The pathogenic role of persistent milk signaling in mTORC1- and milk-microRNA-driven type 2 diabetes mellitus

The effect of miR-23b-3p on regulating GH by targeting POU1F1 in Yanbian yellow cattle

This study aimed to evaluate the effect of miR-23b-3p on growth hormone (GH) in pituitary cells of Yanbian yellow cattle. The mRNA and protein levels of GH and miR-23b-3p target genes were measured by real time fluorescence quantitative PCR (qPCR) and Western blot, respectively. The target relationship of miR-23b-3p was validated by double luciferase reporter gene system. The results showed that GH mRNA and protein levels in pituitary cells of Yanbian yellow cattle were significantly lower in the miR-23b-3p-mi group than in the NC group (P<0.01), while GH mRNA and protein levels were higher in the miR-23b-3p-in group than in the iNC group (P<0.05). The result of bioinformatics analysis and double luciferase reporter gene system validation proved that miR-23b-3p targeted 3'UTR of pituitary specific transcription factor 1 (POU1F1). POU1F1 mRNA and protein levels were lower miR-23b-3p-mi group than in the NC group (P<0.01), while POU1F1 mRNA and protein levels were higher in the miR-23b-3p-in group than in the iNC group (P<0.01). These results demonstrated that miR-23b-3p could regulate GH expression in pituitary cells by regulating POU1F1 gene.

A Study of FoxO1, mTOR, miR-21, miR-29b, and miR-98 Expression Levels Regarding Metabolic Syndrome in Acne Vulgaris Patients

BACKGROUND

Acne vulgaris (AV) is an inflammatory skin disease caused by the mechanistic target of rapamycin complex 1 (mTORC1). forkhead box protein (Fox) O1 is known to regulate the relationship between the mTORC1 signaling pathway and insulin resistance (IR). Increased mTORC1 signaling is known to predispose one to diseases such as insulin resistance (IR), obesity, and diabetes mellitus. One of the major components of mTORC1 is mTOR. FoxO1 and mTOR play key roles in the onset and progression of metabolic syndrome (MetS). In this study, we aimed to elucidate the relationship between AV and MetS through FoxO1 and mTOR signaling pathways and microRNAs (miRs) associated with these signaling pathways.

METHODS

We examined 20 AV patients without MetS, 16 AV patients with MetS, and 20 healthy controls. The demographic characteristics of the patients, MetS parameters, clinical severity of AV (Global Acne Grading System, GAGS), and the homeostasis model assessment (HOMA) values were compared between the groups. In addition, the expression levels of FoxO1 and mTOR genes, along with the expression levels of miR-21, miR-29b, and miR-98, were assessed in skin biopsy samples from all groups using real-time polymerase chain reaction methods. FoxO1, mTOR, and miRNA expression levels were recorded as fold change.

RESULTS

The mean age of patients with AV without MetS was statistically lower. In AV patients with MetS, those with moderate GAGS scores had statistically significantly higher HOMA values than those with mild GAGS scores. FoxO1 expression was significantly lower in AV patients compared to controls. The mTOR expression levels of AV patients with MetS were significantly higher than the other two groups. The expression levels of miR-21 and miR-29b were significantly increased in the group of AV patients with MetS compared to the group of AV patients without MetS.

CONCLUSIONS

These results suggested that the mTOR pathway may play an important role in explaining the relationship between AV and MetS in acne pathogenesis. They also suggested that miR-21 and miR-29b play a role in the inflammatory process of AV.

Pasteurization of human milk affects the miRNA cargo of EVs decreasing its immunomodulatory activity

In this report, we evaluated the effect of the pasteurization (P) process of mother's own milk (MOM) on the miRNA content of extracellular vesicles (EVs) and its impact on innate immune responses. Differences in size or particle number were not observed upon pasteurization of MOM (PMOM). However, significant differences were observed in the EV membrane marker CD63 and miRNA profiles. miRNA sequencing identified 33 differentially enriched miRNAs between MOM_EV and PMOM_EV. These changes correlated with significant decreases in the ability of PMOM_EV to modulate IL-8 secretion in intestinal Caco2 cells where only MOM_EV were able to decrease IL-8 secretion in presence of TNFα. While EVs from MOM_EV and PMOM_EV were both able to induce a tolerogenic M2-like phenotype in THP-1 macrophages, a significant decrease in the transcript levels of IL-10 and RNA sensing genes was observed with PMOM_EV. Together, our data indicates that pasteurization of MOM impacts the integrity and functionality of MOM_EV, decreasing its EVs-mediated immunomodulatory activity. This data provides biomarkers that may be utilized during the optimization of milk processing to preserve its bioactivity.

The Role of Cow's Milk Consumption in Breast Cancer Initiation and Progression

PURPOSE OF REVIEW

This review evaluates cow milk's impact on breast carcinogenesis by linking recent epidemiological evidence and new insights into the molecular signaling of milk and its constituents in breast cancer (BCa) pathogenesis.

RECENT FINDINGS

Recent prospective cohort studies support the association between cow's milk consumption and the risk of estrogen receptor-α-positive (ER⁺) BCa. Milk is a complex biological fluid that increases systemic insulin-like growth factor 1 (IGF-1), insulin and estrogen signaling, and interacting hormonal promoters of BCa. Further potential oncogenic components of commercial milk include exosomal microRNAs (miR-148a-3p, miR-21-5p), bovine meat and milk factors, aflatoxin M1, bisphenol A, pesticides, and micro- and nanoplastics. Individuals with BRCA1 loss-of-function mutations and FTO and IGF1 gain-of-function polymorphisms enhancing IGF-1/mTORC1 signaling may be at increased risk for milk-induced ER⁺ BCa. Recent prospective epidemiological and pathobiochemical studies identify commercial milk consumption as a critical risk factor of ER⁺ BCa. Large meta-analyses gathering individuals of different ethnic origins with milk derived from dairy cows of varying genetic backgrounds and diverse feeding procedures as well as missing data on thermal processing of milk (pasteurization versus ultra-heat treatment) make multi-national meta-analyses unsuitable for BCa risk estimations in susceptible populations. Future studies are required that consider all vulnerable periods of breast carcinogenesis to cow's milk exposure, beginning during the perinatal period and puberty, since these are the most critical periods of mammary gland morphogenesis. Notwithstanding the need for better studies including detailed information on milk processing and vulnerable periods of human breast carcinogenesis, the available evidence suggests that dietary guidelines on milk consumption may have to be reconsidered.

