The role of the PLA2G6 gene in neurodegenerative diseases

Unveiling novel susceptibility genes and drug targets for basal cell carcinoma by a cross-tissue transcriptome-wide association study

OBJECTIVE

To identify novel susceptibility genes and drug targets for basal cell carcinoma (BCC).

METHODS

We performed a transcriptome-wide association study (TWAS) to identified the susceptibility genes and potential drug targets for BCC. The cross-tissue TWAS was conducted to discover the candidate genes for BCC. Functional Summary-based Imputation (FUSION) analysis was used to validate these genes in the single tissues. Multimarker Analysis of Genomic Annotation (MAGMA) was employed to further screen candidate genes. Summary data-based Mendelian randomization (SMR) and colocalization analyses were applied to infer causal relationships between candidate genes and BCC. The expression pattern of the identified genes in single-cell types was also investigated. Function, pathway enrichment and disease connection analyses were performed to understand the biological implication of identified genes. Additionally, druggability of the identified genes was evaluated to discover potential candidate drugs for BCC.

RESULTS

Ninety-five genes were identified by cross-tissue TWAS analysis. Among them, 24 genes were confirmed by FUSION and MAGMA methods. Ten genes were further confirmed by SMR and colocalization analyses. Three genes were replicated by using another GWAS data. The potential interacting gene networks constructed with these identified genes were mainly involved in viral life cycle-HIV-1, GABAergic synapse, nicotine addiction, ether lipid metabolism, and mineral absorption pathways. AN-9 and amooranin might be candidate drugs for BCC.

CONCLUSIONS

We have identified 10 susceptibility genes associated with BCC risk, which might deepen our comprehension of BCC pathogenesis and illuminating new avenues for therapeutic and preventive drug development.

From onset to advancement: the temporal spectrum of α-synuclein in synucleinopathies

This review provides an in-depth analysis of the complex role of alpha-synuclein (α-Syn) in the development of α-synucleinopathies, with a particular focus on its structural diversity and the resulting clinical variability. The ability of α-Syn to form different strains or polymorphs and undergo various post-translational modifications significantly contributes to the wide range of symptoms observed in disorders such as Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), as well as in lesser-known non-classical α-synucleinopathies. The interaction between genetic predispositions and environmental factors further complicates α-synucleinopathic disease pathogenesis, influencing the disease-specific onset and progression. Despite their common pathological hallmark of α-Syn accumulation, the clinical presentation and progression of α-synucleinopathies differ significantly, posing challenges for diagnosis and treatment. The intricacies of α-Syn pathology highlight the critical need for a deeper understanding of its biological functions and interactions within the neuronal environment to develop targeted therapeutic strategies. The precise point at which α-Syn aggregation transitions from being a byproduct of initial disease triggers to an active and independent driver of disease progression - through the propagation and acceleration of pathogenic processes - remains unclear. By examining the role of α-Syn across various contexts, we illuminate its dual role as both a marker and a mediator of disease, offering insights that could lead to innovative approaches for managing α-synucleinopathies.

Novel PNPLA8 variants associated with primary ovarian insufficiency, tremors, cerebellar ataxia and limb weakness: a case report and literature review

BACKGROUND

PNPLA8 is a gene that causes an autosomal recessive mitochondrial disease characterised by microcephaly and intractable epilepsy in infants and cerebellar ataxia and limb weakness in adults. Herein, we report the clinical, muscle pathology, and brain imaging features of an adult patient with new variants of PNPLA8.

METHODS

A 27-year-old Chinese woman presented with abnormal gait at age 11, remained amenorrhoeic with an infantile uterus at age 17, and presented with head and limb tremors at age 21. The results of brain magnetic resonance imaging suggested mild cerebellar atrophy. Whole-exome sequencing was performed, and mitochondrial and spinal cerebellar ataxia genes were screened. In addition, a biceps muscle biopsy was performed. Furthermore, a comprehensive literature search was conducted, and all patients with detailed clinical and genetic data up to October 2024 were included in the analysis.

RESULTS

The patient's genetic screening revealed compound heterozygous variants c.1777T > G (p.Tyr593Asp) and c.1515-1516delTT (p.Tyr506Serfs*27) of PNPLA8 inherited from her parents. Her muscle biopsy showed mild myopathic changes on light microscopy and mitochondrial inclusions on electron microscopy. A total of 25 patients from 21 families were reviewed.

