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Gut Microbes 2021is a butyrate-producing human gut symbiont that has been safely used as a probiotic for decades. strains have been investigated for potential protective or... (Review)
Review
is a butyrate-producing human gut symbiont that has been safely used as a probiotic for decades. strains have been investigated for potential protective or ameliorative effects in a wide range of human diseases, including gut-acquired infection, intestinal injury, irritable bowel syndrome, inflammatory bowel disease, neurodegenerative disease, metabolic disease, and colorectal cancer. In this review we summarize the studies on supplementation with special attention to proposed mechanisms for the associated health benefits and the supporting experimental evidence. These mechanisms center on molecular signals (especially butyrate) as well as immunological signals in the digestive system that cascade well beyond the gut to the liver, adipose tissue, brain, and more. The safety of probiotic strains appears well-established. We identify areas where additional human randomized controlled trials would provide valuable further data related to the strains' utility as an intervention.
Topics: Animals; Butyrates; Clostridium butyricum; Dietary Supplements; Host Microbial Interactions; Humans; Immunity; Inflammation; Irritable Bowel Syndrome; Metabolic Diseases; Neoplasms; Neurodegenerative Diseases; Probiotics; Symbiosis
PubMed: 33874858
DOI: 10.1080/19490976.2021.1907272 -
Signal Transduction and Targeted Therapy Mar 2023Epigenetics regulates gene expression and has been confirmed to play a critical role in a variety of metabolic diseases, such as diabetes, obesity, non-alcoholic fatty... (Review)
Review
Epigenetics regulates gene expression and has been confirmed to play a critical role in a variety of metabolic diseases, such as diabetes, obesity, non-alcoholic fatty liver disease (NAFLD), osteoporosis, gout, hyperthyroidism, hypothyroidism and others. The term 'epigenetics' was firstly proposed in 1942 and with the development of technologies, the exploration of epigenetics has made great progresses. There are four main epigenetic mechanisms, including DNA methylation, histone modification, chromatin remodelling, and noncoding RNA (ncRNA), which exert different effects on metabolic diseases. Genetic and non-genetic factors, including ageing, diet, and exercise, interact with epigenetics and jointly affect the formation of a phenotype. Understanding epigenetics could be applied to diagnosing and treating metabolic diseases in the clinic, including epigenetic biomarkers, epigenetic drugs, and epigenetic editing. In this review, we introduce the brief history of epigenetics as well as the milestone events since the proposal of the term 'epigenetics'. Moreover, we summarise the research methods of epigenetics and introduce four main general mechanisms of epigenetic modulation. Furthermore, we summarise epigenetic mechanisms in metabolic diseases and introduce the interaction between epigenetics and genetic or non-genetic factors. Finally, we introduce the clinical trials and applications of epigenetics in metabolic diseases.
Topics: Humans; Epigenesis, Genetic; Metabolic Diseases; DNA Methylation; Chromatin Assembly and Disassembly
PubMed: 36864020
DOI: 10.1038/s41392-023-01333-7 -
Cell Dec 2016Aging is the major risk factor for many human diseases. In vitro studies have demonstrated that cellular reprogramming to pluripotency reverses cellular age, but...
Aging is the major risk factor for many human diseases. In vitro studies have demonstrated that cellular reprogramming to pluripotency reverses cellular age, but alteration of the aging process through reprogramming has not been directly demonstrated in vivo. Here, we report that partial reprogramming by short-term cyclic expression of Oct4, Sox2, Klf4, and c-Myc (OSKM) ameliorates cellular and physiological hallmarks of aging and prolongs lifespan in a mouse model of premature aging. Similarly, expression of OSKM in vivo improves recovery from metabolic disease and muscle injury in older wild-type mice. The amelioration of age-associated phenotypes by epigenetic remodeling during cellular reprogramming highlights the role of epigenetic dysregulation as a driver of mammalian aging. Establishing in vivo platforms to modulate age-associated epigenetic marks may provide further insights into the biology of aging.