Milk Exosomal microRNAs: Postnatal Promoters of β Cell Proliferation but Potential Inducers of β Cell De-Differentiation in Adult Life

Pancreatic β cell expansion and functional maturation during the birth-to-weaning period is driven by epigenetic programs primarily triggered by growth factors, hormones, and nutrients provided by human milk. As shown recently, exosomes derived from various origins interact with β cells. This review elucidates the potential role of milk-derived exosomes (MEX) and their microRNAs (miRs) on pancreatic β cell programming during the postnatal period of lactation as well as during continuous cow milk exposure of adult humans to bovine MEX. Mechanistic evidence suggests that MEX miRs stimulate mTORC1/c-MYC-dependent postnatal β cell proliferation and glycolysis, but attenuate β cell differentiation, mitochondrial function, and insulin synthesis and secretion. MEX miR content is negatively affected by maternal obesity, gestational diabetes, psychological stress, caesarean delivery, and is completely absent in infant formula. Weaning-related disappearance of MEX miRs may be the critical event switching β cells from proliferation to TGF-β/AMPK-mediated cell differentiation, whereas continued exposure of adult humans to bovine MEX miRs via intake of pasteurized cow milk may reverse β cell differentiation, promoting β cell de-differentiation. Whereas MEX miR signaling supports postnatal β cell proliferation (diabetes prevention), persistent bovine MEX exposure after the lactation period may de-differentiate β cells back to the postnatal phenotype (diabetes induction).

Non-coding RNAs in diabetes mellitus and diabetic cardiovascular disease

More than 10% of the world's population already suffers from varying degrees of diabetes mellitus (DM), but there is still no cure for the disease. Cardiovascular disease (CVD) is one of the most common and dangerous of the many health complications that can be brought on by DM, and has become the leading cause of death in people with diabetes. While research on DM and associated CVD is advancing, the specific mechanisms of their development are still unclear. Given the threat of DM and CVD to humans, the search for new predictive markers and therapeutic ideas is imminent. Non-coding RNAs (ncRNAs) have been a popular subject of research in recent years. Although they do not encode proteins, they play an important role in living organisms, and they can cause disease when their expression is abnormal. Numerous studies have observed aberrant ncRNAs in patients with DM complications, suggesting that they may play an important role in the development of DM and CVD and could potentially act as biomarkers for diagnosis. There is additional evidence that treatment with existing drugs for DM, such as metformin, alters ncRNA expression levels, suggesting that regulation of ncRNA expression may be a key mechanism in future DM treatment. In this review, we assess the role of ncRNAs in the development of DM and CVD, as well as the evidence for ncRNAs as potential therapeutic targets, and make use of bioinformatics to analyze differential ncRNAs with potential functions in DM.

Exosome-Derived MicroRNAs of Human Milk and Their Effects on Infant Health and Development

Multiple biologically active components of human milk support infant growth, health and development. Milk provides a wide spectrum of mammary epithelial cell-derived extracellular vesicles (MEVs) for the infant. Although the whole spectrum of MEVs appears to be of functional importance for the growing infant, the majority of recent studies report on the MEV subfraction of milk exosomes (MEX) and their miRNA cargo, which are in the focus of this review. MEX and the dominant miRNA-148a play a key role in intestinal maturation, barrier function and suppression of nuclear factor-κB (NF-κB) signaling and may thus be helpful for the prevention and treatment of necrotizing enterocolitis. MEX and their miRNAs reach the systemic circulation and may impact epigenetic programming of various organs including the liver, thymus, brain, pancreatic islets, beige, brown and white adipose tissue as well as bones. Translational evidence indicates that MEX and their miRNAs control the expression of global cellular regulators such as DNA methyltransferase 1-which is important for the up-regulation of developmental genes including insulin, insulin-like growth factor-1, α-synuclein and forkhead box P3-and receptor-interacting protein 140, which is important for the regulation of multiple nuclear receptors. MEX-derived miRNA-148a and miRNA-30b may stimulate the expression of uncoupling protein 1, the key inducer of thermogenesis converting white into beige/brown adipose tissue. MEX have to be considered as signalosomes derived from the maternal lactation genome emitted to promote growth, maturation, immunological and metabolic programming of the offspring. Deeper insights into milk's molecular biology allow the conclusion that infants are both "breast-fed" and "breast-programmed". In this regard, MEX miRNA-deficient artificial formula is not an adequate substitute for breastfeeding, the birthright of all mammals.

Pasteurized non-fermented cow's milk but not fermented milk is a promoter of mTORC1-driven aging and increased mortality

Recent epidemiological studies in Sweden, a country with traditionally high milk consumption, revealed that the intake of non-fermented pasteurized milk increased all-cause mortality in a dose-dependent manner. In contrast, the majority of epidemiological and clinical studies report beneficial health effects of fermented milk products, especially of yogurt. It is the intention of this review to delineate potential molecular aging mechanisms related to the intake of non-fermented milk versus yogurt on the basis of mechanistic target of rapamycin complex 1 (mTORC1) signaling. Non-fermented pasteurized milk via its high bioavailability of insulinotropic branched-chain amino acids (BCAAs), abundance of lactose (glucosyl-galactose) and bioactive exosomal microRNAs (miRs) enhances mTORC1 signaling, which shortens lifespan and increases all-cause mortality. In contrast, fermentation-associated lactic acid bacteria metabolize BCAAs and degrade galactose and milk exosomes including their mTORC1-activating microRNAs. The Industrial Revolution, with the introduction of pasteurization and refrigeration of milk, restricted the action of beneficial milk-fermenting bacteria, which degrade milk's BCAAs, galactose and bioactive miRs that synergistically activate mTORC1. This unrecognized behavior change in humans after the Neolithic revolution increased aging-related over-activation of mTORC1 signaling in humans, who persistently consume large quantities of non-fermented pasteurized cow's milk, a potential risk factor for aging and all-cause mortality.

