Evaluation of the QIAstat-Dx Respiratory SARS-CoV-2 panel, a rapid multiplex PCR method for the diagnosis of COVID-19.

INTRODUCTION: Rapid, simple, and accurate methods are required to diagnose coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This study aimed to evaluate the performance of the QIAstat-Dx Respiratory SARS-CoV-2 Panel (QIAstat-SARS-CoV-2), a rapid multiplex PCR assay for SARS-CoV-2 detection. METHODS: Nasopharyngeal swabs (NPS) that were obtained from patients with COVID-19 who were diagnosed at the National Center for Global Health and Medicine were used in this study. When the NPS samples were found to be negative for SARS-CoV-2 after treatment, they were used as negative samples. We evaluated the performance of the QIAstat-SARS-CoV-2 comparing SARS-CoV-2 detection with the National Institute of Infectious Diseases in Japan-recommended real-time polymerase chain reaction (RT-PCR) method (NIID-RT-PCR). RESULTS: In total, 45 NPS samples were analyzed. The proportion of overall agreement between QIAstat-SARS-CoV-2 and NIID-RT-PCR on 45 samples was 91.0% with a sensitivity of 84.0% (21/25), specificity at 100% (20/20), negative predictive value at 83.3% (20/24), and positive predictive value at 100% (21/21). There were no patients with co-infections with pathogens other than SARS-CoV-2. CONCLUSIONS: QIAstat-SARS-CoV-2 showed a high agreement in comparison with the NIID-RT-PCR for the detection of SARS-CoV-2. The QIAstat-SARS-CoV-2 also provided a rapid and accurate diagnosis for COVID-19, even when the concurrent detection of other respiratory pathogens was desired, and therefore, has the potential to direct appropriate therapy and infection control precautions.

Independent risk factors of rapid glomerular filtration rate decline in patients with type 2 diabetes with preserved kidney function and normoalbuminuria: A multicenter cohort study.

AIMS/INTRODUCTION: Research on the incidence and underlying mechanisms of rapid renal function decline in patients with type 2 diabetes mellitus with preserved renal function and normoalbuminuria is limited. This study aimed to investigate the involvement of hemoglobin level as a risk factor for rapid decliners among patients with type 2 diabetes with preserved renal function and normoalbuminuria. MATERIALS AND METHODS: This was a retrospective observational study of 242 patients with type 2 diabetes with a baseline estimated glomerular filtration rate of ≥60 mL/min/1.73 m2 and normoalbuminuria (<30 mg/gCr), followed up for >1 year. The annual rate of estimated glomerular filtration rate decline during the follow-up period was calculated using least square regression analysis; rapid decliners defined at ≥3.3%/year. Risk factors associated with rapid decliners were identified using a logistic regression analysis of variables previously identified as risk factors of rapid decliners. RESULTS: The median follow-up period was 6.7 years, and 34 patients showed rapid decliners. On multivariate analysis, lower baseline hemoglobin level was a risk factor of rapid decliners (odds ratio 0.69, 95% confidence interval 0.47-0.99; P = 0.045). Furthermore, the baseline hemoglobin levels were correlated positively with iron and ferritin levels, implying that an impaired iron metabolism might cause lower hemoglobin levels in rapid decliners. CONCLUSIONS: In patients with type 2 diabetes with preserved renal function and normoalbuminuria, lower hemoglobin levels were a risk factor for rapid decliners, where disturbed iron metabolism might precede the development of diabetic kidney disease.

Hepatic FASN deficiency differentially affects nonalcoholic fatty liver disease and diabetes in mouse obesity models.

