Differentiated PDGFRα-Positive Cells: A Novel In-Vitro Model for Functional Studies of Neuronal Nitric Oxide Synthase

Cryopreservation and validation of differentiated PDGFRα-positive cells for long term usage in experimentation

OBJECTIVE

Differentiation of immortalized Mesenchymal Stromal Cells (iMSCs) into PDGFRα-positive cells under controlled growth conditions has several vital implications in functional studies concerned with the pathogenesis of Diabetic Gastroparesis (DGP). A study published previously by our research group demonstrated the importance of these cells as a novel, in-vitro model for investigating the functional role of neuronal nitric oxide synthase. The currently available methods require fresh differentiation of PDGFRα-positive cells for each round of experimentation. This leads to longer delays, higher usage of reagents, and inconsistency in reproducibility of experiments frequently. We thus aimed to establish through validation that cryopreserving and maintaining the iMSC-derived PDGFRα-positive cells for functional investigations help us to overcome these challenges.

RESULTS

We demonstrated for the first time that the differentiated PDGFRα-positive cells from iMSCs can be cryopreserved and thawed to be used as per the experimental requirements with prolonged preservation of their characteristics. We assessed the viability of differentiated PDGFRα-positive cells pre- and post-freezing with the subsequent validation of their functional features using flow cytometry, qRT-PCR, and western blotting. We have been successful in demonstrating for the first time that the cryopreservation of previously differentiated PDGFRα-positive cells can be used as a feasible and cost-effective model for experimental reproducibility in functional studies of Diabetes Gastroparesis.

Upper Gastrointestinal Motility, Disease and Potential of Stem Cell Therapy

Many gastrointestinal motility disorders arise due to defects in the enteric nervous system. Achalasia and gastroparesis are two extremely debilitating digestive diseases of the upper gastrointestinal tract caused in part by damage or loss of the nitrergic neurons in the esophagus and stomach. Most current pharmacological and surgical interventions provide no long-term relief from symptoms, and none address the cause. Stem cell therapy, to replace the missing neurons and restore normal gut motility, is an attractive alternative therapy. However, there are a number of hurdles that must be overcome to bring this exciting research from the bench to the bedside.

Nitric Oxide: From Gastric Motility to Gastric Dysmotility

It is known that nitric oxide (NO) plays a key physiological role in the control of gastrointestinal (GI) motor phenomena. In this respect, NO is considered as the main non-adrenergic, non-cholinergic (NANC) inhibitory neurotransmitter responsible for smooth muscle relaxation. Moreover, many substances (including hormones) have been reported to modulate NO production leading to changes in motor responses, further underlying the importance of this molecule in the control of GI motility. An impaired NO production/release has indeed been reported to be implicated in some GI dysmotility. In this article we wanted to focus on the influence of NO on gastric motility by summarizing knowledge regarding its role in both physiological and pathological conditions. The main role of NO on regulating gastric smooth muscle motor responses, with particular reference to NO synthases expression and signaling pathways, is discussed. A deeper knowledge of nitrergic mechanisms is important for a better understanding of their involvement in gastric pathophysiological conditions of hypo- or hyper-motility states and for future therapeutic approaches. A possible role of substances which, by interfering with NO production, could prove useful in managing such motor disorders has been advanced.