Branched-Chain Amino Acids Associate Negatively With Postprandial Insulin Secretion in Recent-Onset Diabetes

Context

In addition to unfavorable effects on insulin sensitivity, elevated plasma branched-chain amino acids (BCAA) stimulate insulin secretion, which, over the long-term, could impair pancreatic β-cell function.

Objective

To investigate cross-sectional and prospective associations between circulating BCAA and postprandial β-cell function in recently diagnosed type 1 and type 2 diabetes.

Methods

The study included individuals with well-controlled type 1 and type 2 diabetes (known diabetes duration <12 months) and glucose-tolerant participants (controls) of similar age, sex, and body mass index (n = 10/group) who underwent mixed meal tolerance tests. Plasma BCAA levels were quantified by gas chromatography-mass spectrometry, postprandial β-cell function was assessed from serum C-peptide levels, and insulin sensitivity was determined from PREDIM index (PREDIcted M-value).

Results

In type 1 diabetes, postprandial total BCAA, valine, and leucine levels were 25%, 18%, and 19% higher vs control, and total as well as individual postprandial BCAA were related inversely to C-peptide levels. In type 2 diabetes, postprandial isoleucine was 16% higher vs the respective controls, while neither total nor individual BCAA correlated with C-peptide levels. Whole-body insulin sensitivity was lower in both diabetes groups than in corresponding controls.

Conclusion

Insulin deficiency associates with sustained high BCAA concentrations, which could contribute to exhausting the insulin secretory reserve in early type 1 diabetes.

Dairy consumption and hepatocellular carcinoma risk

This review provides epidemiological and translational evidence for milk and dairy intake as critical risk factors in the pathogenesis of hepatocellular carcinoma (HCC). Large epidemiological studies in the United States and Europe identified total dairy, milk and butter intake with the exception of yogurt as independent risk factors of HCC. Enhanced activity of mechanistic target of rapamycin complex 1 (mTORC1) is a hallmark of HCC promoted by hepatitis B virus (HBV) and hepatitis C virus (HCV). mTORC1 is also activated by milk protein-induced synthesis of hepatic insulin-like growth factor 1 (IGF-1) and branched-chain amino acids (BCAAs), abundant constituents of milk proteins. Over the last decades, annual milk protein-derived BCAA intake increased 3 to 5 times in Western countries. In synergy with HBV- and HCV-induced secretion of hepatocyte-derived exosomes enriched in microRNA-21 (miR-21) and miR-155, exosomes of pasteurized milk as well deliver these oncogenic miRs to the human liver. Thus, milk exosomes operate in a comparable fashion to HBV- or HCV- induced exosomes. Milk-derived miRs synergistically enhance IGF-1-AKT-mTORC1 signaling and promote mTORC1-dependent translation, a meaningful mechanism during the postnatal growth phase, but a long-term adverse effect promoting the development of HCC. Both, dietary BCAA abundance combined with oncogenic milk exosome exposure persistently overstimulate hepatic mTORC1. Chronic alcohol consumption as well as type 2 diabetes mellitus (T2DM), two HCC-related conditions, increase BCAA plasma levels. In HCC, mTORC1 is further hyperactivated due to RAB1 mutations as well as impaired hepatic BCAA catabolism, a metabolic hallmark of T2DM. The potential HCC-preventive effect of yogurt may be caused by lactobacilli-mediated degradation of BCAAs, inhibition of branched-chain α-ketoacid dehydrogenase kinase via production of intestinal medium-chain fatty acids as well as degradation of milk exosomes including their oncogenic miRs. A restriction of total animal protein intake realized by a vegetable-based diet is recommended for the prevention of HCC.

Functional maturation of immature β cells: A roadblock for stem cell therapy for type 1 diabetes

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease caused by the specific destruction of pancreatic islet β cells and is characterized as the absolute insufficiency of insulin secretion. Current insulin replacement therapy supplies insulin in a non-physiological way and is associated with devastating complications. Experimental islet transplantation therapy has been proven to restore glucose homeostasis in people with severe T1DM. However, it is restricted by many factors such as severe shortage of donor sources, progressive loss of donor cells, high cost, etc. As pluripotent stem cells have the potential to give rise to all cells including islet β cells in the body, stem cell therapy for diabetes has attracted great attention in the academic community and the general public. Transplantation of islet β-like cells differentiated from human pluripotent stem cells (hPSCs) has the potential to be an excellent alternative to islet transplantation. In stem cell therapy, obtaining β cells with complete insulin secretion in vitro is crucial. However, after much research, it has been found that the β-like cells obtained by in vitro differentiation still have many defects, including lack of adult-type glucose stimulated insulin secretion, and multi-hormonal secretion, suggesting that in vitro culture does not allows for obtaining fully mature β-like cells for transplantation. A large number of studies have found that many transcription factors play important roles in the process of transforming immature to mature human islet β cells. Furthermore, PDX1, NKX6.1, SOX9, NGN3, PAX4, etc., are important in inducing hPSC differentiation in vitro. The absent or deficient expression of any of these key factors may lead to the islet development defect in vivo and the failure of stem cells to differentiate into genuine functional β-like cells in vitro. This article reviews β cell maturation in vivo and in vitro and the vital roles of key molecules in this process, in order to explore the current problems in stem cell therapy for diabetes.