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes are interacting comorbidities of obesity, and increased hepatic de novo lipogenesis (DNL), driven by hyperinsulinemia and carbohydrate overload, contributes to their pathogenesis. Fatty acid synthase (FASN), a key enzyme of hepatic DNL, is upregulated in association with insulin resistance. However, the therapeutic potential of targeting FASN in hepatocytes for obesity-associated metabolic diseases is unknown. Here, we show that hepatic FASN deficiency differentially affects NAFLD and diabetes depending on the etiology of obesity. Hepatocyte-specific ablation of FASN ameliorated NAFLD and diabetes in melanocortin 4 receptor-deficient mice but not in mice with diet-induced obesity. In leptin-deficient mice, FASN ablation alleviated hepatic steatosis and improved glucose tolerance but exacerbated fed hyperglycemia and liver dysfunction. The beneficial effects of hepatic FASN deficiency on NAFLD and glucose metabolism were associated with suppression of DNL and attenuation of gluconeogenesis and fatty acid oxidation, respectively. The exacerbation of fed hyperglycemia by FASN ablation in leptin-deficient mice appeared attributable to impairment of hepatic glucose uptake triggered by glycogen accumulation and citrate-mediated inhibition of glycolysis. Further investigation of the therapeutic potential of hepatic FASN inhibition for NAFLD and diabetes in humans should thus consider the etiology of obesity.

[Perspective of proteomic studies for discovering biomarkers of diabetes and obesity].

The prevalence of diabetes is rapidly increasing worldwide, leading to an increasing risk of microangiopathic complications. To identify biomarkers of diabetic microangiopathy that are useful for prevention and early treatment of diabetic complications, proteomic analyses of clinical samples from diabetic patients have been performed. However, as diabetes is a systemic disease, it is difficult to define the pathologic conditions and foci causing changes in proteomic profile of clinical samples from diabetics. An approach using multiple reaction monitoring may be useful to systemically identify diabetic microangiopathy biomarkers from blood and urine samples from diabetic patients.

Podocyte-specific deletion of tubular sclerosis complex 2 promotes focal segmental glomerulosclerosis and progressive renal failure.

Obesity can initiate and accelerate the progression of kidney diseases. However, it remains unclear how obesity affects renal dysfunction. Here, we show that a newly generated podocyte-specific tubular sclerosis complex 2 (Tsc2) knockout mouse model (Tsc2Δpodocyte) develops proteinuria and dies due to end-stage renal dysfunction by 10 weeks of age. Tsc2Δpodocyte mice exhibit an increased glomerular size and focal segmental glomerulosclerosis, including podocyte foot process effacement, mesangial sclerosis and proteinaceous casts. Podocytes isolated from Tsc2Δpodocyte mice show nuclear factor, erythroid derived 2, like 2-mediated increased oxidative stress response on microarray analysis and their autophagic activity is lowered through the mammalian target of rapamycin (mTOR)-unc-51-like kinase 1 pathway. Rapamycin attenuated podocyte dysfunction and extends survival in Tsc2Δpodocyte mice. Additionally, mTOR complex 1 (mTORC1) activity is increased in podocytes of renal biopsy specimens obtained from obese patients with chronic kidney disease. Our work shows that mTORC1 hyperactivation in podocytes leads to severe renal dysfunction and that inhibition of mTORC1 activity in podocytes could be a key therapeutic target for obesity-related kidney diseases.

Urinary afamin levels are associated with the progression of diabetic nephropathy.

AIMS: In this study, we applied quantitative proteomic analysis to identify urinary proteins associated with diabetic nephropathy (DN). METHODS: Two-dimensional image-converted analysis of liquid chromatography and mass spectrometry detected the proteins differentially excreted between normoalbuminuric and macroalbuminuric patients with type 2 diabetes mellitus (T2DM) (n = 6 each). Urinary levels of excreted proteins were measured by multiple reaction monitoring (MRM) analysis using an independent sample set (n = 77). Urinary afamin levels were measured by ELISA in T2DM and DN patients enrolled in this cohort study (n = 203). RESULTS: One-hundred-four proteins displayed significant alterations in excretion. Nine of these candidates were validated by MRM analysis. Among them, the levels of afamin, CD44 antigen, and lysosome-associated membrane glycoprotein 2, which have not previously been implicated in DN, were significantly associated with both the urinary albumin to creatinine ratio (ACR) and eGFR. We further measured afamin levels in urine collected from T2DM patients who did not yet have significant kidney disease (ACR < 300 mg/g or eGFR change rate ≤ 3.3%/year). The urinary afamin to creatinine ratio (Afa/Cre) was significantly higher in patients who progressed to a more severe DN stage or had early renal decline than in patients who did not. CONCLUSIONS: Afa/Cre was significantly increased in T2DM patients who subsequently developed DN. Afa/Cre may be useful to predict patients with T2DM at high risk of nephropathy before the development of macroalbuminuria or reduced kidney function, although further validation studies in a larger population are needed.

