Proteomic profiling of skeletal muscle tissue from the Goto-Kakizaki rat model of type 2 diabetes.

The primary features of type 2 diabetes (T2D) are both insulin resistance and impaired beta cell function. Abnormal glucose handling and variable degrees of peripheral insulin resistance characterise T2D. Skeletal muscle is the largest insulin-regulated glucose sink in the body and represents approximately 80% of whole body insulin-stimulated glucose uptake. As a result a fundamental aspect of T2D is abnormal glucose disposal in contractile tissues triggering metabolic dysregulation and glucotoxic side effects. The significance of skeletal muscle to T2D has prompted research into the perturbed glucose handling mechanisms in suitable animal models, such as muscle tissues from the spontaneously diabetic Goto-Kakizaki rat. Highly sensitive protein analysis techniques such as fluorescence difference in-gel electrophoresis (DIGE) and electrospray ionization liquid chromatography mass spectrometry (ESI LC/MS) were employed to analysis the diabetic muscle tissue proteome and sub-proteome. A differential expression pattern was observed for proteins involved in glycolysis, the citric acid cycle, oxidative phosphorylation, lipolytic catabolism, the contractile apparatus, cellular detoxification mechanisms and the stress response. These findings demonstrate a perturbed protein expression pattern in diabetic skeletal muscle, which reflects underlying molecular alterations. Over all this study has supplied several potential biomarkers of T2D and adds further knowledge to the mechanism of a complex metabolic disorder

Proteomic analysis of the mitochondria-enriched fraction from diabetic rat skeletal muscle

Mitochondrial dysfunction in muscle has been implicated to play a causative role or being an indirect consequence of insulin resistance in type-2 diabetes. In order to investigate potential diabetes-related alterations in the mitochondrial proteome of muscle, we have carried out a mass spectrometry-based proteomic analysis of the gastrocnemius muscle from normal versus diabetic Goto-Kakizaki rats. A generally perturbed protein expression pattern was observed in the mitochondria-enriched fraction from diabetic muscle. Various mitochondrial markers, including NADH dehydrogenase, cytochrome b-c1 complex and isocitrate dehydrogenase were reduced in diabetic preparations. Isoforms of pyruvate dehydrogenase and ATP synthase exhibited differential changes in their abundance. The altered protein expression levels of these key metabolic enzymes might trigger a diabetes-dependent decrease in mitochondrial oxidative phosphorylation levels. The proteomic findings presented here support the idea that mitochondrial abnormalities are involved in the molecular pathogenesis of type-2 diabetes and may be crucial for the development of insulin resistance

Skeletal muscle tissue from the Goto-Kakizaki rat model of type-2 diabetes exhibits increased levels of the small heat shock protein Hsp27

In order to increase our understanding of diabetes-related muscle weakness, we carried out a mass spectrometry-based proteomic analysis of skeletal muscle preparations from the Goto-Kakizaki rat model of type-2 diabetes. Fluorescence difference in-gel electrophoresis was performed to determine potential differences in the global protein expression profile of muscle extracts. Besides changes in contractile proteins and metabolic enzymes, the abundance of the small stress proteins αB-crystallin and Hsp27 was significantly increased. The up-regulation of the low-molecular-mass heat shock protein Hsp27 was confirmed by an alternative fluorescent staining method of two-dimensional gels and immunoblotting. The observed protein alterations in the cellular stress response, distinct metabolic pathways, regulatory mechanisms and the contractile apparatus might be directly or indirectly associated with peripheral resistance to insulin signalling, making these newly identified muscle proteins potential biomarkers of type-2 diabetes. Increased levels of molecular chaperones suggest considerably enhanced cellular stress levels in diabetic muscle fibres

Skeletal muscle tissue from the Goto-Kakizaki rat model of type-2 diabetes exhibits increased levels of the small heat shock protein Hsp27

In order to increase our understanding of diabetes-related muscle weakness, we carried out a mass spectrometry-based proteomic analysis of skeletal muscle preparations from the Goto-Kakizaki rat model of type-2 diabetes. Fluorescence difference in-gel electrophoresis was performed to determine potential differences in the global protein expression profile of muscle extracts. Besides changes in contractile proteins and metabolic enzymes, the abundance of the small stress proteins αB-crystallin and Hsp27 was significantly increased. The up-regulation of the low-molecular-mass heat shock protein Hsp27 was confirmed by an alternative fluorescent staining method of two-dimensional gels and immunoblotting. The observed protein alterations in the cellular stress response, distinct metabolic pathways, regulatory mechanisms and the contractile apparatus might be directly or indirectly associated with peripheral resistance to insulin signalling, making these newly identified muscle proteins potential biomarkers of type-2 diabetes. Increased levels of molecular chaperones suggest considerably enhanced cellular stress levels in diabetic muscle fibres