Topics: Aging; Aging, Premature; Animals; Cellular Reprogramming; Diabetes Mellitus, Type 2; Epigenesis, Genetic; Humans; Induced Pluripotent Stem Cells; Kruppel-Like Factor 4; Lamin Type A; Metabolic Diseases; Mice; Models, Animal; Pancreas; Sarcopenia; Transcription Factors
PubMed: 27984723
DOI: 10.1016/j.cell.2016.11.052 -
Cell Metabolism Jul 2021The bioactive sphingolipid metabolites ceramide and sphingosine-1-phosphate (S1P) are a recent addition to the lipids accumulated in obesity and have emerged as... (Review)
Review
The bioactive sphingolipid metabolites ceramide and sphingosine-1-phosphate (S1P) are a recent addition to the lipids accumulated in obesity and have emerged as important molecular players in metabolic diseases. Here we summarize evidence that dysregulation of sphingolipid metabolism correlates with pathogenesis of metabolic diseases in humans. This review discusses the current understanding of how ceramide regulates signaling and metabolic pathways to exacerbate metabolic diseases and the Janus faces for its further metabolite S1P, the kinases that produce it, and the multifaceted and at times opposing actions of S1P receptors in various tissues. Gaps and limitations in current knowledge are highlighted together with the need to further decipher the full array of their actions in tissue dysfunction underlying metabolic pathologies, pointing out prospects to move this young field of research toward the development of effective therapeutics.
Topics: Animals; Humans; Lipid Metabolism; Metabolic Diseases; Metabolic Networks and Pathways; Obesity; Sphingolipids
PubMed: 34233172
DOI: 10.1016/j.cmet.2021.06.006 -
Frontiers in Immunology 2020The gut microbiota has been linked to the development of obesity and type 2 diabetes (T2D). The underlying mechanisms as to how intestinal microbiota may contribute to... (Review)
Review
The gut microbiota has been linked to the development of obesity and type 2 diabetes (T2D). The underlying mechanisms as to how intestinal microbiota may contribute to T2D are only partly understood. It becomes progressively clear that T2D is characterized by a chronic state of low-grade inflammation, which has been linked to the development of insulin resistance. Here, we review the current evidence that intestinal microbiota, and the metabolites they produce, could drive the development of insulin resistance in obesity and T2D, possibly by initiating an inflammatory response. First, we will summarize major findings about immunological and gut microbial changes in these metabolic diseases. Next, we will give a detailed view on how gut microbial changes have been implicated in low-grade inflammation. Lastly, we will critically discuss clinical studies that focus on the interaction between gut microbiota and the immune system in metabolic disease. Overall, there is strong evidence that the tripartite interaction between gut microbiota, host immune system and metabolism is a critical partaker in the pathophysiology of obesity and T2D.
Topics: Animals; Diabetes Mellitus, Type 2; Gastrointestinal Microbiome; Humans; Inflammation; Insulin Resistance; Metabolic Diseases; Obesity
PubMed: 33178196
DOI: 10.3389/fimmu.2020.571731 -
Biological Reviews of the Cambridge... Aug 2015The pentose phosphate pathway (PPP) is a fundamental component of cellular metabolism. The PPP is important to maintain carbon homoeostasis, to provide precursors for... (Review)
Review
The pentose phosphate pathway (PPP) is a fundamental component of cellular metabolism. The PPP is important to maintain carbon homoeostasis, to provide precursors for nucleotide and amino acid biosynthesis, to provide reducing molecules for anabolism, and to defeat oxidative stress. The PPP shares reactions with the Entner-Doudoroff pathway and Calvin cycle and divides into an oxidative and non-oxidative branch. The oxidative branch is highly active in most eukaryotes and converts glucose 6-phosphate into carbon dioxide, ribulose 5-phosphate and NADPH. The latter function is critical to maintain redox balance under stress situations, when cells proliferate rapidly, in ageing, and for the 'Warburg effect' of cancer cells. The non-oxidative branch instead is virtually ubiquitous, and metabolizes the glycolytic intermediates fructose 6-phosphate and glyceraldehyde 3-phosphate as well as sedoheptulose sugars, yielding ribose 5-phosphate for the synthesis of nucleic acids and sugar phosphate precursors for the synthesis of amino acids. Whereas the oxidative PPP is considered unidirectional, the non-oxidative branch can supply glycolysis with intermediates derived from ribose 5-phosphate and vice versa, depending on the biochemical demand. These functions require dynamic regulation of the PPP pathway that is achieved through hierarchical interactions between transcriptome, proteome and metabolome. Consequently, the biochemistry and regulation of this pathway, while still unresolved in many cases, are archetypal for the dynamics of the metabolic network of the cell. In this comprehensive article we review seminal work that led to the discovery and description of the pathway that date back now for 80 years, and address recent results about genetic and metabolic mechanisms that regulate its activity. These biochemical principles are discussed in the context of PPP deficiencies causing metabolic disease and the role of this pathway in biotechnology, bacterial and parasite infections, neurons, stem cell potency and cancer metabolism.