Lifetime Impact of Cow's Milk on Overactivation of mTORC1: From Fetal to Childhood Overgrowth, Acne, Diabetes, Cancers, and Neurodegeneration

The consumption of cow's milk is a part of the basic nutritional habits of Western industrialized countries. Recent epidemiological studies associate the intake of cow's milk with an increased risk of diseases, which are associated with overactivated mechanistic target of rapamycin complex 1 (mTORC1) signaling. This review presents current epidemiological and translational evidence linking milk consumption to the regulation of mTORC1, the master-switch for eukaryotic cell growth. Epidemiological studies confirm a correlation between cow's milk consumption and birthweight, body mass index, onset of menarche, linear growth during childhood, acne vulgaris, type 2 diabetes mellitus, prostate cancer, breast cancer, hepatocellular carcinoma, diffuse large B-cell lymphoma, neurodegenerative diseases, and all-cause mortality. Thus, long-term persistent consumption of cow's milk increases the risk of mTORC1-driven diseases of civilization. Milk is a highly conserved, lactation genome-controlled signaling system that functions as a maternal-neonatal relay for optimized species-specific activation of mTORC1, the nexus for regulation of eukaryotic cell growth, and control of autophagy. A deeper understanding of milk´s impact on mTORC1 signaling is of critical importance for the prevention of common diseases of civilization.

Synergistic Effects of Milk-Derived Exosomes and Galactose on α-Synuclein Pathology in Parkinson's Disease and Type 2 Diabetes Mellitus

Epidemiological studies associate milk consumption with an increased risk of Parkinson's disease (PD) and type 2 diabetes mellitus (T2D). PD is an α-synucleinopathy associated with mitochondrial dysfunction, oxidative stress, deficient lysosomal clearance of α-synuclein (α-syn) and aggregation of misfolded α-syn. In T2D, α-syn promotes co-aggregation with islet amyloid polypeptide in pancreatic β-cells. Prion-like vagal nerve-mediated propagation of exosomal α-syn from the gut to the brain and pancreatic islets apparently link both pathologies. Exosomes are critical transmitters of α-syn from cell to cell especially under conditions of compromised autophagy. This review provides translational evidence that milk exosomes (MEX) disturb α-syn homeostasis. MEX are taken up by intestinal epithelial cells and accumulate in the brain after oral administration to mice. The potential uptake of MEX miRNA-148a and miRNA-21 by enteroendocrine cells in the gut, dopaminergic neurons in substantia nigra and pancreatic β-cells may enhance miRNA-148a/DNMT1-dependent overexpression of α-syn and impair miRNA-148a/PPARGC1A- and miRNA-21/LAMP2A-dependent autophagy driving both diseases. MiRNA-148a- and galactose-induced mitochondrial oxidative stress activate c-Abl-mediated aggregation of α-syn which is exported by exosome release. Via the vagal nerve and/or systemic exosomes, toxic α-syn may spread to dopaminergic neurons and pancreatic β-cells linking the pathogenesis of PD and T2D.

miR-497 regulates fatty acid synthesis via LATS2 in bovine mammary epithelial cells

Both mRNA and miRNA play an important role in the regulation of mammary fatty acid metabolism and milk fat synthesis.

Milk exosomal miRNAs: potential drivers of AMPK-to-mTORC1 switching in β-cell de-differentiation of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) steadily increases in prevalence since the 1950's, the period of widespread distribution of refrigerated pasteurized cow's milk. Whereas breastfeeding protects against the development of T2DM in later life, accumulating epidemiological evidence underlines the role of cow's milk consumption in T2DM. Recent studies in rodent models demonstrate that during the breastfeeding period pancreatic β-cells are metabolically immature and preferentially proliferate by activation of mechanistic target of rapamycin complex 1 (mTORC1) and suppression of AMP-activated protein kinase (AMPK). Weaning determines a metabolic switch of β-cells from a proliferating, immature phenotype with low insulin secretion to a differentiated mature phenotype with glucose-stimulated insulin secretion, less proliferation, reduced mTORC1- but increased AMPK activity. Translational evidence presented in this perspective implies for the first time that termination of milk miRNA transfer is the driver of this metabolic switch. miRNA-148a is a key inhibitor of AMPK and phosphatase and tensin homolog, crucial suppressors of mTORC1. β-Cells of diabetic patients return to the postnatal phenotype with high mTORC1 and low AMPK activity, explained by continuous transfer of bovine milk miRNAs to the human milk consumer. Bovine milk miRNA-148a apparently promotes β-cell de-differentiation to the immature mTORC1-high/AMPK-low phenotype with functional impairments in insulin secretion, increased mTORC1-driven endoplasmic reticulum stress, reduced autophagy and early β-cell apoptosis. In contrast to pasteurized cow's milk, milk's miRNAs are inactivated by bacterial fermentation, boiling and ultra-heat treatment and are missing in current infant formula. Persistent milk miRNA signaling adds a new perspective to the pathogenesis of T2DM and explains the protective role of breastfeeding but the diabetogenic effect of continued milk miRNA signaling by persistent consumption of pasteurized cow's milk.

