Poly (ADP-ribose) polymerase 1 and neurodegenerative diseases: Past, present, and future

Fibrinogen exacerbates α-synuclein aggregation and mitochondrial dysfunction via alpha5beta3 integrin in Parkinson's disease

INTRODUCTION

Blood-brain barrier(BBB) disruption promotes the influx of the fibrinogen(FG); however, it remains unknown whether FG deposit contributes to neurodegeneration in Parkinson's disease(PD).

OBJECTIVES

We aimed to examine the pathophysiologic link among FG, mitochondrial dysfunction and α-synuclein(α-syn) abnormality in PD.

METHODS

First, plasma FG levels were measured in 60 healthy controls and 60 PD patients. Second, to determine whether FG contributes to PD pathogenesis, FG was injected into the substantia nigra pars compacta(SNpc) of healthy and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-treated PD mice. Meanwhile, intraperitoneal injections of batroxobin were used to deplete FG in the brain of PD mice. Mitochondrial ultrastructure in mouse models was observed by transmission electron microscopy(TEM), and mitochondrial functions in SH-SY5Y cells were examined by different assay kits and flow cytometry. The mechanisms underlying FG-induced α-syn abnormality and mitochondrial dysfunction were observed by RNA sequencing and validated in various experiments including western blot and immunostaining. Last, the endocytosis of FG in primary neurons were detected by confocal microscopy, and α-syn aggregation after FG co-incubation were evaluated by western blot, ThT-binding assay and TEM.

RESULTS

PD patients exhibited elevated levels of FG in peripheral blood compared to HCs, and there was a positive correlation between the plasma FG and PD clinical severity. Excessive FG in the SNpc of MPTP-treated mice promoted poly (ADP-ribose) (PAR) polymerase-1(PARP1) elevation, mediated by the αvβ3 integrin receptor. FG exacerbated α-syn abnormalities and mitochondrial dysfunctions via PARP1 activation. Moreover, FG entered neurons by αvβ3 integrin mediation, potentially enhancing α-syn fibrillation and toxicity. FG facilitated α-syn aggregation subsequently reduced ATP-dependent Clp protease(ClpP) level, impairing neuronal mitochondrial unfolded response and increasing mitochondrial ROS. Pharmacological depletion of FG by batroxobin ameliorated neurodegeneration in MPTP-treated mice.

CONCLUSION

Our study indicate that FG plays an essential pathological role in α-syn abnormality. FG-targeting therapy can be a promising strategy against neurodegeneration in PD.

Exploring the role of parthanatos in CNS injury: Molecular insights and therapeutic approaches

BACKGROUND

Central nervous system (CNS) injury causes severe organ damage due to both damage resulting from the injury and subsequent cell death. However, there are currently no effective treatments for countering the irreversible loss of cell function. Parthanatos is a poly (ADP-ribose) polymerase 1 (PARP-1)-dependent form of programmed cell death that is partly responsible for neural cell death. Consequently, the mechanism by which parthanatos promotes CNS injury has attracted significant scientific interest.

AIM OF REVIEW

Our review aims to summarize the potential role of parthanatos in CNS injury and its molecular and pathophysiological mechanisms. Understanding the role of parthanatos and related molecules in CNS injury is crucial for developing effective treatment strategies and identifying important directions for future in-depth research.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Parthanatos (from Thanatos, the personification of death according to Greek mythology) is a type of programmed cell death that is initiated by the overactivation of PARP-1. This process triggers a cascade of reactions, including the accumulation of poly(ADP-ribose) (PAR), the nuclear translocation of apoptosis-inducing factor (AIF) after its release from mitochondria, and subsequent massive DNA fragmentation caused by migration inhibitory factor (MIF) forming a complex with AIF. Secondary molecular mechanisms, such as excitotoxicity and oxidative stress-induced overactivation of PARP-1, significantly exacerbate neuronal damage following initial mechanical injury to the CNS. Furthermore, parthanatos is not only associated with neuronal damage but also interacts with various other types of cell death. This review focuses on the latest research concerning the parthanatos cell death pathway, particularly considering its regulatory mechanisms and functions in CNS damage. We highlight the associations between parthanatos and different cell types involved in CNS damage and discuss potential therapeutic agents targeting the parthanatos pathway.