Topics: Humans; Metabolic Diseases; Metabolism; Pentose Phosphate Pathway
PubMed: 25243985
DOI: 10.1111/brv.12140 -
Frontiers in Endocrinology 2023Insulin resistance (IR) plays a crucial role in the development and progression of metabolism-related diseases such as diabetes, hypertension, tumors, and nonalcoholic...
Insulin resistance (IR) plays a crucial role in the development and progression of metabolism-related diseases such as diabetes, hypertension, tumors, and nonalcoholic fatty liver disease, and provides the basis for a common understanding of these chronic diseases. In this study, we provide a systematic review of the causes, mechanisms, and treatments of IR. The pathogenesis of IR depends on genetics, obesity, age, disease, and drug effects. Mechanistically, any factor leading to abnormalities in the insulin signaling pathway leads to the development of IR in the host, including insulin receptor abnormalities, disturbances in the internal environment (regarding inflammation, hypoxia, lipotoxicity, and immunity), metabolic function of the liver and organelles, and other abnormalities. The available therapeutic strategies for IR are mainly exercise and dietary habit improvement, and chemotherapy based on biguanides and glucagon-like peptide-1, and traditional Chinese medicine treatments (e.g., herbs and acupuncture) can also be helpful. Based on the current understanding of IR mechanisms, there are still some vacancies to follow up and consider, and there is also a need to define more precise biomarkers for different chronic diseases and lifestyle interventions, and to explore natural or synthetic drugs targeting IR treatment. This could enable the treatment of patients with multiple combined metabolic diseases, with the aim of treating the disease holistically to reduce healthcare expenditures and to improve the quality of life of patients to some extent.
Topics: Insulin Resistance; Humans; Chronic Disease; Signal Transduction; Metabolic Diseases; Receptor, Insulin
PubMed: 37056675
DOI: 10.3389/fendo.2023.1149239 -
Pharmacological Reviews Oct 2014Bile acids are the end products of cholesterol catabolism. Hepatic bile acid synthesis accounts for a major fraction of daily cholesterol turnover in humans. Biliary... (Review)
Review
Bile acids are the end products of cholesterol catabolism. Hepatic bile acid synthesis accounts for a major fraction of daily cholesterol turnover in humans. Biliary secretion of bile acids generates bile flow and facilitates hepatobiliary secretion of lipids, lipophilic metabolites, and xenobiotics. In the intestine, bile acids are essential for the absorption, transport, and metabolism of dietary fats and lipid-soluble vitamins. Extensive research in the last 2 decades has unveiled new functions of bile acids as signaling molecules and metabolic integrators. The bile acid-activated nuclear receptors farnesoid X receptor, pregnane X receptor, constitutive androstane receptor, vitamin D receptor, and G protein-coupled bile acid receptor play critical roles in the regulation of lipid, glucose, and energy metabolism, inflammation, and drug metabolism and detoxification. Bile acid synthesis exhibits a strong diurnal rhythm, which is entrained by fasting and refeeding as well as nutrient status and plays an important role for maintaining metabolic homeostasis. Recent research revealed an interaction of liver bile acids and gut microbiota in the regulation of liver metabolism. Circadian disturbance and altered gut microbiota contribute to the pathogenesis of liver diseases, inflammatory bowel diseases, nonalcoholic fatty liver disease, diabetes, and obesity. Bile acids and their derivatives are potential therapeutic agents for treating metabolic diseases of the liver.
