Aerobic Exercise Modulates Proteomic Profiles in Gastrocnemius Muscle of db/db Mice, Ameliorating Sarcopenia.

Type-2 diabetes mellitus (T2DM)-induced sarcopenia is intertwined with diminished insulin sensitivity and extracellular matrix (ECM) remodeling in skeletal muscle and other organs. Physical activities such as aerobic exercise play a crucial role in regulating blood glucose levels, insulin sensitivity, metabolic pathways, oxidative stress, fibrosis, ECM remodeling, and muscle regeneration by modulating differentially expressed protein (DEP) levels. The objectives of our research were to investigate the effect of six weeks of aerobic exercise on the gastrocnemius and soleus muscle of db/db mice's DEP levels compared to those of sedentary db/db mice. A total of eight db/db mice were divided into two groups (n = 4 per group), namely sedentary mice (SED) and exercise-trained mice (ET), of which the latter were subjected to six weeks of a moderate-intensity aerobic exercise intervention for five days per week. After the exercise intervention, biochemical tests, including analyses of blood glucose and HbA1c levels, were performed. Histological analysis using H & E staining on tissue was performed to compare morphological characters. Gastrocnemius and soleus muscles were dissected and processed for proteomic analysis. Data were provided and analyzed based on the DEPs using the label-free quantification (LFQ) algorithm. Functional enrichment analysis and Ingenuity Pathway Analysis (IPA) were employed as bioinformatics tools to elucidate the molecular mechanisms involved in the DEPs and disease progression. Significantly reduced blood glucose and HbA1c levels and an increased cross-sectional area (CSA) of gastrocnemius muscle fibers were seen in the ET group after the exercise interventions due to upregulations of metabolic pathways. Using proteomics data analysis, we found a significant decrease in COL1A1, COL4A2, ENG, and LAMA4 protein levels in the ET gastrocnemius, showing a significant improvement in fibrosis recovery, ECM remodeling, and muscle regeneration via the downregulation of the TGF-ß signaling pathway. Upregulated metabolic pathways due to ET-regulated DEPs in the gastrocnemius indicated increased glucose metabolism, lipid metabolism, muscle regeneration, and insulin sensitivity, which play a crucial role in muscle regeneration and maintaining blood glucose and lipid levels. No significant changes were observed in the soleus muscle due to the type of exercise and muscle fiber composition. Our research suggests that engaging in six weeks of aerobic exercise may have a positive impact on the recovery of T2DM-induced sarcopenia, which might be a potential candidate for mitigation, prevention, and therapeutic treatment in the future.

A comprehensive bibliometric analysis of global research on the role of acrolein in Alzheimer's disease pathogenesis: involvement of amyloid-beta.

Background: Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive and behavioral decline. Acrolein, an environmental pollutant and endogenous compound, is implicated in AD development. This research employs bibliometric analysis to assess current trends and key areas concerning acrolein-AD interaction. Methods: The Web of Science was used to extensively review literature on acrolein and AD. Relevant data were systematically gathered and analyzed using VOSviewer, CiteSpace, and an online bibliometric tool. Results: We identified 120 English publications in this specialized field across 19 journals. The Journal of Alzheimer's Disease was the most prominent. The primary contributors, both in terms of scientific output and influence, were the USA, the University of Kentucky, and Ramassamy C, representing countries/regions, institutions, and authors, respectively. In this field, the primary focus was on thoroughly studying acrolein, its roles, and its mechanisms in AD utilizing both in vivo and in vitro approaches. A significant portion of the research was based on proteomics, revealing complex molecular processes. The main focuses in the field were "oxidative stress," "lipid peroxidation," "amyloid-beta," and "cognitive impairment." Anticipated future research trajectories focus on the involvement of the internalization pathway, covering key areas such as synaptic dysfunction, metabolism, mechanisms, associations, neuroinflammation, inhibitors, tau phosphorylation, acrolein toxicity, brain infarction, antioxidants, chemistry, drug delivery, and dementia. Our analysis also supported our previous hypothesis that acrolein can interact with amyloid-beta to form a protein adduct leading to AD-like pathology and altering natural immune responses. Conclusion: This study provides a broad and all-encompassing view of the topic, offering valuable insights and guidance to fellow researchers. These emerging directions underscore the continuous exploration of the complexities associated with AD. The analyses and findings aim to enhance our understanding of the intricate relationship between acrolein and AD for future research.