Dairy Products: Is There an Impact on Promotion of Prostate Cancer? A Review of the Literature

This review of the literature aims to study potential associations between high consumption of milk and/or dairy products and prostate cancer (PC). Literature is scarce, yet there is a direct relationship between mTORC1 activation and PC; several ingredients in milk/dairy products, when in high concentrations, increase signaling of the mTORC1 pathway. However, there are no studies showing an unequivocal relationship between milk products PC initiation and/or progression. Three different reviews were conducted with articles published in the last 5 years: (M1) PC and intake of dairy products, taking into account the possible mTORC1signaling mechanism; (M2) Intake of milk products and incidence/promotion of PC; (M3) mTORC1 activation signaling pathway, levels of IGF-1 and PC; (M4) mTORC pathway and dairy products. Of the 32 reviews identified, only 21 met the inclusion criteria and were analyzed. There is little scientific evidence that directly link the three factors: incidence/promotion of PC, intake of dairy products and PC, and PC and increased mTORC1 signaling. Persistent hyper-activation of mTORC1 is associated with PC promotion. The activity of exosomal mRNA in cellular communication may lead to different impacts of different types of milk and whether or not mammalian milks will have their own characteristics within each species. Based on this review of the literature, it is possible to establish a relationship between the consumption of milk products and the progression of PC; we also found a possible association with PC initiation, hence it is likely that the intake of dairy products should be reduced or minimized in mens' diet.

A therapeutic approach towards microRNA29 family in vascular diabetic complications: A boon or curse?

Diabetes Mellitus (DM) is one of the major metabolic disorders and its severity leads to death. Enhancement in hyperglycaemic conditions of DM gives rise to endothelial impairment in small and large blood vessels contributing towards microvascular and macrovascular complications respectively. The pathogenesis of diabetic complications is associated with interruption of various signal transduction pathways due to epigenetic modifications such as aberrant histone modifications, DNA methylation and expression of miRNAs along with the long non-coding RNAs (lncRNAs). Amongst these epigenetic alterations, modulated expressions of miRNAs confer to apoptosis and endothelial dysfunction of organs that gives rise to vascular complications. In this review, we principally focussed on physiological role of miR29 family in DM and have discussed crosstalk between miR29 family and numerous genes involved in signal transduction pathways of Diabetic vascular complications. Incidences of diabetic retinopathy exploiting the role of miR29 in regulation of EMT process, differential expression patterns of miR29 and promising therapeutic role of miR29 have been discussed. We have summarised the therapeutic role of miR29 in podocyte impairment and how miR29 regulates the expressions of profibrotic, inflammatory and ECM encoding genes in renal fibrosis under diabetic conditions. We have also highlighted impact of miR29 expression patterns in cardiac angiopathy, cardiomyocyte's apoptosis and cardiac fibrosis. Additionally, we have also presented the contradictory actions of miR29 family in amelioration as well as in enhancement of diabetic complications.

Milk MicroRNAs in Health and Disease

MicroRNAs are small noncoding RNAs responsible for regulating 40% to 60% of gene expression at the posttranscriptional level. The discovery of circulating microRNAs in several biological fluids opened the path for their study as biomarkers and long-range cell-to-cell communication mediators. Their transfer between individuals in the case of blood transfusion, for example, and their high enrichment in milk have sparked the interest for microRNA transfer through diet, especially from mothers to infants during breastfeeding. The extension of such paradigm led to the study of milk microRNAs in the case of cow or goat milk consumption in adults. Here we provide a comprehensive critical review of the key findings surrounding milk microRNAs in human, cow, and goat milk among other species. We discuss the data on their biological properties, their use as disease biomarkers, their transfer between individuals or species, and their putative or verified functions in health and disease of infants and adult consumers. This work is based on all the literature available and integrates all the results, theories, debates, and validation studies available so far on milk microRNAs and related areas of investigations. We critically discuss the limitations and outline future aspects and avenues to explore in this rapidly growing field of research that could impact public health through infant milk formulations or new therapies. We hope that this comprehensive review of the literature will provide insight for all teams investigating milk RNAs' biological activities and help ensure the quality of future reports.

Exosomes of pasteurized milk: potential pathogens of Western diseases

Milk consumption is a hallmark of western diet. According to common believes, milk consumption has beneficial effects for human health. Pasteurization of cow's milk protects thermolabile vitamins and other organic compounds including bioactive and bioavailable exosomes and extracellular vesicles in the range of 40-120 nm, which are pivotal mediators of cell communication via systemic transfer of specific micro-ribonucleic acids, mRNAs and regulatory proteins such as transforming growth factor-β. There is compelling evidence that human and bovine milk exosomes play a crucial role for adequate metabolic and immunological programming of the newborn infant at the beginning of extrauterine life. Milk exosomes assist in executing an anabolic, growth-promoting and immunological program confined to the postnatal period in all mammals. However, epidemiological and translational evidence presented in this review indicates that continuous exposure of humans to exosomes of pasteurized milk may confer a substantial risk for the development of chronic diseases of civilization including obesity, type 2 diabetes mellitus, osteoporosis, common cancers (prostate, breast, liver, B-cells) as well as Parkinson's disease. Exosomes of pasteurized milk may represent new pathogens that should not reach the human food chain.

Diseases of Civilization - Cancer, Diabetes, Obesity and Acne - the Implication of Milk, IGF-1 and mTORC1

Nutrition and food are one of the most complex aspects of human lives, being influenced by biochemical, psychological, social and cultural factors. The Western diet is the prototype of modern dietary pattern and is mainly characterized by the intake of large amounts of red meat, dairy products, refined grains and sugar. Large amounts of scientific evidence positively correlate Western diet to acne, obesity, diabetes, heart disease and cancer, the so-called "diseases of civilization". The pathophysiological common ground of all these pathologies is the IGF-1 and mTORC pathways, which will be disscussed further in this paper.

