Involvement of histamine and histamine H2 receptors in nicotinamide-induced differentiation of human amniotic epithelial cells into insulin-producing cells

METTL3 promotes human amniotic epithelial stem cells differentiation into insulin-producing cells by regulation of MaFA expression

OBJECTIVE

Generating mature β-cells from stem cells remains a significant challenge in diabetes cell therapy. Human amniotic epithelial stem cells (hAESCs) have made their mark in regenerative medicine, and provide several advantages compared to other stem cells. Methyltransferase-like 3 (METTL3), an essential RNA methyltransferase participating in N6-methyladenosine (m6A) mRNA methylation, plays a critical role in the normal development of β-cells, yet its deletion in β-cells leads to β-cell dysfunction and hyperglycemia.

METHODS

In this study, we isolated and characterized hAESCs from human amniotic membranes, differentiated these hAESCs into insulin-producing cells (IPCs), and explored the role of METTL3 in such differentiation. We examined the expression of METTL3 and insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2, a decodes m6A methylation "reader") in the generated IPCs. Subsequently, we suppressed METTL3 using an inhibitor (STM2457) and overexpressed METTL3 via plasmid transfection (METTL3-OE). The differentiated STM2457 and METTL3-OE IPCs were compared to normal induction (WT) IPCs regarding the expression of β-cell markers by RT-qPCR and western blotting, immunofluorescence, C-peptide release, and glucose-stimulated insulin secretion (GSIS). Methylated RNA immunoprecipitation (MeRIP)-qPCR was used to examine the molecular mechanism underlying METTL3/m6A signaling axis in MaFA (endocrine pancreatic β-cells marker) expression. We examined the potential therapeutic uses and efficacy of IPCs through streptozotocin (STZ)-induced C57BL/6 DM.

RESULTS

Isolated hAESCs displayed all characteristics of ESCs and could generate IPCs. METTL3 and IGF2BP2 were elevated during differentiation. Overexpressing METTL3 improved the expression of β-cell markers in the final differentiated IPCs, improved C-peptide release, and demonstrated increased insulin secretion upon challenging with high glucose conditions, whereas inhibiting METTL3 attenuated these effects. Moreover, METTL3 modulated the MaFA expression in an m6A-dependent manner.

CONCLUSIONS

These findings suggest METTL3 as a promoting factor of IPCs generation, with its up-regulation potentially generating more mature IPCs for hAESCs therapy of diabetes mellitus.

Human amniotic epithelial stem cells, a potential therapeutic approach for diabetes and its related complications

The escalating diabetes prevalence has heightened interest in innovative therapeutic strategies for this disease and its complications. Human amniotic epithelial stem cells (HAESCs), originate from the innermost layer of the placenta closest to the fetus and express stem cell markers in the amniotic membrane's umbilical cord attachment area, which have garnered significant attention. This article critically examines emerging research advancements and potential application values of hAESCs in treating diabetes and its complications. Initially, we will discuss the characteristics, origin, and advantages of hAESCs in differentiating into insulin-secreting cells. Subsequently, we will focus on the potential applications of hAESCs in treating diabetes complications such as diabetic retinopathy, diabetic nephropathy, and diabetic neuropathy, etc. We will scrutinize the progress of relevant clinical studies and trials involving hAESC therapy. In conclusion, as an emerging diabetes treatment method, hAESCs exhibit immense potential and application value. Despite numerous challenges in practical application, we are confident that with scientific advancement and technological progress, hAESCs will play a pivotal role in treating diabetes and its related complications.

Histaminergic System Activity in the Central Nervous System: The Role in Neurodevelopmental and Neurodegenerative Disorders

Histamine (HA), a biogenic monoamine, exerts its pleiotropic effects through four H1R-H4R histamine receptors, which are also expressed in brain tissue. Together with the projections of HA-producing neurons located within the tuberomammillary nucleus (TMN), which innervate most areas of the brain, they constitute the histaminergic system. Thus, while remaining a mediator of the inflammatory reaction and immune system function, HA also acts as a neurotransmitter and a modulator of other neurotransmitter systems in the central nervous system (CNS). Although the detailed causes are still not fully understood, neuroinflammation seems to play a crucial role in the etiopathogenesis of both neurodevelopmental and neurodegenerative (neuropsychiatric) diseases, such as autism spectrum disorders (ASDs), attention-deficit/hyperactivity disorder (ADHD), Alzheimer's disease (AD) and Parkinson's disease (PD). Given the increasing prevalence/diagnosis of these disorders and their socioeconomic impact, the need to develop effective forms of therapy has focused researchers' attention on the brain's histaminergic activity and other related signaling pathways. This review presents the current state of knowledge concerning the involvement of HA and the histaminergic system within the CNS in the development of neurodevelopmental and neurodegenerative disorders. To this end, the roles of HA in neurotransmission, neuroinflammation, and neurodevelopment are also discussed.

