Loss of cholinergic receptor muscarinic 1 impairs cortical mitochondrial structure and function: implications in Alzheimer's disease

Anti-ageing mechanism of topical bioactive ingredient composition on skin based on network pharmacology

OBJECTIVE

To elucidate the anti-ageing mechanism of the combination of eight ingredients on the skin from a multidimensional view of the skin.

METHODS

The target pathway mechanisms of composition to delay skin ageing were investigated by a network pharmacology approach and experimentally validated at three levels: epidermal, dermal, and tissue.

RESULTS

We identified 24 statistically significant skin ageing-related pathways, encompassing crucial processes such as epidermal barrier repair, dermal collagen and elastin production, inhibition of reactive oxygen species (ROS), as well as modulation of acetylcholine and acetylcholine receptor binding. Furthermore, our in vitro experimental findings exhibited the following outcomes: the composition promotes fibroblast proliferation and the expression of barrier-related genes in the epidermis; it also stimulated the expression of collagen I, collagen III, and elastic fibre while inhibiting ROS and β-Gal levels in HDF cells within the dermis. Additionally, Spilanthol in the Acmella oleracea extract contained in the composition demonstrated neuro-relaxing activity in Zebrafish embryo, suggesting its potential as an anti-wrinkle ingredient at the hypodermis level.

CONCLUSIONS

In vitro experiments validated the anti-ageing mechanism of composition at multiple skin levels. This framework can be extended to unravel the functional mechanisms of other clinically validated compositions, including traditional folk recipes utilized in cosmeceuticals.

Muscarinic Receptors and Alzheimer's Disease: New Perspectives and Mechanisms

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases on a global scale. Historically, this pathology has been linked to cholinergic transmission, and despite the scarcity of effective therapies, numerous alternative processes and targets have been proposed as potential avenues for comprehending this complex illness. Nevertheless, the fundamental pathophysiological mechanisms underpinning AD remain largely enigmatic, with a growing body of evidence advocating for the significance of muscarinic receptors in modulating the brain's capacity to adapt and generate new memories. This review summarizes the current state of the art in the field of muscarinic receptors' involvement in AD. A specific key factor was the relationship between comorbidity and the emergence of new mechanisms.

Associations of genetic variations in the M3 receptor with salt sensitivity, longitudinal changes in blood pressure and the incidence of hypertension in Chinese adults

Recent studies have reported the role of the M3 muscarinic acetylcholine receptor (M3R), a member of the G-protein coupled receptor superfamily, encoded by the CHRM3 gene, in cardiac function and the regulation of blood pressure (BP). The aim of this study was to investigate the associations of CHRM3 genetic variants with salt sensitivity, longitudinal BP changes, and the development of hypertension in a Chinese population. We conducted a chronic dietary salt intervention experiment in a previously established Chinese cohort to analyze salt sensitivity of BP. Additionally, a 14-year follow-up was conducted on all participants in the cohort to evaluate the associations of CHRM3 polymorphisms with longitudinal BP changes, as well as the incidence of hypertension. The single nucleotide polymorphism (SNP) rs10802811 within the CHRM3 gene displayed significant associations with low salt-induced changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP), while rs373288072, rs114677844, and rs663148 exhibited significant associations with SBP and MAP responses to a high-salt diet. Furthermore, the SNP rs58359377 was associated with changes in SBP and pulse pressure (PP) over the course of 14 years. Additionally, the 14-year follow-up revealed a significant association between the rs619288 polymorphism and an increased risk of hypertension (OR = 1.74, 95% CI: 1.06-2.87, p = .029). This study provides evidence that CHRM3 may have a role in salt sensitivity, BP progression, and the development of hypertension.

Cholinergic Receptor Muscarinic 1 Co-Localized with Mitochondria in Cultured Dorsal Root Ganglion Neurons, and Its Deletion Disrupted Mitochondrial Ultrastructure in Peripheral Neurons: Implications in Alzheimer's Disease

Background

Loss of Cholinergic Receptor Muscarinic 1 (CHRM1) has been linked to the pathogenesis of Alzheimer's disease (AD). Our recent study found significantly lower CHRM1 protein levels in AD patient cortices, linked to reduced survival. Furthermore, using knockout mice (Chrm1-/-) we demonstrated that deletion of Chrm1 alters cortical mitochondrial structure and function, directly establishing a connection between its loss and mitochondrial dysfunction in the context of AD. While CHRM1's role in the brain has been extensively investigated, its impact on peripheral neurons in AD remains a crucial area of research, especially considering reported declines in peripheral nerve conduction among AD patients.

Objective

The objective was to characterize Chrm1 localization and mitochondrial deficits in Chrm1-/- dorsal root ganglion (DRG) neurons.

Methods

Recombinant proteins tagged with Green or Red Fluorescent Protein (GFP/RFP) were transiently expressed to investigate the localization of Chrm1 and mitochondria, as well as mitochondrial movement in the neurites of cultured primary mouse DRG neurons, using confocal time-lapse live cell imaging. Transmission electron microscopy was performed to examine the ultrastructure of mitochondria in both wild-type and Chrm1-/- DRGs.

Results

Fluorescence imaging revealed colocalization and comigration of N-terminal GFP-tagged Chrm1 and mitochondrial localization signal peptide-tagged RFP-labelled mitochondria in the DRGs neurons. A spectrum of mitochondrial structural abnormalities, including disruption and loss of cristae was observed in 87% neurons in Chrm1-/- DRGs.

Conclusions

This study suggests that Chrm1 may be localized in the neuronal mitochondria and loss of Chrm1 in peripheral neurons causes sever mitochondrial structural aberrations resembling AD pathology.