Susceptibilities of epicardial and subcutaneous fat tissue for browning-gene expression and diet-induced volume reduction are different.

The upregulation of brown or brown-like beige adipocytes is a potential strategy for the prevention or treatment of diabetes and coronary artery diseases in obese patients. Epicardial adipose tissue (EAT) differs significantly from subcutaneous fat tissue (SAT) in metabolic properties. To investigate properties of EAT further, thermogenesis gene expression was investigated in human autopsy and murine samples, and adipocytes differentiated from EAT mesenchymal cells. Subsequently, analyzed EAT volume alterations were observed to be associated with weight reduction in obese patients by imaging. Gene expression analyses of autopsy samples revealed that UCP­1 mRNA levels in EAT were significantly increased compared with SAT, and ß3­adrenergic receptor (AR) levels tended to be increased; this finding was verified in comparing EAT with SAT in mice. Browning stimulation of human EAT­derived MCs increased uncoupling protein­1 and ß3­AR levels by 3.2 fold­ and 12.6­fold compared with SAT­derived MCs, respectively. Subsequent imaging for EAT volume measurement using multi­detector computed tomography in 10 obese patients revealed that mean EAT volumes did not significantly decrease following weight loss therapy. The EAT volume alterations were not correlated with weight changes, whereas positive correlations were observed in SAT and visceral adipose tissue. Therefore, the studies in man and mouse on EAT properties demonstrated that susceptibilities of EAT and SAT for browning­gene expression and diet­induced volume reduction were grossly different. The data suggest a potential association of EAT with local thermogenetic and metabolic homeostasis in cardiac and/or cardiovascular cells, in conjunction with systemic energy metabolism.

PHD3 regulates glucose metabolism by suppressing stress-induced signalling and optimising gluconeogenesis and insulin signalling in hepatocytes.

Glucagon-mediated gene transcription in the liver is critical for maintaining glucose homeostasis. Promoting the induction of gluconeogenic genes and blocking that of insulin receptor substrate (Irs)2 in hepatocytes contributes to the pathogenesis of type 2 diabetes. However, the molecular mechanism by which glucagon signalling regulates hepatocyte metabolism is not fully understood. We previously showed that a fasting-inducible signalling module consisting of general control non-repressed protein 5, co-regulator cAMP response element-binding protein binding protein/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2, and protein kinase A is required for glucagon-induced transcription of gluconeogenic genes. The present study aimed to identify the downstream effectors of this module in hepatocytes by examining glucagon-induced potential target genes. One of these genes was prolyl hydroxylase domain (PHD)3, which suppressed stress signalling through inhibition of the IκB kinase-nuclear factor-κB pathway in a proline hydroxylase-independent manner to maintain insulin signalling. PHD3 was also required for peroxisome proliferator-activated receptor γ coactivator 1α-induced gluconeogenesis, which was dependent on proline hydroxylase activity, suggesting that PHD3 regulates metabolism in response to glucagon as well as insulin. These findings demonstrate that glucagon-inducible PHD3 regulates glucose metabolism by suppressing stress signalling and optimising gluconeogenesis and insulin signalling in hepatocytes.

A novel angiogenic peptide, ΔADT: A truncated adrenotensin peptide revealed by secretory peptidome analysis of human retinal pericytes.

