MiR-1-3p and MiR-124-3p Synergistically Damage the Intestinal Barrier in the Ageing Colon.

BACKGROUND AND AIMS: Disruption of the intestinal barrier of the digestive tract is a common pathophysiological change in the elderly, which may partly contribute to gut dysfunction and inflammatory bowel disease [IBD]. This study aimed to discover new interactive epigenetic regulation patterns involved in intestinal barrier dysfunction and colitis in elderly populations. METHODS: Intestinal barrier function and structure were evaluated in naturally ageing mice and elderly people. High-throughput analysis was performed on colonic tissues from humans and mice. The synergistic roles of miR-1-3p and miR-124-3p were identified using microRNA mimic/agomirs. Related genes were examined in biopsies of old IBD patients. RESULTS: A defective mucus barrier was observed before mucosal microstructural damage during ageing. Elevated miR-1-3p expression in the colons of older individuals impaired the mucus barrier by directly targeting T-synthase, similarly to the mechanism of miR-124-3p, which we reported previously. Importantly, the synergistic effect of a half dose of each microRNA supplement on T-synthase and CDK4/6 was stronger than that of a full dose of miR-1-3p or miR-124-3p alone, and mice co-treated with two microRNAs showed greater susceptibility to chemical-induced colitis than mice treated with either microRNA alone. These two microRNAs were up-expressed in old IBD patients. CONCLUSIONS: The slight increases in miR-1-3p and miR-124-3p expression with ageing may be important contributors to the breakdown of intestinal homeostasis by targeting divergent genes in different cells. These data reveal the potential ability of multiple microRNAs to exert synergistic effects to damage the intestinal barrier and promote inflammatory bowel disease development in elderly populations.

Elevated miR-124-3p in the aging colon disrupts mucus barrier and increases susceptibility to colitis by targeting T-synthase.

The risk of colitis and colorectal cancer increases markedly throughout adult life, endangering the health and lives of elderly individuals. Previous studies have proposed that bacterial translocation and infection are the main risk factors for these diseases. Therefore, in the present study, we aimed to identify the underlying mechanism by focusing on the mucus barrier function and mucin-type O-glycosylation. We evaluated alterations in the colon mucus layer in 2-, 16-, and 24-month-old mice and aged humans. Aged colons showed defective intestinal mucosal barrier and changed mucus properties. The miR-124-3p expression level was significantly increased in the aged distal colonic mucosa, which was accompanied by an increase in pathogens and bacterial translocation. Meanwhile, T-synthase, the rate-limiting enzyme in O-glycosylation, displayed an age-related decline in protein expression. Further experiments indicated that miR-124-3p modulated O-glycosylation by directly targeting T-synthase. Moreover, young mice overexpressing miR-124-3p exhibited abnormal glycosylation, early-onset, and more severe colitis. These data suggest that miR-124-3p predisposes to senile colitis by reducing T-synthase, and the miR-124-3p/T-synthase/O-glycans axis plays an essential role in maintaining the physiochemical properties of colonic mucus and intestinal homeostasis.

Conditioned medium from human amniotic epithelial cells may induce the differentiation of human umbilical cord blood mesenchymal stem cells into dopaminergic neuron-like cells.

Dopaminergic (DA) neuron therapy has been established as a new clinical tool for treating Parkinson's disease (PD). Prior to cell transplantation, there are two primary issues that must be resolved: one is the appropriate seed cell origin, and the other is the efficient inducing technique. In the present study, human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) were used as the available seed cells, and conditioned medium from human amniotic epithelial cells (ACM) was used as the inducing reagent. Results showed that the proportion of DA neuron-like cells from hUCB-MSCs was significantly increased after cultured in ACM, suggested by the upregulation of DAT, TH, Nurr1, and Pitx3. To identify the process by which ACM induces DA neuron differentiation, we pretreated hUCB-MSCs with k252a, the Trk receptor inhibitor of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), and found that the proportion of DA neuron-like cells was significantly decreased compared with ACM-treated hUCB-MSCs, suggesting that NGF and BDNF in ACM were involved in the differentiation process. However, we could not rule out the involvement of other unidentified factors in the ACM, because ACM + k252a treatment does not fully block DA neuron-like cell differentiation compared with control. The transplantation of ACM-induced hUCB-MSCs could ameliorate behavioral deficits in PD rats, which may be associated with the survival of engrafted DA neuron-like cells. In conclusion, we propose that hUCB-MSCs are a good source of DA neuron-like cells and that ACM is a potential inducer to obtain DA neuron-like cells from hUCB-MSCs in vitro for an ethical and legal cell therapy for PD.

Pleiotrophin is involved in the amniotic epithelial cell-induced differentiation of human umbilical cord blood-derived mesenchymal stem cells into dopaminergic neuron-like cells.

We have reported that human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) are capable of differentiating into dopaminergic (DA) neuron-like cells upon being induced by amniotic epithelial cells (AECs). However, what factor(s) is involved in the differentiation process has not been explored out thoroughly. Because pleiotrophin (PTN) is known to exert important trophic effects on DA neurons, in the present study, we investigated whether PTN is released by AECs and whether it is involved in the differentiation of hUCB-MSCs into DA neuron-like cells. The expression and secretion of PTN by AECs were detected by immunofluorescence, RT-PCR and ELISA. The hUCB-MSCs were isolated and treated with AEC-conditioned medium (ACM) or recombinant human PTN. Compared to the controls, a higher proportion of treated cells differentiated into DA neuron-like cells, indicated by the increased expression of TH and DAT and the increased dopamine content. These results indicate that PTN released by AECs acts as a synergetic factor with other neurotrophic factors and is involved in the differentiation of hUCB-MSCs into DA neuron-like cells. We suggest that ACM, which contains PTN and other neurotrophic factors, could potentially be used as an agent to promote the differentiation of DA neuron-like cells from hUCB-MSCs for cell therapy of Parkinson's disease without creating legal or ethical issues.