Insights into the key roles of epigenetics in matrix macromolecules-associated wound healing

Extracellular matrix (ECM) is a dynamic network of macromolecules, playing a regulatory role in cell functions, tissue regeneration and remodeling. Wound healing is a tissue repair process necessary for the maintenance of the functionality of tissues and organs. This highly orchestrated process is divided into four temporally overlapping phases, including hemostasis, inflammation, proliferation and tissue remodeling. The dynamic interplay between ECM and resident cells exerts its critical role in many aspects of wound healing, including cell proliferation, migration, differentiation, survival, matrix degradation and biosynthesis. Several epigenetic regulatory factors, such as the endogenous non-coding microRNAs (miRNAs), are the drivers of the wound healing response. microRNAs have pivotal roles in regulating ECM composition during wound healing and dermal regeneration. Their expression is associated with the distinct phases of wound healing and they serve as target biomarkers and targets for systematic regulation of wound repair. In this article we critically present the importance of epigenetics with particular emphasis on miRNAs regulating ECM components (i.e. glycoproteins, proteoglycans and matrix proteases) that are key players in wound healing. The clinical relevance of miRNA targeting as well as the delivery strategies designed for clinical applications are also presented and discussed.

MicroRNA-29: A Crucial Player in Fibrotic Disease

Fibrosis is a common pathological state characterized by the excessive accumulation of extracellular matrix components, but the pathogenesis of the disease is still not clear. Previous studies have shown that microRNA-29 (miR-29) can play pivotal roles in the regulation of a variety of organ fibrosis, including cardiac fibrosis, hepatic fibrosis, lung fibrosis, systemic sclerosis, and keloid. In this review, we outline the structure, expression, and regulation of miR-29 as well as its role in fibrotic diseases.

Milk's Role as an Epigenetic Regulator in Health and Disease

It is the intention of this review to characterize milk's role as an epigenetic regulator in health and disease. Based on translational research, we identify milk as a major epigenetic modulator of gene expression of the milk recipient. Milk is presented as an epigenetic "doping system" of mammalian development. Milk exosome-derived micro-ribonucleic acids (miRNAs) that target DNA methyltransferases are implicated to play the key role in the upregulation of developmental genes such as FTO, INS, and IGF1. In contrast to miRNA-deficient infant formula, breastfeeding via physiological miRNA transfer provides the appropriate signals for adequate epigenetic programming of the newborn infant. Whereas breastfeeding is restricted to the lactation period, continued consumption of cow's milk results in persistent epigenetic upregulation of genes critically involved in the development of diseases of civilization such as diabesity, neurodegeneration, and cancer. We hypothesize that the same miRNAs that epigenetically increase lactation, upregulate gene expression of the milk recipient via milk-derived miRNAs. It is of critical concern that persistent consumption of pasteurized cow's milk contaminates the human food chain with bovine miRNAs, that are identical to their human analogs. Commercial interest to enhance dairy lactation performance may further increase the epigenetic miRNA burden for the milk consumer.

Depurinized milk downregulates rat thymus MyD88/Akt/p38 function, NF-κB-mediated inflammation, caspase-1 activity but not the endonuclease pathway: in vitro/in vivo study

The aim of this study was the evaluation of 15 days dietary regimen of depurinized (DP) milk (obtained using our patented technological procedures) or 1.5% fat UHT milk instead of standard chow diet, on rat thymus and bone marrow MyD88/Akt/p38, NF-κB, caspase-1 and endonuclease pathways, in relation to peripheral blood cell composition. To determine whether the reduced mass of the thymus is a consequence of the direct effect of DP/UHT milk on apoptosis of thymocytes, in vitro Annexin-V-FITC/PI assay was performed. Significant decreases in the thymus wet weight, thymocyte MyD88, Akt-1/phospho-Akt-1 kinase, p38/phospho-p38, NF-κB, caspase-1 activity and CD4+/CD8+ antigen expression were obtained, especially in the DP milk group. The activity of thymocyte alkaline and acid DNase increased in the DP but not in the UHT milk group. The level of IL-6 significantly decreased in DP milk treated group, while the level of total TGF-β and IL-6 increased in UHT milk group. Significant differences in hematological parameters were obtained in commercial milk fed group. Observed results about prevention of experimental diabetes in DP pretreated groups may suggest that purine compounds, uric acid and other volatile toxic compounds of commercial milk may suppress oral tolerance, probably via IL-6 and TGF-β cytokine effects.

Dysregulation between TRIM63/FBXO32 expression and soleus muscle wasting in diabetic rats: potential role of miR-1-3p, -29a/b-3p, and -133a/b-3p

Diabetes mellitus (DM) induces a variable degree of muscle sarcopenia, which may be related to protein degradation and to the expression of both E3 ubiquitin ligases and some specific microRNAs (miRNAs). The present study investigated the effect of diabetes and acute muscle contraction upon the TRIM63 and FBXO32 expression as well as the potential involvement of some miRNAs. Diabetes was induced by streptozotocin and studied after 30 days. Soleus muscles were harvested, stimulated to contract in vitro for twitch tension analysis (0.5 Hz), 30 min later for tetanic analysis (100 Hz), and 30 min later were frozen. TRIM63 and FBXO32 proteins were quantified by western blotting; Trim63 mRNA, Fbxo32 mRNA, miR-1-3p, miR-29a-3p, miR-29b-3p, miR-133a-3p, and miR-133b-3p were quantified by qPCR. Diabetes induced sarcopenia by decreasing (P < 0.05) muscle weight/tibia length index, maximum tetanic contraction and relaxation rates, and absolute twitch and tetanic forces (P < 0.05). Diabetes decreased (P < 0.05) the Trim63 and Fbxo32 mRNAs (30%) and respective proteins (60%), and increased (P < 0.01) the miR-29b-3p (2.5-fold). In muscle from diabetic rats, acute contractile stimulus increased TRIM63 protein, miR-1-3p, miR-29a-3p, and miR-133a/b-3p, but decreased miR-29b-3p (P < 0.05). Independent of the metabolic condition, after muscle contraction, both TRIM63 and FBXO32 proteins correlated significantly with miR-1-3p, miR-29a/b-3p, and miR-133a/b-3p. All diabetes-induced regulations were reversed by insulin treatment. Concluding, the results depict that muscle wasting in long-term insulinopenic condition may not be accompanied by increased proteolysis, pointing out the protein synthesis as an important modulator of muscle sarcopenia in DM.

