the suggested role for neutral alpha-mannosidase in hydrolysis of soluble cytosolic oligomannosides.
A glycosyl hydrolase family 38 enzyme, neutral α-mannosidase, has been proposed to be involved in hydrolysis of cytosolic free oligosaccharides originating either from ER-misfolded glycoproteins or ...the N-glycosylation process. Although this enzyme has been isolated from the cytosol, it has also been linked to the ER by subcellular fractionations. We have studied the subcellular localization of neutral α-mannosidase by immunofluorescence microscopy and characterized the human recombinant enzyme with natural substrates to elucidate the biological function of this enzyme. Immunofluorescence microscopy showed neutral α-mannosidase to be absent from the ER, lysosomes, and autophagosomes, and being granularly distributed in the cytosol. In experiments with fluorescent recovery after photo bleaching, neutral α-mannosidase had slower than expected two-phased diffusion in the cytosol. This result together with the granular appearance in immunostaining suggests that portion of the neutral α-mannosidase pool is somehow complexed. The purified recombinant enzyme is a tetramer and has a neutral pH optimum for activity. It hydrolyzed Man9 GlcNAc to Man5 GlcNAc in the presence of Fe2+ , Co2+ , and Mn2+ , and uniquely to neutral α-mannosidases from other organisms, the human enzyme was more activated by Fe2+ than Co2+ . Without activating cations the main reaction product was Man8 GlcNAc, and Cu2+ completely inhibited neutral α-mannosidase. Our findings from enzyme-substrate characterizations and subcellular localization studies support the suggested role for neutral α-mannosidase in hydrolysis of soluble cytosolic oligomannosides.
A glycosyl hydrolase family 38 enzyme, neutral alpha-mannosidase, has been proposed to be involved in hydrolysis of cytosolic free oligosaccharides originating either from ER-misfolded glycoproteins ...or the N-glycosylation process. Although this enzyme has been isolated from the cytosol, it has also been linked to the ER by subcellular fractionations. We have studied the subcellular localization of neutral alpha-mannosidase by immunofluorescence microscopy and characterized the human recombinant enzyme with natural substrates to elucidate the biological function of this enzyme. Immunofluorescence microscopy showed neutral alpha-mannosidase to be absent from the ER, lysosomes, and autophagosomes, and being granularly distributed in the cytosol. In experiments with fluorescent recovery after photo bleaching, neutral alpha-mannosidase had slower than expected two-phased diffusion in the cytosol. This result together with the granular appearance in immunostaining suggests that portion of the neutral alpha-mannosidase pool is somehow complexed. The purified recombinant enzyme is a tetramer and has a neutral pH optimum for activity. It hydrolyzed Man(9)GlcNAc to Man(5)GlcNAc in the presence of Fe(2+), Co(2+), and Mn(2+), and uniquely to neutral alpha-mannosidases from other organisms, the human enzyme was more activated by Fe(2+) than Co(2+). Without activating cations the main reaction product was Man(8)GlcNAc, and Cu(2+) completely inhibited neutral alpha-mannosidase. Our findings from enzyme-substrate characterizations and subcellular localization studies support the suggested role for neutral alpha-mannosidase in hydrolysis of soluble cytosolic oligomannosides.
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