DIGE analysis of rat skeletal muscle proteins using nonionic detergent phase extraction of young adult versus aged gastrocnemius tissue

Contractile weakness and loss of muscle mass are critical features of the aging process in mammalians. Age-related fibre wasting has a profound effect on muscle metabolism, fibre type distribution and the overall physiological integrity of the neuromuscular system. This study has used mass spectrometry-based proteomics to investigate the fate of the aging rat muscle proteome. Using nonionic detergent phase extraction, this report shows that the aged gastrocnemius muscle exhibits a generally perturbed protein expression pattern in both the detergent-extracted fraction and the aqueous protein complement from senescent muscle tissue. In the detergent-extracted fraction, the expression of ATP synthase, isocitrate dehydrogenase, enolase, tropomyosin and beta-actin was increased. Different isoforms of creatine kinase and prohibitin showed differential changes. In the aqueous fraction, malate dehydrogenase, sulfotransferase, triosephosphate isomerase, aldolase, cofilin-2 and lactate dehydrogenase showed increased levels. Interestingly, differential effects on dissimilar 2-D spots of the same protein species were shown for Cu/Zn superoxide dismutase, albumin, annexin A4 and phosphoglycolate phosphatase. Mitochondrial Hsp60, Hsp71 and nucleoside diphosphate kinase B exhibited a reduced abundance in aged muscle. The majority of altered proteins were found to be involved in mitochondrial metabolism, glycolysis, metabolic transportation, regulatory processes, the cellular stress response, detoxification mechanisms and muscle contraction

Breast cancer management pathways during the COVID-19 pandemic: outcomes from the UK ‘Alert Level 4’ phase of the B-MaP-C study

Abstract: Background: The B-MaP-C study aimed to determine alterations to breast cancer (BC) management during the peak transmission period of the UK COVID-19 pandemic and the potential impact of these treatment decisions. Methods: This was a national cohort study of patients with early BC undergoing multidisciplinary team (MDT)-guided treatment recommendations during the pandemic, designated ‘standard’ or ‘COVID-altered’, in the preoperative, operative and post-operative setting. Findings: Of 3776 patients (from 64 UK units) in the study, 2246 (59%) had ‘COVID-altered’ management. ‘Bridging’ endocrine therapy was used (n = 951) where theatre capacity was reduced. There was increasing access to COVID-19 low-risk theatres during the study period (59%). In line with national guidance, immediate breast reconstruction was avoided (n = 299). Where adjuvant chemotherapy was omitted (n = 81), the median benefit was only 3% (IQR 2–9%) using ‘NHS Predict’. There was the rapid adoption of new evidence-based hypofractionated radiotherapy (n = 781, from 46 units). Only 14 patients (1%) tested positive for SARS-CoV-2 during their treatment journey. Conclusions: The majority of ‘COVID-altered’ management decisions were largely in line with pre-COVID evidence-based guidelines, implying that breast cancer survival outcomes are unlikely to be negatively impacted by the pandemic. However, in this study, the potential impact of delays to BC presentation or diagnosis remains unknown

Proteomic profiling of skeletal muscle tissue from the Goto-Kakizaki rat model of type 2 diabetes.

The primary features of type 2 diabetes (T2D) are both insulin resistance and impaired beta cell function. Abnormal glucose handling and variable degrees of peripheral insulin resistance characterise T2D. Skeletal muscle is the largest insulin-regulated glucose sink in the body and represents approximately 80% of whole body insulin-stimulated glucose uptake. As a result a fundamental aspect of T2D is abnormal glucose disposal in contractile tissues triggering metabolic dysregulation and glucotoxic side effects. The significance of skeletal muscle to T2D has prompted research into the perturbed glucose handling mechanisms in suitable animal models, such as muscle tissues from the spontaneously diabetic Goto-Kakizaki rat. Highly sensitive protein analysis techniques such as fluorescence difference in-gel electrophoresis (DIGE) and electrospray ionization liquid chromatography mass spectrometry (ESI LC/MS) were employed to analysis the diabetic muscle tissue proteome and sub-proteome. A differential expression pattern was observed for proteins involved in glycolysis, the citric acid cycle, oxidative phosphorylation, lipolytic catabolism, the contractile apparatus, cellular detoxification mechanisms and the stress response. These findings demonstrate a perturbed protein expression pattern in diabetic skeletal muscle, which reflects underlying molecular alterations. Over all this study has supplied several potential biomarkers of T2D and adds further knowledge to the mechanism of a complex metabolic disorder

Proteomic profiling of skeletal muscle tissue from the Goto-Kakizaki rat model of type 2 diabetes.

