Emerging roles of the long non-coding RNAs MALAT1 and TUG1 during differentiation of adipose tissue-derived mesenchymal stem cells towards insulin-producing cells

Abstract

Background: Generation of insulin-producing cells (IPCs) from stem cells provides great hope for patients with diabetes mellitus (DM). Long non-coding RNAs (lncRNAs) ignited much interest regarding their role in determining the fate of stem cells. The lncRNAs MALAT1 and TUG1 have been reported to be interrelated with β-cell dysfunction and/or DM. However, their role during generation of IPCs from stem cells has not been adequately studied. Thus, the current study aimed to investigate the role of MALAT1 and TUG1 during differentiation of adipose tissue-derived mesenchymal stem cells (Ad-MSCs) towards IPCs. Methods: Ad-MSCs were isolated from rat epididymal fat pads, characterized and induced to differentiate towards IPCs. Assessment of differentiation was done by measuring expression levels of various β-cell-related markers using RT-qPCR, as well as morphological changes, and dithizone staining. Expression levels of MALAT1 and TUG1 were also measured by RT-qPCR. Several in-silico analyses were done using RNA–protein Association and Interaction Networks (RAIN) database. Results: MALAT1 and TUG1 expression levels were significantly increased during differentiation of Ad-MSCs into IPCs as compared to control uninduced cells. Furthermore, generated networks from RAIN database revealed an interplay between MALAT1 and TUG1, and between each of them with several common targets like GAS5, HOTAIR and TP53COR1. Conclusions: The current study portrays MALAT1 and TUG1 as novel interrelated molecular mediators and important regulatory nodes enhancing differentiation of Ad-MSCs towards IPCs. Their upregulation during differentiation can be interrelated with competitive endogenous RNA (ceRNA) networks, mediating various epigenetic modifications, orchestrating signaling pathways and overcoming cellular stress during reprogramming/differentiation.

1. Introduction

Diabetes mellitus (DM) is a serious metabolic disorder marked by varying degrees of loss and/or dysfunction of insulin-secreting β-cells. Unfortunately, the global prevalence of DM is alarmingly rising, currently affecting approximately 589 million individuals worldwide, with Egypt ranking among the top ten most affected countries [1]. Over the past few decades, stem cell-based therapies have emerged as a promising avenue for the treatment of numerous diseases, particularly DM [2, 3]. Among various stem cell types, mesenchymal stem cells (MSCs) specifically have attracted significant attention for their broad reparative capabilities, with more than 1,500 clinical trials investigating their therapeutic applications across diverse diseases [4]. MSCs are highly valued for their ability to mediate reparative effects in diverse forms of tissue injury [5–9], coupled with several key advantages: minimal ethical concerns compared to embryonic stem cells (ESCs), relatively easy isolation procedures, robust ex-vivo expansion, together with their immunomodulatory properties and multipotent differentiation potential [10]. However, the mechanisms underlying their therapeutic and regenerative properties remain much more complex than anticipated and far from complete elucidation [5].

A particularly exciting area of research is the generation of insulin-producing cells (IPCs) from stem cells. Over the past couple of decades, various stem cell sources—including ESCs [11, 12] and MSCs [13, 14]—have demonstrated the ability to differentiate into IPCs. Despite these advances, current differentiation induction protocols remain suboptimal due to several factors such as the complexity of the signaling pathways governing pancreatic lineage specification and the variability between different types of the used stem cells [15, 16]. This highlights the need for further investigations to enhance maturation and functionality of IPCs generated from various types of stem cells. Overcoming these barriers is essential for improving cell therapy outcomes in DM and could also reveal novel therapeutic targets to stimulate β-cell neogenesis/regeneration and combat DM [17, 18].