Proteins Associated with Neurodegenerative Diseases: Link to DNA Repair

The nervous system is susceptible to DNA damage and DNA repair defects, and if DNA damage is not repaired, neuronal cells can die, causing neurodegenerative diseases in humans. The overall picture of what is known about DNA repair mechanisms in the nervous system is still unclear. The current challenge is to use the accumulated knowledge of basic science on DNA repair to improve the treatment of neurodegenerative disorders. In this review, we summarize the current understanding of the function of DNA damage repair, in particular, the base excision repair and double-strand break repair pathways as being the most important in nervous system cells. We summarize recent data on the proteins involved in DNA repair associated with neurodegenerative diseases, with particular emphasis on PARP1 and ND-associated proteins, which are involved in DNA repair and have the ability to undergo liquid-liquid phase separation.

Targeting inflammation and gut microbiota with antibacterial therapy: Implications for central nervous system health

The complex symbiotic relationship between inflammation, the gut microbiota, and the central nervous system (CNS) has become a pivotal focus of contemporary biomedical research. Inflammation, as a physiological defense mechanism, plays a dual role as both a protective and pathological factor, and is intricately associated with gut microbiota homeostasis, often termed the "second brain." The gutbrain axis (GBA) exemplifies this multifaceted interaction, where gut health exerts significantly regulatory effects on CNS functions. Antibacterial therapies represent both promising and challenging strategies for modulating inflammation and gut microbiota composition to confer CNS benefits. However, while such therapies may exert positive modulatory effects on the gut microbiota, they also carry the potential to disrupt microbial equilibrium, potentially exacerbating neurological dysfunction. Recent advances have provided critical insights into the therapeutic implications of antibacterial interventions; nevertheless, the application of these therapies in the context of CNS health warrants a judicious and evidence-based approach. As research progresses, deeper investigation into the microbial-neural interface is essential to fully realize the potential of therapies targeting inflammation and the gut microbiota for CNS health. Future efforts should focus on refining antibacterial interventions to modulate the gut microbiota while minimizing disruption to microbial balance, thereby reducing risks and enhancing efficacy in CNS-related conditions. In conclusion, despite challenges, a more comprehensive understanding of the GBA, along with precise modulation through targeted antibacterial therapies, offers significant promise for advancing CNS disorder treatment. Continued research in this area will lead to innovative interventions and improved patient outcomes.

Parthanatos: Mechanisms, modulation, and therapeutic prospects in neurodegenerative disease and stroke

Parthanatos is a cell death signaling pathway that has emerged as a compelling target for pharmaceutical intervention. It plays a pivotal role in the neuron loss and neuroinflammation that occurs in Parkinson's Disease (PD), Alzheimer's Disease (AD), Huntington's Disease (HD), Amyotrophic Lateral Sclerosis (ALS), and stroke. There are currently no treatments available to humans to prevent cell death in any of these diseases. This review provides an in-depth examination of the current understanding of the Parthanatos mechanism, with a particular focus on its implications in neuroinflammation and various diseases discussed herein. Furthermore, we thoroughly review potential intervention targets within the Parthanatos pathway. We dissect recent progress in inhibitory strategies, complimented by a detailed structural analysis of key Parthanatos executioners, PARP-1, AIF, and MIF, along with an assessment of their established inhibitors. We hope to introduce a new perspective on the feasibility of targeting components within the Parthanatos pathway, emphasizing its potential to bring about transformative outcomes in therapeutic interventions. By delineating therapeutic opportunities and known targets, we seek to emphasize the imperative of blocking Parthanatos as a precursor to developing disease-modifying treatments. This comprehensive exploration aims to catalyze a paradigm shift in our understanding of potential neurodegenerative disease therapeutics, advocating for the pursuit of effective interventions centered around Parthanatos inhibition.

