Integrated regulation of dopaminergic and epigenetic effectors of neuroprotection in Parkinson's disease models

Studying the mechanisms of neurodegeneration: C. elegans advantages and opportunities

Caenorhabditis elegans has been widely used as a model organism in neurodevelopment for several decades due to its simplicity, rapid growth, short life cycle, transparency, and rather simple genetics. It has been useful in modeling neurodegenerative diseases by the heterologous expression of the major proteins that form neurodegenerative-linked aggregates such as amyloid-β peptide, tau protein, and α-synuclein, among others. Furthermore, chemical treatments as well as the existence of several interference RNA libraries, transgenic worm lines, and the possibility of generating new transgenic strains create a magnificent range of possible tools to study the signaling pathways that could confer protection against protein aggregates or, on the contrary, are playing a detrimental role. In this review, we summarize the different C. elegans models of neurodegenerative diseases with a focus on Alzheimer's and Parkinson's diseases and how genetic tools could be used to dissect the signaling pathways involved in their pathogenesis mentioning several examples. Finally, we discuss the use of pharmacological agents in C. elegans models that could help to study these disease-associated signaling pathways and the powerful combinations of experimental designs with genetic tools. This review highlights the advantages of C. elegans as a valuable intermediary between in vitro and mammalian in vivo models in the development of potential new therapies.

Histamine Modulation of the Basal Ganglia Circuitry in the Motor Symptoms of Parkinson's Disease

PURPOSE OF REVIEW

Parkinson's disease (PD) is characterized by dopaminergic system dysfunction that results from the degeneration of neurons in the substantia nigra. However, studies suggest that other neurotransmitters, especially histamine, may also play a role in the development of PD.

RECENT FINDINGS

Numerous studies show that histamine levels in the basal ganglia significantly change in PD pathology, correlating with motor symptoms observed in animal models of PD. Histamine activates H1R or H4R on microglia in the substantia nigra, triggering an inflammatory response and promoting dopaminergic neuron degeneration. Additionally, histamine modulates neuronal excitability and firing activity (firing rate and pattern) by activating H1R, H2R, or H3R on neurons in the basal ganglia nucleus, ultimately impacting normal motor behavior as well as motor symptoms in models of PD.

SUMMARY

This review presents the role of histamine and its receptor ligands in the basal ganglia nuclei, along with downstream ion channels linked to histamine receptors that influence immune response, neuronal excitability, and firing activity in PD. It highlights their effects on neuronal firing and their connection to PD motor symptoms. Investigating new ligands targeting basal ganglia histamine receptors and associated ion channels may facilitate the development of novel treatments for PD.

Genomic and Transcriptomic Approaches Advance the Diagnosis and Prognosis of Neurodegenerative Diseases

Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS), represent a growing societal challenge due to their irreversible progression and significant impact on patients, caregivers, and healthcare systems. Despite advances in clinical and imaging-based diagnostics, these diseases are often detected at advanced stages, limiting the effectiveness of therapeutic interventions. Recent breakthroughs in genomic and transcriptomic technologies, including whole-genome sequencing, single-cell RNA sequencing (scRNA-seq), and CRISPR-based screens, have revolutionized the field, offering new avenues for early diagnosis and personalized prognosis. Genomic approaches have elucidated disease-specific genetic risk factors and molecular pathways, while transcriptomic studies have identified stage-specific biomarkers that correlate with disease progression and severity. Furthermore, genome-wide association studies (GWAS), polygenic risk scores (PRS), and spatial transcriptomics are enabling the stratification of patients based on their risk profiles and prognostic trajectories. Advances in functional genomics have uncovered actionable targets, such as ATXN2 in ALS and TREM2 in AD, paving the way for tailored therapeutic strategies. Despite these achievements, challenges remain in translating genomic discoveries into clinical practice due to disease heterogeneity and the complexity of neurodegenerative pathophysiology. Future integration of genetic technologies holds promise for transforming diagnostic and prognostic paradigms, offering hope for improved patient outcomes and precision medicine approaches.

ACK1/TNK2 kinase: molecular mechanisms and emerging cancer therapeutics

Activated CDC42-associated kinase 1 (ACK1), encoded by the TNK2 gene, is a cytoplasmic non-receptor tyrosine kinase whose aberrant activation correlates positively with cancer severity. Recent research has revealed the functional relevance of this oncokinase - it is an epigenetic regulator that drives cancer progression in multiple malignancies. Although ACK1 is an attractive target for therapeutic intervention, incomplete knowledge of its diverse signaling mechanisms and the lack of specific inhibitors have challenged its clinical success. We summarize recent breakthroughs in understanding ACK1 regulation and cellular signaling, and shed light on its immunomodulatory role in balancing T cell activation. We provide a comprehensive overview of preclinical, proof-of-concept studies of potent ACK1-targeting small-molecule inhibitors that are expected to enter clinical trials for cancer patients.

Cytosolic DNA sensors in neurodegenerative diseases: from physiological defenders to pathological culprits

Cytosolic DNA sensors are a group of pattern recognition receptors (PRRs) that vary in structures, molecular mechanisms, and origins but share a common function to detect intracellular microbial DNA and trigger the innate immune response like type 1 interferon production and autophagy. Cytosolic DNA sensors have been proven as indispensable defenders against the invasion of many pathogens; however, growing evidence shows that self-DNA misplacement to cytoplasm also frequently occurs in non-infectious circumstances. Accumulation of cytosolic DNA causes improper activation of cytosolic DNA sensors and triggers an abnormal autoimmune response, that significantly promotes pathological progression. Neurodegenerative diseases are a group of neurological disorders characterized by neuron loss and still lack effective treatments due to a limited understanding of pathogenesis. But current research has found a solid relationship between neurodegenerative diseases and cytosolic DNA sensing pathways. This review summarizes profiles of several major cytosolic DNA sensors and their common adaptor protein STING. It also discusses both the beneficial and detrimental roles of cytosolic DNA sensors in the genesis and progression of neurodegenerative diseases.

Mechanistic impacts of bacterial diet on dopaminergic neurodegeneration in a Caenorhabditis elegans α-synuclein model of Parkinson's disease

Failure of inherently protective cellular processes and misfolded protein-associated stress contribute to the progressive loss of dopamine (DA) neurons characteristic of Parkinson's disease (PD). A disease-modifying role for the microbiome has recently emerged in PD, representing an impetus to employ the soil-dwelling nematode, Caenorhabditis elegans, as a preclinical model to correlate changes in gene expression with neurodegeneration in transgenic animals grown on distinct bacterial food sources. Even under tightly controlled conditions, hundreds of differentially expressed genes and a robust neuroprotective response were discerned between clonal C. elegans strains overexpressing human alpha-synuclein in the DA neurons fed either one of only two subspecies of Escherichia coli. Moreover, this neuroprotection persisted in a transgenerational manner. Genetic analysis revealed a requirement for the double-stranded RNA (dsRNA)-mediated gene silencing machinery in conferring neuroprotection. In delineating the contribution of individual genes, evidence emerged for endopeptidase activity and heme-associated pathway(s) as mechanistic components for modulating dopaminergic neuroprotection.