CONCLUSION

Age of onset is a very important factor in terms of patient clinical phenotype and prognosis of PNPLA8-related disorders. It has been observed that adult females with PNPLA8 variants may present with primary ovarian dysfunction. The presence of mitochondrial inclusion bodies may serve as a pathological hallmark, extending the existing spectrum of the clinical phenotypes and pathogenic variants of PNPLA8.

CADASIL: A NOTCH3-associated cerebral small vessel disease

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common hereditary cerebral small vessel disease (CSVD), pathologically characterized by a non-atherosclerotic and non-amyloid diffuse angiopathy primarily involving small to medium-sized penetrating arteries and leptomeningeal arteries. In 1996, mutation in the notch receptor 3 gene (NOTCH3) was identified as the cause of CADASIL. However, since that time other genetic CSVDs have been described, including the HtrA serine peptidase 1 gene-associated CSVD and the cathepsin A gene-associated CSVD, that clinically mimic the original phenotype. Though NOTCH3-associated CSVD is now a well-recognized hereditary disorder and the number of studies investigating this disease is increasing, the role of NOTCH3 in the pathogenesis of CADASIL remains elusive.

AIM OF REVIEW

This review aims to provide insights into the pathogenesis and the diagnosis of hereditary CSVDs, as well as personalized therapy, predictive approach, and targeted prevention. In this review, we summarize the current progress in CADASIL, including the clinical, neuroimaging, pathological, genetic, diagnostic, and therapeutic aspects, as well as differential diagnosis, in which the role of NOTCH3 mutations is highlighted.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this review, CADASIL is revisited as a NOTCH3-associated CSVD along with other hereditary CSVDs.

iPLA2β loss leads to age-related cognitive decline and neuroinflammation by disrupting neuronal mitophagy

BACKGROUND

During brain aging, disturbances in neuronal phospholipid metabolism result in impaired cognitive function and dysregulation of neurological processes. Mutations in iPLA2β are associated with neurodegenerative conditions that significantly impact brain phospholipids. iPLA2β deficiency exacerbates mitochondrial dysfunction and abnormal mitochondrial accumulation. We hypothesized that iPLA2β contributes to age-related cognitive decline by disrupting neuronal mitophagy.

METHODOLOGY

We used aged wild-type (WT) mice and iPLA2β-/- mice as natural aging models to assess cognitive performance, iPLA2β expression in the cortex, levels of chemokines and inflammatory cytokines, and mitochondrial dysfunction, with a specific focus on mitophagy and the mitochondrial phospholipid profile. To further elucidate the role of iPLA2β, we employed adeno-associated virus (AAV)-mediated iPLA2β overexpression in aged mice and re-evaluated these parameters.

RESULTS

Our findings revealed a significant reduction in iPLA2β levels in the prefrontal cortex of aged brains. Notably, iPLA2β-deficient mice exhibited impaired learning and memory. Loss of iPLA2β in the PFC of aged mice led to increased levels of chemokines and inflammatory cytokines. This damage was associated with altered mitochondrial morphology, reduced ATP levels due to dysregulation of the parkin-independent mitophagy pathway, and changes in the mitochondrial phospholipid profile. AAV-mediated overexpression of iPLA2β alleviated age-related parkin-independent mitophagy pathway dysregulation in primary neurons and the PFC of aged mice, reduced inflammation, and improved cognitive function.

CONCLUSIONS

Our study suggests that age-related iPLA2β loss in the PFC leads to cognitive decline through the disruption of mitophagy. These findings highlight the potential of targeting iPLA2β to ameliorate age-related neurocognitive disorders.

An end-to-end deep learning method for mass spectrometry data analysis to reveal disease-specific metabolic profiles

Untargeted metabolomic analysis using mass spectrometry provides comprehensive metabolic profiling, but its medical application faces challenges of complex data processing, high inter-batch variability, and unidentified metabolites. Here, we present DeepMSProfiler, an explainable deep-learning-based method, enabling end-to-end analysis on raw metabolic signals with output of high accuracy and reliability. Using cross-hospital 859 human serum samples from lung adenocarcinoma, benign lung nodules, and healthy individuals, DeepMSProfiler successfully differentiates the metabolomic profiles of different groups (AUC 0.99) and detects early-stage lung adenocarcinoma (accuracy 0.961). Model flow and ablation experiments demonstrate that DeepMSProfiler overcomes inter-hospital variability and effects of unknown metabolites signals. Our ensemble strategy removes background-category phenomena in multi-classification deep-learning models, and the novel interpretability enables direct access to disease-related metabolite-protein networks. Further applying to lipid metabolomic data unveils correlations of important metabolites and proteins. Overall, DeepMSProfiler offers a straightforward and reliable method for disease diagnosis and mechanism discovery, enhancing its broad applicability.