Involvement of gene methylation changes in the differentiation of human amniotic epithelial cells into islet-like cell clusters

Insulin-dependent diabetes results from destruction of the insulin-producing β-cells of the pancreas. Islet cell transplantation is a promising cure for diabetes. Here, we induced human amniotic epithelial cells (hAECs) to differentiate into islet-like cell clusters by nicotinamide plus betacellulin in vitro, and further investigated the DNA methylation status by a Nimble MeDIP microarray before and after cell differentiation to shed light on the molecular mechanisms of this differentiation. In addition, 5-Aza-2'-deoxycytidine was used to investigate whether the differentiation of hAECs into islet-like cells occurred through demethylation. Purified hAECs (CK18(+)/E-cadherin(+)/CD29(+)/CD90(-)/CD34(-)/CD45(-)) were isolated from human amnia. After induction, hAECs were found to be insulin positive and sensitive to glucose, indicating successful induction to islet-like cells. The methylation status of cell cytoskeleton-related genes was down-regulated and that of negative regulation of cell adhesion-related genes was up-regulated. The methylation status of pancreas development-related genes such as HNF1α and DGAT1 was decreased in hAECs after induction. After brief demethylation, INS gene expression was up-regulated in islet-like cell clusters, suggesting that DNA methylation changes were associated with the differentiation of hAECs into islet-like cell clusters.

Establishment and characterization of immortalized human amniotic epithelial cells

Human amniotic epithelial cells (HAEs) have a low immunogenic profile and possess potent immunosuppressive properties. HAEs also have several characteristics similar to stem cells, and they are discarded after parturition. Thus, they could potentially be used in cell therapy with fewer ethical problems. HAEs have a short life, so our aim is to establish and characterize immortalized human amniotic epithelial cells (iHAEs). HAEs were introduced with viral oncogenes E6/E7 and with human telomerase reverse transcriptase (hTERT) to create iHAEs. These iHAEs have proliferated around 200 population doublings (PDs) for at least 12 months. High expression of stem cell markers (Oct 3/4, Nanog, Sox2, Klf4) and epithelial markers (CK5, CK18) were detected by immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR). These iHAEs were expanded in ultra-low-attachment dishes to form spheroids similarly to epithelial stem/precursor cells. High expression of mesenchymal (CD44, CD73, CD90, CD105) and somatic (CD24, CD29, CD271, Nestin) stem cell markers was detected by flow cytometry. The iHAEs showed adipogenic, osteogenic, neuronal, and cardiac differentiation abilities. In conclusion, the immortalization of HAEs with the characteristics of stem cells has been established, allowing these iHAEs to become useful for cell therapy and regenerative medicine.

A case study of chiropractic management of pregnancy-related heartburn with postulated fetal epigenome implications

OBJECTIVE

This case study reports on chiropractic care for pregnancy-related heartburn. The purpose of this article is to relate the benefit of chiropractic treatment for one individual, to contrast chiropractic management with the biomedical standard of care for pregnancy-related heartburn, and to point to potential epigenetic implications of the standard of care.

CLINICAL FEATURES

A 32-year-old woman who was 24 weeks pregnant presented with persistent heartburn that she was treating with ranitidine (Zantac®) and calcium carbonate (Tums®) daily at the initiation of chiropractic care.

INTERVENTION AND OUTCOME

Findings of the initial examination were thoracic intersegmental dysfunction and pain upon palpation of the diaphragm, with hypertonicity noted. Therapy localization was positive for reflexes associated with the esophagus and lower esophageal sphincter, suggesting spasms. Emotional components also were identified in association with the symptoms by the use of a mind-body therapy called NeuroEmotional Technique. The patient was treated by adjusting the thoracic spine, manually releasing the diaphragm spasms, and releasing the esophageal spasm with an activator (a small hand-held instrument that creates a percussive force). The patient was symptom-free and did not use medication after the fifth treatment. She was followed throughout the remainder of her pregnancy and was asymptomatic and required no further treatment.

CONCLUSIONS

A larger study should investigate the effectiveness of chiropractic care for the treatment of pregnancy-related heartburn.

Metabolomic study of serum from rabbits with acute acalculous cholecystitis

OBJECTIVES

(1)H-NMR is a powerful approach of metabolomics. This study aimed to apply it to detect the serum metabolites in rabbits with acute acalculous cholecystitis (AAC), and to analyze their potential roles in AAC.

METHODS

Fourteen rabbits were randomly divided into two groups, the AAC group and the CON group. In the AAC rabbit model, Escherichia coli solution was injected into the gallbladder, while same volume of saline, instead of E. coli solution, was injected into the gallbladder of the CON rabbit. General morphological, light microscopic and transmission electron microscopic observations were used to evaluate the model. Metabolic profiles of serum from rabbits with AAC were investigated through (1)H-NMR spectroscopy coupled with multivariate statistical analysis, such as principal components analysis and orthogonal partial least-squares discriminant analysis.

RESULTS

The pathohistology of gallbladders showed a significant difference between the two groups, proving the successful induction of inflammation in the gallbladders of the AAC group. The serum concentration of lipids (LDL and VLDL) increased during AAC, while the concentrations of phospholipids, lactic acid, 3-hydroxybutyric acid, lysine, citric acid, asparagine, histidine, glucose and some other small molecular metabolites decreased.

CONCLUSION

The profiling of serum metabolites in rabbits with acute acalculous cholecystitis changed significantly. These changes referred to the metabolic disturbance of carbohydrate, amino acids and lipids, inhibition of immunological functions and inflammation reaction.