Acrolein adducts and responding autoantibodies correlate with metabolic disturbance in Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD) is caused by many intertwining pathologies involving metabolic aberrations. Patients with metabolic syndrome (MetS) generally show hyperglycemia and dyslipidemia, which can lead to the formation of aldehydic adducts such as acrolein on peptides in the brain and blood. However, the pathogenesis from MetS to AD remains elusive. METHODS: An AD cell model expressing Swedish and Indiana amyloid precursor protein (APP-Swe/Ind) in neuro-2a cells and a 3xTg-AD mouse model were used. Human serum samples (142 control and 117 AD) and related clinical data were collected. Due to the involvement of MetS in AD, human samples were grouped into healthy control (HC), MetS-like, AD with normal metabolism (AD-N), and AD with metabolic disturbance (AD-M). APP, amyloid-beta (Aß), and acrolein adducts in the samples were analyzed using immunofluorescent microscopy, histochemistry, immunoprecipitation, immunoblotting, and/or ELISA. Synthetic Aß1-16 and Aß17-28 peptides were modified with acrolein in vitro and verified using LC-MS/MS. Native and acrolein-modified Aß peptides were used to measure the levels of specific autoantibodies IgG and IgM in the serum. The correlations and diagnostic power of potential biomarkers were evaluated. RESULTS: An increased level of acrolein adducts was detected in the AD model cells. Furthermore, acrolein adducts were observed on APP C-terminal fragments (APP-CTFs) containing Aß in 3xTg-AD mouse serum, brain lysates, and human serum. The level of acrolein adducts was correlated positively with fasting glucose and triglycerides and negatively with high-density lipoprotein-cholesterol, which correspond with MetS conditions. Among the four groups of human samples, the level of acrolein adducts was largely increased only in AD-M compared to all other groups. Notably, anti-acrolein-Aß autoantibodies, especially IgM, were largely reduced in AD-M compared to the MetS group, suggesting that the specific antibodies against acrolein adducts may be depleted during pathogenesis from MetS to AD. CONCLUSIONS: Metabolic disturbance may induce acrolein adduction, however, neutralized by responding autoantibodies. AD may be developed from MetS when these autoantibodies are depleted. Acrolein adducts and the responding autoantibodies may be potential biomarkers for not only diagnosis but also immunotherapy of AD, especially in complication with MetS.

Reduction of AHI1 in the serum of Taiwanese with probable Alzheimer's disease.

OBJECTIVE: The development of blood-based biomarkers for early diagnosis and treatment of Alzheimer's disease (AD) is desirable. In AD model mouse brain and neuronal cells, Abelson helper integration site-1 (AHI1) protein is reduced. AHI1 facilitates intracellular amyloid precursor protein (APP) translocation to inhibit amyloidogenic pathology of AD, and thus may be an AD biomarker. METHODS: This study was conducted among 32 AD patients and 54 healthy control (HC) subjects. AHI1-related protein levels from initially collected serum samples in each group were screened using Western blotting. The protein concentrations of AHI1 and amyloid-ß (Aß), peptide(s) derived from APP, from all serum samples were analyzed using ELISA. RESULTS: In AD serum, AHI1 and a large truncated C-terminal APP fragment were significantly reduced. The average concentrations of serum AHI1 and Aß in AD were significantly lower than those in HC. Notably, AHI1 concentration in HC serum was decreased in an age-dependent manner, while it was consistently low in AD serum and had no correlation with Aß or mini-mental state examination score. The receiver operating characteristic analysis on all subjects demonstrated an area under curve (AUC) value of 0.7 for AHI1 on AD diagnosis, while the AUC increased to 0.82 on the subjects younger than 77 years old, suggesting a good diagnostic performance of serum AHI1 for AD especially at relatively young age. CONCLUSION: An early event of AHI1 reduction in the body of AD patients was observed. Serum AHI1 may be valuable for early diagnosis of AD.