Potential relevance of microRNAs in inter-species epigenetic communication, and implications for disease pathogenesis

MicroRNAs are short non-protein coding RNA molecules involved in the epigenetic regulation of gene expression. Recently, extracellular microRNAs have been described in body fluids that might enable epigenetic communication between distant tissues. Being highly conserved molecules, exogenous xeno-microRNAs from different species could affect gene expression in the host even in a cross-kingdom fashion. Several data underline the relevance of microRNA-mediated communication between virus and host, and there are some experimental data showing that plant- or animal-derived dietary microRNAs might have gene expression modulating activity in humans. Milk-derived microRNAs might be involved in the "epigenetic priming" of the baby. Exogenous microRNAs might be hypothesized to be implicated in disease pathogenesis, e.g. in tumors. Major questions remain to be addressed including the amount of xeno-microRNAs needed for biological action or routes for microRNA delivery. In this brief review, experimental data and hypotheses on the potential pathogenic inter-species relevance of microRNA are presented.

Dopamine pathway gene variants may modulate cognitive performance in the DHS - Mind Study

BACKGROUND

There is an established association between type 2 diabetes and accelerated cognitive decline. The exact mechanism linking type 2 diabetes and reduced cognitive function is less clear. The monoamine system, which is extensively involved in cognition, can be altered by type 2 diabetes status. Thus, this study hypothesized that sequence variants in genes linked to dopamine metabolism and associated pathways are associated with cognitive function as assessed by the Digit Symbol Substitution Task, the Modified Mini-Mental State Examination, the Stroop Task, the Rey Auditory-Verbal Learning Task, and the Controlled Oral Word Association Task for Phonemic and Semantic Fluency in the Diabetes Heart Study, a type 2 diabetes-enriched familial cohort (n = 893).

METHODS

To determine the effects of candidate variants on cognitive performance, genetic association analyses were performed on the well-documented variable number tandem repeat located in the 3' untranslated region of the dopamine transporter, as well as on single-nucleotide polymorphisms covering genes in the dopaminergic pathway, the insulin signaling pathway, and the convergence of both. Next, polymorphisms in loci of interest with strong evidence for involvement in dopamine processing were extracted from genetic datasets available in a subset of the cohort (n = 572) derived from Affymetrix(®) Genome-Wide Human SNP Array 5.0 and 1000 Genomes imputation from this array.

RESULTS

The candidate gene analysis revealed one variant from the DOPA decarboxylase gene, rs10499695, to be associated with poorer performance on a subset of Rey Auditory-Verbal Learning Task measuring retroactive interference (P = 0.001, β = -0.45). Secondary analysis of genome-wide and imputed data uncovered another DOPA decarboxylase variant, rs62445903, also associated with retroactive interference (P = 7.21 × 10(-7), β = 0.3). These data suggest a role for dopaminergic genes, specifically a gene involved in regulation of dopamine synthesis, in cognitive performance in type 2 diabetes.

Milk: an epigenetic amplifier of FTO-mediated transcription? Implications for Western diseases

Single-nucleotide polymorphisms within intron 1 of the FTO (fat mass and obesity-associated) gene are associated with enhanced FTO expression, increased body weight, obesity and type 2 diabetes mellitus (T2DM). The N⁶-methyladenosine (m⁶A) demethylase FTO plays a pivotal regulatory role for postnatal growth and energy expenditure. The purpose of this review is to provide translational evidence that links milk signaling with FTO-activated transcription of the milk recipient. FTO-dependent demethylation of m⁶A regulates mRNA splicing required for adipogenesis, increases the stability of mRNAs, and affects microRNA (miRNA) expression and miRNA biosynthesis. FTO senses branched-chain amino acids (BCAAs) and activates the nutrient sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), which plays a key role in translation. Milk provides abundant BCAAs and glutamine, critical components increasing FTO expression. CpG hypomethylation in the first intron of FTO has recently been associated with T2DM. CpG methylation is generally associated with gene silencing. In contrast, CpG demethylation generally increases transcription. DNA de novo methylation of CpG sites is facilitated by DNA methyltransferases (DNMT) 3A and 3B, whereas DNA maintenance methylation is controlled by DNMT1. MiRNA-29s target all DNMTs and thus reduce DNA CpG methylation. Cow´s milk provides substantial amounts of exosomal miRNA-29s that reach the systemic circulation and target mRNAs of the milk recipient. Via DNMT suppression, milk exosomal miRNA-29s may reduce the magnitude of FTO methylation, thereby epigenetically increasing FTO expression in the milk consumer. High lactation performance with increased milk yield has recently been associated with excessive miRNA-29 expression of dairy cow mammary epithelial cells (DCMECs). Notably, the galactopoietic hormone prolactin upregulates the transcription factor STAT3, which induces miRNA-29 expression. In a retrovirus-like manner milk exosomes may transfer DCMEC-derived miRNA-29s and bovine FTO mRNA to the milk consumer amplifying FTO expression. There is compelling evidence that obesity, T2DM, prostate and breast cancer, and neurodegenerative diseases are all associated with increased FTO expression. Maximization of lactation performance by veterinary medicine with enhanced miRNA-29s and FTO expression associated with increased exosomal miRNA-29 and FTO mRNA transfer to the milk consumer may represent key epigenetic mechanisms promoting FTO/mTORC1-mediated diseases of civilization.