Retinal pericytes play an important role in the maintenance of retinal microvascular homeostasis. We performed a secretory peptidome of primary human retinal pericytes. Using liquid chromatography-tandem mass spectrometry analysis in the culture medium of retinal pericytes, we identified 256 peptides derived from 114 proteins, and identified a novel partial fragment Leu163-His183 (termed ΔADT) of adrenotensin (ADT). To elucidate the role of ΔADT as a soluble mediator of pericyte-endothelial cell interactions, we investigated the bioactivity of ΔADT in human retinal microvascular endothelial cells (HRMVECs). The cell proliferation assay indicated that the proliferation of HRMVECs was promoted by ADT or ΔADT. Moreover, ΔADT had a greater growth promoting effect than ADT in HRMVECs and induced migration and tube formation of HRMVECs. We also observed actin reorganization and that the levels of phosphorylated focal adhesion kinase in ΔADT stimulated HRMVECs. These results showed that ΔADT induces profound actin reorganization and increases the levels of phosphorylated focal adhesion kinase. Collectively, our study showed that ΔADT has an angiogenic activity, and suggested that ΔADT is a novel angiogenic peptide.

Alleviation of lipopolysaccharide/d-galactosamine-induced liver injury in leukocyte cell-derived chemotaxin 2 deficient mice.

Leukocyte cell-derived chemotaxin 2 (LECT2) is a secreted pleiotropic protein that is mainly produced by the liver. We have previously shown that LECT2 plays an important role in the pathogenesis of inflammatory liver diseases. Lipopolysaccharide/d-galactosamine (LPS/d-GalN)-induced acute liver injury is a known animal model of fulminant hepatic failure. Here we found that this hepatic injury was alleviated in LECT2-deficient mice. The levels of TNF-α and IFN-γ, which mediate this hepatitis, had significantly decreased in these mice, with the decrease in IFN-γ production notably greater than that in TNF-α. We therefore analyzed IFN-γ-producing cells in liver mononuclear cells. Flow cytometric analysis showed significantly reduced IFN-γ production in hepatic NK and NKT cells in LECT2-deficient mice compared with in wild-type mice. We also demonstrated a decrease in IFN-γ production in LECT2-deficient mice after systemic administration of recombinant IL-12, which is known to induce IFN-γ in NK and NKT cells. These results indicate that a decrease of IFN-γ production in NK and NKT cells was involved in the alleviation of LPS/d-GalN-induced liver injury in LECT2-deficient mice.

Proteomic analysis of serum biomarkers for prediabetes using the Long-Evans Agouti rat, a spontaneous animal model of type 2 diabetes mellitus.

AIMS/INTRODUCTION: To identify candidate serum molecules associated with the progression of type 2 diabetes mellitus, differential serum proteomic analysis was carried out on a spontaneous animal model of type 2 diabetes mellitus without obesity, the Long-Evans Agouti (LEA) rat. MATERIALS AND METHODS: We carried out quantitative proteomic analysis using serum samples from 8- and 16-week-old LEA and control Brown Norway (BN) rats (n = 4/group). Differentially expressed proteins were validated by multiple reaction monitoring analysis using the sera collected from 8-, 16-, and 24-week-old LEA (n = 4/each group) and BN rats (n = 5/each group). Among the validated proteins, we also examined the possible relevance of the human homolog of serine protease inhibitor A3 (SERPINA3) to type 2 diabetes mellitus. RESULTS: The use of 2-D fluorescence difference gel electrophoresis analysis and the following liquid chromatography-multiple reaction monitoring analysis showed that the serum levels of five proteins were differentially changed between LEA rats and BN rats at all three time-points examined. Among the five proteins, SERPINA3N was increased significantly in the sera of LEA rats compared with age-matched BN rats. The serum level of SERPINA3 was also found to be significantly higher in type 2 diabetes mellitus patients than in healthy control participants. Furthermore, glycated hemoglobin, fasting insulin and estimated glomerular filtration rate were independently associated with the SERPINA3 levels. CONCLUSIONS: These findings suggest a possible role for SERPINA3 in the development of the early stages of type 2 diabetes mellitus, although further replication studies and functional investigations regarding their role are required.

The GCN5-CITED2-PKA signalling module controls hepatic glucose metabolism through a cAMP-induced substrate switch.