Topics: Animals; Bile Acids and Salts; Circadian Rhythm; Glucose; Humans; Lipid Metabolism; Liver; Metabolic Diseases; MicroRNAs; Microbiota; Models, Biological; Receptors, G-Protein-Coupled; Signal Transduction
PubMed: 25073467
DOI: 10.1124/pr.113.008201 -
Circulation Mar 2018The prevalence of obesity has increased globally over the last 2 decades. Although the body mass index has been a convenient and simple index of obesity at the... (Review)
Review
The prevalence of obesity has increased globally over the last 2 decades. Although the body mass index has been a convenient and simple index of obesity at the population level, studies have shown that obesity defined by body mass index alone is a remarkably heterogeneous condition with varying cardiovascular and metabolic manifestations across individuals. Adipose tissue is an exquisitely active metabolic organ engaged in cross-talk between various systems; perturbation of adipose tissue results in a pathological response to positive caloric balance in susceptible individuals that directly and indirectly contributes to cardiovascular and metabolic disease. Inadequate subcutaneous adipose tissue expansion in the face of dietary triglycerides leads to visceral and ectopic fat deposition, inflammatory/adipokine dysregulation, and insulin resistance. Conversely, preferential fat storage in the lower body depot may act as a metabolic buffer and protect other tissues from lipotoxicity caused by lipid overflow and ectopic fat. Translational, epidemiological, and clinical studies over the past 30 years have clearly demonstrated a strong link between visceral and ectopic fat and the development of a clinical syndrome characterized by atherogenic dyslipidemia, hyperinsulinemia/glucose intolerance, hypertension, atherosclerosis, and adverse cardiac remodeling/heart failure. This relationship is even more nuanced when clinical entities such as metabolically healthy obesity phenotype and the obesity paradox are considered. Although it is clear that the accumulation of visceral/ectopic fat is a major contributor to cardiovascular and metabolic risk above and beyond the body mass index, implementation of fat distribution assessment into clinical practice remains a challenge. Anthropometric indexes of obesity are easily implemented, but newer imaging-based methods offer improved sensitivity and specificity for measuring specific depots. Lifestyle, pharmacological, and surgical interventions allow a multidisciplinary approach to overweight/obesity that may improve outcomes and align with a public health message to combat the growing epidemic of obesity worldwide and to build healthier lives free of cardiovascular diseases.
Topics: Adipose Tissue; Adiposity; Appetite Depressants; Body Mass Index; Cardiovascular Diseases; Humans; Metabolic Diseases; Obesity; Risk Factors
PubMed: 29581366
DOI: 10.1161/CIRCULATIONAHA.117.029617 -
Circulation Research Sep 2018The sirtuin family of nicotinamide adenine dinucleotide-dependent deacylases (SIRT1-7) are thought to be responsible, in large part, for the cardiometabolic benefits of... (Review)
Review
The sirtuin family of nicotinamide adenine dinucleotide-dependent deacylases (SIRT1-7) are thought to be responsible, in large part, for the cardiometabolic benefits of lean diets and exercise and when upregulated can delay key aspects of aging. SIRT1, for example, protects against a decline in vascular endothelial function, metabolic syndrome, ischemia-reperfusion injury, obesity, and cardiomyopathy, and SIRT3 is protective against dyslipidemia and ischemia-reperfusion injury. With increasing age, however, nicotinamide adenine dinucleotide levels and sirtuin activity steadily decrease, and the decline is further exacerbated by obesity and sedentary lifestyles. Activation of sirtuins or nicotinamide adenine dinucleotide repletion induces angiogenesis, insulin sensitivity, and other health benefits in a wide range of age-related cardiovascular and metabolic disease models. Human clinical trials testing agents that activate SIRT1 or boost nicotinamide adenine dinucleotide levels are in progress and show promise in their ability to improve the health of cardiovascular and metabolic disease patients.
Topics: Age Factors; Aging; Animals; Cardiovascular Diseases; Cardiovascular System; Enzyme Activation; Enzyme Activators; Humans; Metabolic Diseases; NAD; Sirtuins; Up-Regulation
PubMed: 30355082
DOI: 10.1161/CIRCRESAHA.118.312498