The Biochemical Cascades of the Human Pancreatic β-Cells: The Role of MicroRNAs

Diabetes mellitus is a disease that poses a burden to the health care system due to its prevalence and chronic nature. Understanding β cell pathophysiology may lead to future therapeutic options for diabetes mellitus type 1 and 2. MicroRNAs (MiR) fine-tune β cell biochemical cascades through specific protein targets. This review argues that miRs may play a critical role in human islet β cell biology and are potential candidates for a new pharmacological strategy. We have reviewed and presented how miRs fine tune four biochemical cascades in islet β cells: glucose stimulated insulin secretion, β cell replication, apoptosis, and development. Only studies that examine human pancreatic islets either in vitro or in vivo are included. The unveiling role of miR pathways in regulating human islet β cell biology could open the door for diagnostic and therapeutic methods for diabetes mellitus prevention and therapy.

Milk--A Nutrient System of Mammalian Evolution Promoting mTORC1-Dependent Translation

Based on own translational research of the biochemical and hormonal effects of cow's milk consumption in humans, this review presents milk as a signaling system of mammalian evolution that activates the nutrient-sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), the pivotal regulator of translation. Milk, a mammary gland-derived secretory product, is required for species-specific gene-nutrient interactions that promote appropriate growth and development of the newborn mammal. This signaling system is highly conserved and tightly controlled by the lactation genome. Milk is sufficient to activate mTORC1, the crucial regulator of protein, lipid, and nucleotide synthesis orchestrating anabolism, cell growth and proliferation. To fulfill its mTORC1-activating function, milk delivers four key metabolic messengers: (1) essential branched-chain amino acids (BCAAs); (2) glutamine; (3) palmitic acid; and (4) bioactive exosomal microRNAs, which in a synergistical fashion promote mTORC1-dependent translation. In all mammals except Neolithic humans, postnatal activation of mTORC1 by milk intake is restricted to the postnatal lactation period. It is of critical concern that persistent hyperactivation of mTORC1 is associated with aging and the development of age-related disorders such as obesity, type 2 diabetes mellitus, cancer, and neurodegenerative diseases. Persistent mTORC1 activation promotes endoplasmic reticulum (ER) stress and drives an aimless quasi-program, which promotes aging and age-related diseases.

Linking diet to acne metabolomics, inflammation, and comedogenesis: an update

Acne vulgaris, an epidemic inflammatory skin disease of adolescence, is closely related to Western diet. Three major food classes that promote acne are: 1) hyperglycemic carbohydrates, 2) milk and dairy products, 3) saturated fats including trans-fats and deficient ω-3 polyunsaturated fatty acids (PUFAs). Diet-induced insulin/insulin-like growth factor (IGF-1)-signaling is superimposed on elevated IGF-1 levels during puberty, thereby unmasking the impact of aberrant nutrigenomics on sebaceous gland homeostasis. Western diet provides abundant branched-chain amino acids (BCAAs), glutamine, and palmitic acid. Insulin and IGF-1 suppress the activity of the metabolic transcription factor forkhead box O1 (FoxO1). Insulin, IGF-1, BCAAs, glutamine, and palmitate activate the nutrient-sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), the key regulator of anabolism and lipogenesis. FoxO1 is a negative coregulator of androgen receptor, peroxisome proliferator-activated receptor-γ (PPARγ), liver X receptor-α, and sterol response element binding protein-1c (SREBP-1c), crucial transcription factors of sebaceous lipogenesis. mTORC1 stimulates the expression of PPARγ and SREBP-1c, promoting sebum production. SREBP-1c upregulates stearoyl-CoA- and Δ6-desaturase, enhancing the proportion of monounsaturated fatty acids in sebum triglycerides. Diet-mediated aberrations in sebum quantity (hyperseborrhea) and composition (dysseborrhea) promote Propionibacterium acnes overgrowth and biofilm formation with overexpression of the virulence factor triglyceride lipase increasing follicular levels of free palmitate and oleate. Free palmitate functions as a "danger signal," stimulating toll-like receptor-2-mediated inflammasome activation with interleukin-1β release, Th17 differentiation, and interleukin-17-mediated keratinocyte proliferation. Oleate stimulates P. acnes adhesion, keratinocyte proliferation, and comedogenesis via interleukin-1α release. Thus, diet-induced metabolomic alterations promote the visible sebofollicular inflammasomopathy acne vulgaris. Nutrition therapy of acne has to increase FoxO1 and to attenuate mTORC1/SREBP-1c signaling. Patients should balance total calorie uptake and restrict refined carbohydrates, milk, dairy protein supplements, saturated fats, and trans-fats. A paleolithic-like diet enriched in vegetables and fish is recommended. Plant-derived mTORC1 inhibitors and ω-3-PUFAs are promising dietary supplements supporting nutrition therapy of acne vulgaris.

Insulin resistance and skin diseases

In medical practice, almost every clinician may encounter patients with skin disease. However, it is not always easy for physicians of all specialties to face the daily task of determining the nature and clinical implication of dermatologic manifestations. Are they confined to the skin, representing a pure dermatologic event? Or are they also markers of internal conditions relating to the patient's overall health? In this review, we will discuss the principal cutaneous conditions which have been linked to metabolic alterations. Particularly, since insulin has an important role in homeostasis and physiology of the skin, we will focus on the relationships between insulin resistance (IR) and skin diseases, analyzing strongly IR-associated conditions such as acanthosis nigricans, acne, and psoriasis, without neglecting emerging and potential scenarios as the ones represented by hidradenitis suppurativa, androgenetic alopecia, and hirsutism.

Hypothetic Interindividual and Interspecies Relevance of microRNAs Released in Body Fluids

MicroRNAs may not only be relevant within the organism, but microRNAs released in body fluids might affect other individuals and hypothetically also other species. Such interindividual and cross-species activity of microRNAs appears to be very interesting, but these actions are largely hypothetic at present warranting extensive experimental validation. Food-derived microRNAs might extend the relevance of food for epigenetic regulation; however, the efficient gastrointestinal transfer of microRNAs needs to be demonstrated. We have raised the hypothesis that the nonprotein coding "dark matter" of the genome containing microRNA genes might be relevant in the regulation of interindividual and interspecies epigenetic communication.