Ras and Rab Interactor 3: From Cellular Mechanisms to Human Diseases

The Correlation Between RIN3 Gene Methylation and Cognitive Impairment in Parkinson's Disease

Background

Parkinson's disease (PD) is the second most common neurodegenerative disorder, after Alzheimer's disease. Many individuals with PD experience cognitive impairment, significantly threatening both their physical and mental well-being. Research has shown that abnormal DNA methylation is closely linked to neurodegenerative conditions such as Alzheimer's and Parkinson's disease. The RIN3 gene, which encodes a guanine nucleotide exchange factor, plays a role in inhibiting amyloid-beta formation and affects protein endocytosis, both of which are linked to cognitive impairment. However, the potential connection between RIN3 gene methylation and cognitive impairment in Parkinson's disease has not yet been explored. This study aims to explore whether the methylation status of the RIN3 gene is connected to cognitive decline in Parkinson's patients, thereby shedding light on the gene's crucial role in the disease's development and identifying potential targets for diagnosing and treating cognitive impairment in this context.

Purpose

This study aims to explore whether the methylation status of the RIN3 gene is associated with cognitive impairment in Parkinson's disease and to further clarify the gene's significant role in the disease's pathogenesis.

Methods

This study involved 50 control subjects and 51 Parkinson's disease (PD) patients, who were assessed using a cognitive scale. Additionally, DNA methylation in whole blood was analyzed. The research compared RIN3 methylation levels between the PD group and the normal control group (NC), as well as between the subgroups of PD-Mild Cognitive Impairment (PD-MCI), PD-Normal Cognition (PD-NC), and the control group.

Results

The DNA methylation level of the RIN3 gene in the whole blood of patients with PD was lower than that in healthy controls (22.3%vs.23.6%, P=0.009). Moreover, individuals with PD-MCI had significantly lower RIN3 methylation levels than both the control group (21.3%vs.23.6%, P<0.001) and those in the PD-NC group (21.3%vs.23.3%, P=0.001).

Conclusion

RIN3 methylation is associated with PD-MCI. With appropriate lifestyle changes and clinical interventions, methylation may influence disease progression, suggesting that RIN3 gene methylation could serve as a predictor for the development of PD-MCI.

Genome assemblies for Chromidotilapia guntheri (Teleostei: Cichlidae) identify a novel candidate gene for vertebrate sex determination, RIN3

Advances in genome sequencing have greatly accelerated the identification of sex chromosomes in a variety of species. Many of these species have experienced structural rearrangements that reduce recombination between the sex chromosomes, allowing the accumulation of sequence differences over many megabases. Identification of the genes that are responsible for sex determination within these sometimes large regions has proved difficult. Here, we identify an XY sex chromosome system on LG19 in the West African cichlid fish Chromidotilapia guntheri in which the region of differentiation extends over less than 400 kb. We develop high-quality male and female genome assemblies for this species, which confirm the absence of structural variants, and which facilitate the annotation of genes in the region. The peak of differentiation lies within rin3, which has experienced several debilitating mutations on the Y chromosome. We suggest two hypotheses about how these mutations might disrupt endocytosis, leading to Mendelian effects on sexual development.

The Role of RIN3 Gene in Alzheimer's Disease Pathogenesis: a Comprehensive Review

Alzheimer's disease (AD) is a globally prevalent form of dementia that impacts diverse populations and is characterized by progressive neurodegeneration and impairments in executive memory. Although the exact mechanisms underlying AD pathogenesis remain unclear, it is commonly accepted that the aggregation of misfolded proteins, such as amyloid plaques and neurofibrillary tau tangles, plays a critical role. Additionally, AD is a multifactorial condition influenced by various genetic factors and can manifest as either early-onset AD (EOAD) or late-onset AD (LOAD), each associated with specific gene variants. One gene of particular interest in both EOAD and LOAD is RIN3, a guanine nucleotide exchange factor. This gene plays a multifaceted role in AD pathogenesis. Firstly, upregulation of RIN3 can result in endosomal enlargement and dysfunction, thereby facilitating the accumulation of beta-amyloid (Aβ) peptides in the brain. Secondly, RIN3 has been shown to impact the PICLAM pathway, affecting transcytosis across the blood-brain barrier. Lastly, RIN3 has implications for immune-mediated responses, notably through its influence on the PTK2B gene. This review aims to provide a concise overview of AD and delve into the role of the RIN3 gene in its pathogenesis.