The primary features of type 2 diabetes (T2D) are both insulin resistance and impaired beta cell function. Abnormal glucose handling and variable degrees of peripheral insulin resistance characterise T2D. Skeletal muscle is the largest insulin-regulated glucose sink in the body and represents approximately 80% of whole body insulin-stimulated glucose uptake. As a result a fundamental aspect of T2D is abnormal glucose disposal in contractile tissues triggering metabolic dysregulation and glucotoxic side effects. The significance of skeletal muscle to T2D has prompted research into the perturbed glucose handling mechanisms in suitable animal models, such as muscle tissues from the spontaneously diabetic Goto-Kakizaki rat. Highly sensitive protein analysis techniques such as fluorescence difference in-gel electrophoresis (DIGE) and electrospray ionization liquid chromatography mass spectrometry (ESI LC/MS) were employed to analysis the diabetic muscle tissue proteome and sub-proteome. A differential expression pattern was observed for proteins involved in glycolysis, the citric acid cycle, oxidative phosphorylation, lipolytic catabolism, the contractile apparatus, cellular detoxification mechanisms and the stress response. These findings demonstrate a perturbed protein expression pattern in diabetic skeletal muscle, which reflects underlying molecular alterations. Over all this study has supplied several potential biomarkers of T2D and adds further knowledge to the mechanism of a complex metabolic disorder

Proteomic profiling of skeletal muscle tissue from the Goto-Kakizaki rat model of type 2 diabetes.

The primary features of type 2 diabetes (T2D) are both insulin resistance and impaired beta cell function. Abnormal glucose handling and variable degrees of peripheral insulin resistance characterise T2D. Skeletal muscle is the largest insulin-regulated glucose sink in the body and represents approximately 80% of whole body insulin-stimulated glucose uptake. As a result a fundamental aspect of T2D is abnormal glucose disposal in contractile tissues triggering metabolic dysregulation and glucotoxic side effects. The significance of skeletal muscle to T2D has prompted research into the perturbed glucose handling mechanisms in suitable animal models, such as muscle tissues from the spontaneously diabetic Goto-Kakizaki rat. Highly sensitive protein analysis techniques such as fluorescence difference in-gel electrophoresis (DIGE) and electrospray ionization liquid chromatography mass spectrometry (ESI LC/MS) were employed to analysis the diabetic muscle tissue proteome and sub-proteome. A differential expression pattern was observed for proteins involved in glycolysis, the citric acid cycle, oxidative phosphorylation, lipolytic catabolism, the contractile apparatus, cellular detoxification mechanisms and the stress response. These findings demonstrate a perturbed protein expression pattern in diabetic skeletal muscle, which reflects underlying molecular alterations. Over all this study has supplied several potential biomarkers of T2D and adds further knowledge to the mechanism of a complex metabolic disorder

Proteomic profiling of skeletal muscle tissue from the Goto-Kakizaki rat model of type 2 diabetes.

The primary features of type 2 diabetes (T2D) are both insulin resistance and impaired beta cell function. Abnormal glucose handling and variable degrees of peripheral insulin resistance characterise T2D. Skeletal muscle is the largest insulin-regulated glucose sink in the body and represents approximately 80% of whole body insulin-stimulated glucose uptake. As a result a fundamental aspect of T2D is abnormal glucose disposal in contractile tissues triggering metabolic dysregulation and glucotoxic side effects. The significance of skeletal muscle to T2D has prompted research into the perturbed glucose handling mechanisms in suitable animal models, such as muscle tissues from the spontaneously diabetic Goto-Kakizaki rat. Highly sensitive protein analysis techniques such as fluorescence difference in-gel electrophoresis (DIGE) and electrospray ionization liquid chromatography mass spectrometry (ESI LC/MS) were employed to analysis the diabetic muscle tissue proteome and sub-proteome. A differential expression pattern was observed for proteins involved in glycolysis, the citric acid cycle, oxidative phosphorylation, lipolytic catabolism, the contractile apparatus, cellular detoxification mechanisms and the stress response. These findings demonstrate a perturbed protein expression pattern in diabetic skeletal muscle, which reflects underlying molecular alterations. Over all this study has supplied several potential biomarkers of T2D and adds further knowledge to the mechanism of a complex metabolic disorder