Hepatic gluconeogenesis during fasting results from gluconeogenic gene activation via the glucagon-cAMP-protein kinase A (PKA) pathway, a process whose dysregulation underlies fasting hyperglycemia in diabetes. Such transcriptional activation requires epigenetic changes at promoters by mechanisms that have remained unclear. Here we show that GCN5 functions both as a histone acetyltransferase (HAT) to activate fasting gluconeogenesis and as an acetyltransferase for the transcriptional co-activator PGC-1α to inhibit gluconeogenesis in the fed state. During fasting, PKA phosphorylates GCN5 in a manner dependent on the transcriptional coregulator CITED2, thereby increasing its acetyltransferase activity for histone and attenuating that for PGC-1α. This substrate switch concomitantly promotes both epigenetic changes associated with transcriptional activation and PGC-1α-mediated coactivation, thereby triggering gluconeogenesis. The GCN5-CITED2-PKA signalling module and associated GCN5 substrate switch thus serve as a key driver of gluconeogenesis. Disruption of this module ameliorates hyperglycemia in obese diabetic animals, offering a potential therapeutic strategy for such conditions.

Reduced serum level of leukocyte cell-derived chemotaxin 2 is associated with the presence of diabetic retinopathy.

BACKGROUND: Vascular endothelial growth factor (VEGF) signaling is an important pathway in the development of diabetic retinopathy (DR). A recent report showed that leukocyte cell-derived chemotaxin 2 (LECT2) suppresses the VEGF signaling in endothelial cells. However, the clinical relevance of LECT2 in DR is unknown. This study aimed to investigate serum LECT2 levels and the presence of DR. METHODS: The study included 230 people with type 2 diabetes mellitus (DM), 95 with DR and 135 without DR. Serum LECT2 levels were measured using an enzyme-linked immunosorbent assay. Data were evaluated using Spearman's rank correlation, univariate and multivariate logistic regression. RESULTS: Serum LECT2 levels were significantly lower in participants with DM having DR than in those not having DR (35.6±14.9ng/ml vs. 44.5±17.6ng/ml, P<0.001). Spearman's rank correlation analysis revealed a significant association between serum LECT2 levels and the presence of DR (P<0.001). Multiple regression analysis revealed that serum LECT2 levels were independently related to DR (P<0.001). CONCLUSIONS: These findings indicated that serum LECT2 level is negatively associated with the presence of DR and suggest that low circulating LECT2 level is a risk factor for DR.

Differential proteome analysis of serum proteins associated with the development of type 2 diabetes mellitus in the KK-A(y) mouse model using the iTRAQ technique.

To identify candidate serum molecules associated with the progression of type 2 diabetes mellitus (T2DM), we carried out differential proteomic analysis using the KK-A(y) mouse, an animal model of T2DM with obesity. We employed an iTRAQ-based quantitative proteomic approach to analyze the proteomic changes in the sera collected from a pair of 4-week-old KK-A(y) versus C57BL/6 mice. Among the 227 proteins identified, a total of 45 proteins were differentially expressed in KK-A(y) versus C57BL/6 mice. We comparatively analyzed a series of the sera collected at 4 and 12weeks of age from KK-A(y) and C57BL/6 mice for the target protein using multiple reaction monitoring analysis, and identified 8 differentially expressed proteins between the sera of these mice at both time points. Among them, serine (or cysteine) peptidase inhibitor, clade A, member 3K (SERPINA3K) levels were elevated significantly in the sera of KK-A(y) mice compared to C57BL/6 mice. An in vitro assay revealed that the human homologue SERPINA3 increased the transendothelial permeability of retinal microvascular endothelial cells, which may be involved in the pathogenesis of diabetes and/or diabetic retinopathy. With the identified proteins, our proteomics study could provide valuable clues for a better understanding of the underlying mechanisms associated with T2DM. BIOLOGICAL SIGNIFICANCE: In this paper, we investigated the serum proteome of KK-A(y) mice in a pre-diabetic state compared to that of wild type controls in an attempt to uncover early diagnostic markers of diabetes that are maintained through a diabetic phenotype. We used iTRAQ-based two-dimensional LC-MS/MS serum profiling, and identified several differentially expressed proteins at the pre-diabetic stage. The differential expression was confirmed by multiple reaction monitoring assay, which is fast gaining ground as a sensitive, specific, and cost-effective methodology for relative quantification of the candidate proteins. Using these techniques, we have identified eight candidate proteins of interest including SERPINA3K, which may be important in the pathology of T2DM and/or diabetic retinopathy.