Alzheimer's Disease: Models and Molecular Mechanisms Informing Disease and Treatments

Alzheimer's Disease (AD) is a complex neurodegenerative disease resulting in progressive loss of memory, language and motor abilities caused by cortical and hippocampal degeneration. This review captures the landscape of understanding of AD pathology, diagnostics, and current therapies. Two major mechanisms direct AD pathology: (1) accumulation of amyloid β (Aβ) plaque and (2) tau-derived neurofibrillary tangles (NFT). The most common variants in the Aβ pathway in APP, PSEN1, and PSEN2 are largely responsible for early-onset AD (EOAD), while MAPT, APOE, TREM2 and ABCA7 have a modifying effect on late-onset AD (LOAD). More recent studies implicate chaperone proteins and Aβ degrading proteins in AD. Several tests, such as cognitive function, brain imaging, and cerebral spinal fluid (CSF) and blood tests, are used for AD diagnosis. Additionally, several biomarkers seem to have a unique AD specific combination of expression and could potentially be used in improved, less invasive diagnostics. In addition to genetic perturbations, environmental influences, such as altered gut microbiome signatures, affect AD. Effective AD treatments have been challenging to develop. Currently, there are several FDA approved drugs (cholinesterase inhibitors, Aß-targeting antibodies and an NMDA antagonist) that could mitigate AD rate of decline and symptoms of distress.

The Cleavage-Specific Tau 12A12mAb Exerts an Anti-Amyloidogenic Action by Modulating the Endocytic and Bioenergetic Pathways in Alzheimer's Disease Mouse Model

Beyond deficits in hippocampal-dependent episodic memory, Alzheimer's Disease (AD) features sensory impairment in visual cognition consistent with extensive neuropathology in the retina. 12A12 is a monoclonal cleavage specific antibody (mAb) that in vivo selectively neutralizes the AD-relevant, harmful N-terminal 20-22 kDa tau fragment(s) (i.e., NH₂htau) without affecting the full-length normal protein. When systemically injected into the Tg2576 mouse model overexpressing a mutant form of Amyloid Precursor Protein (APP), APPK670/671L linked to early onset familial AD, this conformation-specific tau mAb successfully reduces the NH₂htau accumulating both in their brain and retina and, thus, markedly alleviates the phenotype-associated signs. By means of a combined biochemical and metabolic experimental approach, we report that 12A12mAb downregulates the steady state expression levels of APP and Beta-Secretase 1 (BACE-1) and, thus, limits the Amyloid beta (Aβ) production both in the hippocampus and retina from this AD animal model. The local, antibody-mediated anti-amyloidogenic action is paralleled in vivo by coordinated modulation of the endocytic (BIN1, RIN3) and bioenergetic (glycolysis and L-Lactate) pathways. These findings indicate for the first time that similar molecular and metabolic retino-cerebral pathways are modulated in a coordinated fashion in response to 12A12mAb treatment to tackle the neurosensorial Aβ accumulation in AD neurodegeneration.

Update on the pathogenesis and genetics of Paget’s disease of bone

Studies over the past two decades have led to major advances in the pathogenesis of Paget’s disease of bone (PDB) and particularly on the role of genetic factors. Germline mutations of different genes have been identified, as a possible cause of this disorder, and most of the underlying pathways are implicated in the regulation of osteoclast differentiation and function, whereas other are involved in cell autophagy mechanisms. In particular, about 30 different germline mutations of the Sequestosome 1 gene (SQSTM1) have been described in a significant proportion of familial and sporadic PDB cases. The majority of SQSTM1 mutations affect the ubiquitin-binding domain of the protein and are associated to a more severe clinical expression of the disease. Also, germline mutations in the ZNF687 and PFN1 genes have been associated to severe, early onset, polyostotic PDB with increased susceptibly to neoplastic degeneration, particularly giant cell tumor. Mutations in the VCP (Valosin Containing Protein) gene cause the autosomal dominant syndrome “Inclusion Body Myopathy, PDB, Fronto-temporal Dementia,” characterized by pagetic manifestations, associated with myopathy, amyotrophic lateral sclerosis and fronto-temporal dementia. Moreover, germline mutations in the TNFRSF11A gene, which encodes for RANK, were associated with rare syndromes showing some histopathological, radiological, and clinical overlap with PDB and in two cases of early onset PDB-like disease. Likewise, genome wide association studies performed in unrelated PDB cases identified other potential predisposition genes and/or susceptibility loci. Thus, it is likely that polygenic factors are involved in the PDB pathogenesis in many individuals and that modifying genes may contribute in refining the clinical phenotype. Moreover, the contribution of somatic mutations of SQSTM1 gene and/or epigenetic mechanisms in the pathogenesis of skeletal pagetic abnormalities and eventually neoplastic degeneration, cannot be excluded. Indeed, clinical and experimental observations indicate that genetic susceptibility might not be a sufficient condition for the clinical development of PDB without the concomitant intervention of viral infection, in primis paramixoviruses, and/or other environmental factors (e.g., pesticides, heavy metals or tobacco exposure), at least in a subset of cases. This review summarizes the most important advances that have been made in the field of cellular and molecular biology PDB over the past decades.