Iron Dyshomeostasis in Neurodegeneration with Brain Iron Accumulation (NBIA): Is It the Cause or the Effect?

Iron is an essential metal ion implicated in several cellular processes. However, the reactive nature of iron renders this metal ion potentially dangerous for cells, and its levels need to be tightly controlled. Alterations in the intracellular concentration of iron are associated with different neuropathological conditions, including neurodegeneration with brain iron accumulation (NBIA). As the name suggests, NBIA encompasses a class of rare and still poorly investigated neurodegenerative disorders characterized by an abnormal accumulation of iron in the brain. NBIA is mostly a genetic pathology, and to date, 10 genes have been linked to familial forms of NBIA. In the present review, after the description of the principal mechanisms implicated in iron homeostasis, we summarize the research data concerning the pathological mechanisms underlying the genetic forms of NBIA and discuss the potential involvement of iron in such processes. The picture that emerges is that, while iron overload can contribute to the pathogenesis of NBIA, it does not seem to be the causal factor in most forms of the pathology. The onset of these pathologies is rather caused by a combination of processes involving the interplay between lipid metabolism, mitochondrial functions, and autophagic activity, eventually leading to iron dyshomeostasis.

The molecular mechanism of ferroptosis and its relationship with Parkinson's disease

Neurodegenerative diseases such as Parkinson's disease (PD) have complex pathogenetic mechanisms. Genetic, age, and environmental factors are all related to PD. Due to the unclear pathogenesis of PD and the lack of effective cure methods, it is urgent to find new targets for treating PD patients. Ferroptosis is a form of cell death that is reliant on iron and exhibits distinct morphological and mechanistic characteristics compared to other types of cell death. It encompasses a range of biological processes, including iron/lipid metabolism and oxidative stress. In recent years, research has found that ferroptosis plays a crucial role in the pathophysiological processes of neurodegenerative diseases and stroke. Therefore, ferroptosis is also closely related to PD, This article reviews the core mechanisms of ferroptosis and elucidates the correlation between PD and ferroptosis. In addition, new compounds that have emerged in recent years to exert anti PD effects by inhibiting the ferroptosis signaling pathway were summarized. I hope to further elaborate the relationship between ferroptosis and PD through the review of this article, and provide new strategies for developing PD treatments targeting ferroptosis.

A novel variant of PLA2G6 gene related early-onset parkinsonism: a case report and literature review

This study reported a case of early-onset parkinsonism associated with a novel variant of the PLA2G6 gene. The boy first started showing symptoms at the age of 11, with gait instability and frequent falls. As the disease progressed, his gait instability worsened, and he developed difficulties with swallowing and speaking, although there was no apparent decline in cognitive function. An MRI of the head revealed significant atrophy of the cerebellum. The initial diagnosis for the boy was early-onset parkinsonism, classified as Hoehn-Yahr grade 5.Genomic sequencing of the patient indicated that he had compound heterozygous variations in the PLA2G6 gene: c.1454G>A (p.Gly485Glu) and c.991G>T (p.Asp331Tyr). Pedigree analysis revealed that his younger brother also carried the same variant, albeit with milder symptoms. The patient's unaffected mother was found to be a carrier of the c.991G>T variant. Additionally, this study reviewed 62 unrelated families with PLA2G6 gene-related early-onset parkinsonism. The analysis showed a higher proportion of female probands, with a mean age of onset of ~23.0 years. Primary symptoms were predominantly bradykinesia and psychosis, with tremors being relatively rare. Cerebellar atrophy was observed in 41 patients (66.1%). Among the reported mutations, the most common mutation was c.991G>T, presenting in 21 families (33.9%), followed by c.2222G>A in eight families (12.9%). Other mutations were less common. Notably, the c.991G>T mutation was exclusive to Chinese families and was a prevalent mutation among this population. The initial symptoms varied significantly among patients with different mutations.

Functional roles of circular RNAs in lung injury

Lung injury leads to respiratory dysfunction, low quality of life, and even life-threatening conditions. Circular RNAs (circRNAs) are endogenous RNAs produced by selective RNA splicing. Studies have reported their involvement in the progression of lung injury. Understanding the roles of circRNAs in lung injury may aid in elucidating the underlying mechanisms and provide new therapeutic targets. Thus, in this review, we aimed to summarize and discuss the characteristics and biological functions of circRNAs, and their roles in lung injury from existing research, to provide a theoretical basis for the use of circRNAs as a diagnostic and therapeutic target for lung injury.