TRPV4 mRNA is elevated in the caudate nucleus with NPH but not in Alzheimer's disease

Genetic Risk Factors in Normal Pressure Hydrocephalus: What We Know and What Is Next

Knowledge of the genetic factors in normal pressure hydrocephalus (NPH) is rapidly evolving, with significant advances in recent years. We conducted a systematic review examining genetic contributions to NPH risk. Ovid Embase, Ovid Medline, Web of Science, and Cochrane Central were searched from inception through October 14, 2024, for human studies in English reporting familial NPH cases, genetic variants associated with NPH, and associations with other neurogenetic disorders and exploring transcriptomics. Studies on secondary, obstructive, and congenital hydrocephalus were excluded, and findings were reported narratively. Of 2562 titles and abstracts screened, 56 met inclusion criteria, predominantly involving European populations. More than 30 familial cases were identified, and two cohorts found that 10%-16% of patients with NPH had relatives with NPH symptoms. Whole-genome/exome sequencing, copy-number variant analyses, and genome-wide association studies showed risk variants enriched in NPH cohorts in or near CFAP43, SFMBT1, CWH43, AK9, RXFP2, PRKD1, HAVCR1, OTOG, MYO7A, NOTCH1, SPG11, MYH13, FOXJ1, AMZ1/GNA12, and C16orf95, alongside protective variants near SLCO1A2 and MLLT10. These genes are associated with blood-brain and blood-cerebrospinal fluid barriers, cilia, and ependymal function. In addition, higher rates of pathological C9orf72 repeat expansions were observed in an NPH cohort compared with controls. NPH was also more prevalent in frontotemporal dementia cohorts without this expansion and co-occurred with myotonic dystrophy type 1 in several cases. Despite heterogeneity in outcome measures, this review highlights the genetic contribution to NPH risk. Future research should encourage collaborations for big data generation, identify genetic variants addressing diversity, and integrate clinical, environmental, and shunt-response data. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Transient receptor potential channels as an emerging target for the treatment of Alzheimer's disease: Unravelling the potential of pharmacological interventions

Alzheimer's disease (AD) is a devastating disorder with a multifaceted aetiology characterized by dementia, which later progresses to cognitive impairment. Significant efforts have been made to develop pharmacological interventions that slow down the pathogenesis of AD. However, conventional drugs have failed to satisfactorily treat AD and are more focussed towards symptomatic management. Thus, there is a gap in the literature regarding novel targets and modulators targeting them for the effective treatment of AD. Recent studies have demonstrated that modulation of transient receptor potential (TRP) channels has the potential to halt AD pathogenesis at an early stage and rescue hippocampal neurons from death. Amongst several members, TRP channels like TRPA1, TRPC6, TRPM2 and TRPV2 have shown promising results in the attenuation of neurobehavioural cognitive deficits as well as signalling pathways governing such cognitive decline. Furthermore, as these channels govern the ionic balance in the cell, their beneficial effects have also been known to maintain the homeostasis of Ca2+, which is the major culprit eliciting the vicious cycle of excitotoxicity, mitochondrial dysfunction, ROS generation and neurodegeneration. Despite such tremendous potential of TRP channel modulators, their clinical investigation remains elusive. Therefore, in the present review, we have discussed such agents in the light of TRP channels as molecular targets for the amelioration of AD both at the preclinical and clinical levels.

The impact of telomere length on the risk of idiopathic normal pressure hydrocephalus: a bidirectional Mendelian randomization study

Idiopathic normal pressure hydrocephalus (iNPH) affects mainly aged populations. The gradual shortening of telomere length (TL) is one of the hallmarks of aging. Whereas the genetic contribution of TL to the iNPH is incompletely understood. We aimed to investigate the causal relationship between TL and iNPH through the Mendelian randomization (MR) analysis. We respectively obtained 186 qualified single nucleotide polymorphisms (SNPs) of TL and 20 eligible SNPs of iNPH for MR analysis. The result of MR analysis showed that genetically predicted longer TL was significantly associated with a reduced odd of iNPH (odds ratio [OR] = 0.634 95% Confidence interval [CI] 0.447-0.899, p = 0.011). The causal association remained consistent in multivariable MR (OR = 0.530 95% CI 0.327-0.860, p = 0.010). However, there was no evidence that the iNPH was causally associated with the TL (OR = 1.000 95% CI 0.996-1.004, p = 0.955). Our study reveals a potential genetic contribution of TL to the etiology of iNPH, that is a genetically predicted increased TL might be associated with a reduced risk of iNPH.

Reduced GLP-1R availability in the caudate nucleus with Alzheimer's disease

The glucagon-like peptide-1 receptor (GLP-1R) agonists reduce glycated hemoglobin in patients with type 2 diabetes. Mounting evidence indicates that the potential of GLP-1R agonists, mimicking a 30 amino acid ligand, GLP-1, extends to the treatment of neurodegenerative conditions, with a particular focus on Alzheimer's disease (AD). However, the mechanism that underlies regulation of GLP-1R availability in the brain with AD remains poorly understood. Here, using whole transcriptome RNA-Seq of the human postmortem caudate nucleus with AD and chronic hydrocephalus (CH) in the elderly, we found that GLP-1R and select mRNAs expressed in glucose dysmetabolism and dyslipidemia were significantly altered. Furthermore, we detected human RNA indicating a deficiency in doublecortin (DCX) levels and the presence of ferroptosis in the caudate nucleus impacted by AD. Using the genome data viewer, we assessed mutability of GLP-1R and 39 other genes by two factors associated with high mutation rates in chromosomes of four species. Surprisingly, we identified that nucleotide sizes of GLP-1R transcript exceptionally differed in all four species of humans, chimpanzees, rats, and mice by up to 6-fold. Taken together, the protein network database analysis suggests that reduced GLP-1R in the aged human brain is associated with glucose dysmetabolism, ferroptosis, and reduced DCX+ neurons, that may contribute to AD.