Increased serum leukocyte cell-derived chemotaxin 2 (LECT2) levels in obesity and fatty liver.

Leukocyte cell-derived chemotaxin 2 (LECT2) is a signaling molecule expressed in the liver and regulated by Wnt/ß-catenin pathways implicated in hepatic metabolism. However, the clinical relevance of LECT2 in obesity and fatty liver is unknown. The objective of this study was to determine whether serum LECT2 levels are affected by of obesity and fatty liver. A cross sectional study comprising 231 Japanese adult subjects were tested for LECT2 using a highly sensitive assay. We evaluated the associations between LECT2 and the anthropometric or clinical markers of obesity and fatty liver. The mean serum LECT2 levels were 43.5 ± 13.6 ng/mL. LECT2 positively correlated with all the anthropometric measures of obesity: body mass index, waist circumference, waist-to-hip ratio, and waist-to-height ratio (W/Ht). Multiple regression analysis revealed that LECT2 is independently related to γ-glutamyl transpeptidase (γ-GTP), triglyceride, and age in males, whereas in females it was related to the homeostasis model assessment ratio, blood urea nitrogen, high-density lipoprotein cholesterol, and γ-GTP. Receiver operating characteristics curve analyses revealed that LECT2 correlated with obesity [area under the curve (AUC) 0.655, 95% confidence interval (CI) = 0.551-0.758, p = 0.002 in males; AUC 0.670, 95% CI = 0.570-0.770, p < 0.001 in females] and fatty liver (AUC 0.646, 95% CI = 0.544-0.749, p = 0.004 in males; AUC 0.733, 95% CI = 0.621-0.844, p < 0.001 in females). The present study indicates that serum LECT2 levels are increased by obesity and fatty liver, and suggests that LECT2 is a novel obesity-related protein.

Leukocyte cell-derived chemotaxin 2 is a zinc-binding protein.

Leukocyte cell-derived chemotaxin 2 (LECT2) is a secreted hepatic protein that has been associated with several physiological activities. LECT2 belongs to the peptidase M23 family, suggesting that it is a zinc-binding protein. To test this possibility, electrospray ionization mass spectrometry and X-ray absorption fine-structure analysis were performed. Results of these experiments indicated that recombinant mouse LECT2 produced by an animal cell line contains a zinc atom. Furthermore, the recombinant LECT2 was found to be self-oligomerized by disulfide bonds in vitro, but this was suppressed by addition of zinc. These results indicated that zinc stabilizes the LECT2 structure.

Pyridoxamine, an inhibitor of advanced glycation end product (AGE) formation ameliorates insulin resistance in obese, type 2 diabetic mice.

There is a growing body of evidence that the formation and accumulation of advanced glycation end products (AGE) have been known to progress under diabetic conditions, thereby being involved in diabetic vascular complications. Further, we, along with others, have recently found AGE could disturb insulin actions in cultured adipocytes and skeletal muscles. However, the pathological role of AGE in insulin resistance in vivo is not fully understood. Therefore, in this study, we examined whether pyridoxamine, an inhibitor of AGE formation could ameliorate insulin resistance in KK-A(y) mice, a model animal of obese, type 2 diabetes. Fasting blood glucose, serum levels of insulin and AGE in KK-A(y) mice were elevated as the mice got older (from 5 weeks old to 15 weeks old). Serum levels of AGE were positively correlated with insulin (R(2)=0.3956, P=0.002) in KK-A(y) mice. Administration of pyridoxamine dose-dependently decreased fasting insulin levels and improved insulin sensitivity in KK-A(y) mice of 10 weeks old, although it did not affect fasting blood glucose levels. Our present study suggests the involvement of AGE in insulin resistance in KK-A(y) mice. Inhibition of AGE formation may be a novel therapeutic target for improving insulin resistance in diabetes with obesity.