VPS35 and retromer dysfunction in Parkinson's disease

HucMSCs-Derived Extracellular Vesicles Deliver RPS27A Protein to Manipulate the MDM2-P53 Axis and Ameliorate Neurological Dysfunction in Parkinson's Disease

Extracellular vesicles released from mesenchymal stem cells (MSCs-EV) have shown anti-inflammatory effects in Parkinson's disease (PD). This study was designed to assess the neuroprotective effects of human umbilical cord MSCs (hucMSCs) and the possible mechanisms involved. SH-SY5Y cells were induced with MPP+, and the impact of hucMSCs-EV on the damage to SH-SY5Y cells was examined. Mice were induced with PD-like symptoms by MPTP and the effects of hucMSCs-EV on neurological damage in mouse brain tissue were detected as well. HucMSCs-EV inhibited apoptosis and oxidative stress in MPP+-induced SH-SY5Y cells. HucMSCs-EV suppressed behavioral deficits and neuronal apoptosis in MPTP-induced mice, with an increased number of dopamine neurons in brain tissues and decreased p-alpha-syn expression in dopamine neurons. The expression of ribosomal protein S27A (RPS27A) in SH-SY5Y cells was elevated after co-culture of neurons and hucMSCs-EV, and RPS27A silencing abated the effect of hucMSCs-EV in vivo and in vitro. RPS27A bound to the MDM2 promoter, thus promoting P53 ubiquitination and degradation. MDM2 overexpression strengthened the therapeutic effect of hucMSCs-EV. We conclude that hucMSCs-EV promote the interaction between RPS27A and MDM2 by delivering RPS27A, which regulates the MDM2-P53 axis to promote degradation of P53 to ameliorate neurological damage in PD.

In Situ Labeling of Pathogenic Tau Using Photo-Affinity Chemical Probes

Tau aggregation plays a crucial role in the development of Alzheimer's disease (AD). Developing specific techniques that can isolate pathogenic tau from brain tissue is important for understanding tauopathies and advancing targeted therapies. Here, we develop photoaffinity small molecular probes and a novel method for in situ tissue labeling and investigate their activity in interacting with tau in cells and AD patient brains. Based on the reported chemical structures of tau PET tracers, we designed and synthesized two tau-specific probes, namely, Tau-2 and Tau-4. After validation in cell, mouse model, and patient brain samples, our photolabeling results suggested that Tau-2 effectively labels soluble tau in cell and mouse models, while Tau-4 selectively binds high-molecular-weight tau aggregates in late-stage AD patient brain tissues. Proteomic analysis verified the specific isolation of pathogenic tau from AD brain samples. Collectively, these findings underscore the potential of our photoaffinity probes as powerful tools for investigating tau proteins and neurofibrillary tangles in neurodegenerative diseases.

The crucial role of VPS35 and SHH in Parkinson's disease: Understanding the mechanisms behind the neurodegenerative disorder

Parkinson's disease (PD) is indeed a complex neurodegenerative disorder recognized by the progressive depletion of dopaminergic neurons in the brain, particularly in the substantia nigra region, leading to motor impairments and other symptoms. But at the molecular level, the study about PD still lacks. As the number of cases worldwide continues to increase, it is critical to focus on the cellular and molecular mechanisms of the disease's presentation and neurodegeneration to develop novel therapeutic approaches. At the molecular level, the complexity is more due to the involvement of vacuolar protein sorting 35 (VPS35) and sonic hedgehog (SHH) signaling in PD (directly or indirectly), leading to one of the most prominent hallmarks of the disease, which is an accumulation of α-synuclein. This elevated pathogenesis may result from impaired autophagy due to mutation in the case of VPS35 and impairment in SHH signaling at the molecular level. The traditional understanding of PD is marked by the disruption of dopaminergic neurons and dopaminergic signaling, which exacerbates symptoms of motor function deficits. However, the changes at the molecular level that are being disregarded also impact the overall health of the dopaminergic system. Gaining insight into these two unique mechanisms is essential to determine whether they give neuroprotection or have no effect on the health of neurons. Hence, here we tried to simplify the understanding of the role of VPS35 and SHH signaling to comprehend it in one direction.

Microglia: roles and genetic risk in Parkinson's disease

The prevalence of neurodegenerative disorders such as Parkinson's disease are increasing as world populations age. Despite this growing public health concern, the precise molecular and cellular mechanisms that culminate in neurodegeneration remain unclear. Effective treatment options for Parkinson's disease and other neurodegenerative disorders remain very limited, due in part to this uncertain disease etiology. One commonality across neurodegenerative diseases is sustained neuroinflammation, mediated in large part by microglia, the innate immune cells of the brain. Initially thought to simply react to neuron-derived pathology, genetic and functional studies in recent years suggest that microglia play a more active role in the neurodegenerative process than previously appreciated. Here, we review evidence for the roles of microglia in Parkinson's disease pathogenesis and progression, with a particular focus on microglial functions that are perturbed by disease associated genes and mutations.

Is There a Place for Lewy Bodies before and beyond Alpha-Synuclein Accumulation? Provocative Issues in Need of Solid Explanations

In the last two decades, alpha-synuclein (alpha-syn) assumed a prominent role as a major component and seeding structure of Lewy bodies (LBs). This concept is driving ongoing research on the pathophysiology of Parkinson's disease (PD). In line with this, alpha-syn is considered to be the guilty protein in the disease process, and it may be targeted through precision medicine to modify disease progression. Therefore, designing specific tools to block the aggregation and spreading of alpha-syn represents a major effort in the development of disease-modifying therapies in PD. The present article analyzes concrete evidence about the significance of alpha-syn within LBs. In this effort, some dogmas are challenged. This concerns the question of whether alpha-syn is more abundant compared with other proteins within LBs. Again, the occurrence of alpha-syn compared with non-protein constituents is scrutinized. Finally, the prominent role of alpha-syn in seeding LBs as the guilty structure causing PD is questioned. These revisited concepts may be helpful in the process of validating which proteins, organelles, and pathways are likely to be involved in the damage to meso-striatal dopamine neurons and other brain regions involved in PD.