Voluntary wheel exercise improves glymphatic clearance and ameliorates colitis-associated cognitive impairment in aged mice by inhibiting TRPV4-induced astrocytic calcium activity

BACKGROUND AND OBJECTIVES

Chronic colitis exacerbates neuroinflammation, contributing to cognitive impairment during aging, but the mechanism remains unclear. The polarity distribution of astrocytic aquaporin 4 (AQP4) is crucial for the glymphatic system, which is responsible for metabolite clearance in the brain. Physical exercise (PE) improves cognition in the aged. This study aims to investigate the protective mechanism of exercise in colitis-associated cognitive impairment.

METHODS

To establish a chronic colitis model, 18-month-old C57BL/6 J female mice received periodic oral administration of 1% wt/vol dextran sodium sulfate (DSS) in drinking water. The mice in the exercise group received four weeks of voluntary wheel exercise. High-throughput sequencing was conducted to screen for differentially expressed genes. Two-photon imaging was performed to investigate the function of the astrocytic calcium activity and in vivo intervention with TRPV4 inhibitor HC-067047. Further, GSK1016790A (GSK1), a TRPV4 agonist, was daily intraperitoneally injected during the exercise period to study the involvement of TRPV4 in PE protection. Colitis pathology was confirmed by histopathology. The novel object recognition (NOR) test, Morris water maze test (MWM), and open field test were performed to measure colitis-induced cognition and anxiety-like behavior. In vivo two-photon imaging and ex vivo imaging of fluorescent CSF tracers to evaluate the function of the glymphatic system. Immunofluorescence staining was used to detect the Aβ deposition, polarity distribution of astrocytic AQP4, and astrocytic phenotype. Serum and brain levels of the inflammatory cytokines were tested by Enzyme-linked immunosorbent assay (ELISA). The brain TUNEL assay was used to assess DNA damage. Expression of critical molecules was detected using Western blotting.

RESULTS

Voluntary exercise alleviates cognitive impairment and anxiety-like behavior in aged mice with chronic colitis, providing neuroprotection against neuronal damage and apoptosis. Additionally, voluntary exercise promotes the brain clearance of Aβ via increased glymphatic clearance. Mechanistically, exercise-induced beneficial effects may be attributed, in part, to the inhibition of TRPV4 expression and TRPV4-related calcium hyperactivity, subsequent promotion of AQP4 polarization, and modulation of astrocyte phenotype.

CONCLUSION

The present study reveals a novel role of voluntary exercise in alleviating colitis-related cognitive impairment and anxiety disorder, which is mediated by the promotion of AQP4 polarization and glymphatic clearance of Aβ via inhibition of TRPV4-induced astrocytic calcium hyperactivity.

Ventricular CSF proteomic profiles and predictors of surgical treatment outcome in chronic hydrocephalus

BACKGROUND

By applying an unbiased proteomic approach, we aimed to search for cerebrospinal fluid (CSF) protein biomarkers distinguishing between obstructive and communicating hydrocephalus in order to improve appropriate surgical selection for endoscopic third ventriculostomy vs. shunt implants. Our second study purpose was to look for potential CSF biomarkers distinguishing between patients with adult chronic hydrocephalus benefitting from surgery (responders) vs. those who did not (non-responders).

METHODS

Ventricular CSF samples were collected from 62 patients with communicating hydrocephalus and 28 patients with obstructive hydrocephalus. CSF was collected in relation to the patients' surgical treatment. As a control group, CSF was collected from ten patients with unruptured aneurysm undergoing preventive surgery (vascular clipping).

RESULTS

Mass spectrometry-based proteomic analysis of the samples identified 1251 unique proteins. No proteins differed significantly between the communicating hydrocephalus group and the obstructive hydrocephalus group. Four proteins were found to be significantly less abundant in CSF from communicating hydrocephalus patients compared to control subjects. A PCA plot revealed similar proteomic CSF profiles of obstructive and communicating hydrocephalus and control samples. For obstructive hydrocephalus, ten proteins were found to predict responders from non-responders.

CONCLUSION

Here, we show that the proteomic profile of ventricular CSF from patients with hydrocephalus differs slightly from control subjects. Furthermore, we find ten predictors of response to surgical outcome (endoscopic third ventriculostomy or ventriculo-peritoneal shunt) in patients with obstructive hydrocephalus.

X-linked hydrocephalus genes: Their proximity to telomeres and high A + T content compared to Parkinson's disease

Proximity to telomeres (i) and high adenine and thymine (A + T) content (ii) are two factors associated with high mutation rates in human chromosomes. We have previously shown that >100 human genes when mutated to cause congenital hydrocephalus (CH) meet either factor (i) or (ii) at 91% matching, while two factors are poorly satisfied in human genes associated with familial Parkinson's disease (fPD) at 59%. Using the sets of mouse, rat, and human chromosomes, we found that 7 genes associated with CH were located on the X chromosome of mice, rats, and humans. However, genes associated with fPD were in different autosomes depending on species. While the contribution of proximity to telomeres in the autosome was comparable in CH and fPD, high A + T content played a pivotal contribution in X-linked CH (43% in all three species) than in fPD (6% in rodents or 13% in humans). Low A + T content found in fPD cases suggests that PARK family genes harbor roughly 3 times higher chances of methylations in CpG sites or epigenetic changes than X-linked genes.