SIRT1 Regulates Mitochondrial Damage in N2a Cells Treated with the Prion Protein Fragment 106-126 via PGC-1α-TFAM-Mediated Mitochondrial Biogenesis

Mitochondrial damage is an early and key marker of neuronal damage in prion diseases. As a process involved in mitochondrial quality control, mitochondrial biogenesis regulates mitochondrial homeostasis in neurons and promotes neuron health by increasing the number of effective mitochondria in the cytoplasm. Sirtuin 1 (SIRT1) is a NAD+-dependent deacetylase that regulates neuronal mitochondrial biogenesis and quality control in neurodegenerative diseases via deacetylation of a variety of substrates. In a cellular model of prion diseases, we found that both SIRT1 protein levels and deacetylase activity decreased, and SIRT1 overexpression and activation significantly ameliorated mitochondrial morphological damage and dysfunction caused by the neurotoxic peptide PrP106-126. Moreover, we found that mitochondrial biogenesis was impaired, and SIRT1 overexpression and activation alleviated PrP106-126-induced impairment of mitochondrial biogenesis in N2a cells. Further studies in PrP106-126-treated N2a cells revealed that SIRT1 regulates mitochondrial biogenesis through the PGC-1α-TFAM pathway. Finally, we showed that resveratrol resolved PrP106-126-induced mitochondrial dysfunction and cell apoptosis by promoting mitochondrial biogenesis through activation of the SIRT1-dependent PGC-1α/TFAM signaling pathway in N2a cells. Taken together, our findings further describe SIRT1 regulation of mitochondrial biogenesis and improve our understanding of mitochondria-related pathogenesis in prion diseases. Our findings support further investigation of SIRT1 as a potential target for therapeutic intervention of prion diseases.

The Therapeutic Potential of Harpagophytum procumbens and Turnera subulata and Advances in Nutraceutical Delivery Systems in Neurodegenerative Diseases

This review article covers the therapeutic potential of the plants Harpagophytum procumbens and Turnera subulata in the treatment of neurodegenerative diseases. Despite the recognition of their beneficial properties, there is notable shortage of specific clinical and in vitro studies on these species regarding neurodegenerative diseases. Compounds such as harpagosides and vite-xin-2-O-rhamnoside, found in Harpagophytum procumbens and Turnera subulata, respectively, as well as other antioxidants and anti-inflammatory agents, are associated with mechanisms of action that involve reducing oxidative stress and modulating the inflammatory response, indicating their therapeutic potential in these pathologies. Additionally, the use of nutraceuticals derived from medicinal plants has emerged as a promising approach, offering natural therapeutic alternatives. However, the pressing need for studies focusing on the pharmacokinetics, safety, and pharmacological interactions of these extracts for the treatment of neurodegenerative diseases is emphasized. This review also evaluated advances in nutraceutical delivery systems, highlighting technological innovations that can optimize the precise delivery of these compounds to patients. Such findings highlight the gaps in the study of these plants for the treatment of neurodegenerative diseases and, at the same time, the potential for opening new perspectives in the treatment of neurodegenerative diseases, providing expectations for innovative solutions in this critical domain of medicine.

Whole organism snRNA-seq reveals systemic peripheral changes in Alzheimer's Disease fly models

Peripheral tissues become disrupted in Alzheimer's Disease (AD). However, a comprehensive understanding of how the expression of AD-associated toxic proteins, Aβ42 and Tau, in neurons impacts the periphery is lacking. Using Drosophila, a prime model organism for studying aging and neurodegeneration, we generated the Alzheimer's Disease Fly Cell Atlas (AD-FCA): whole-organism single-nucleus transcriptomes of 219 cell types from adult flies neuronally expressing human Aβ42 or Tau. In-depth analyses and functional data reveal impacts on peripheral sensory neurons by Aβ42 and on various non-neuronal peripheral tissues by Tau, including the gut, fat body, and reproductive system. This novel AD atlas provides valuable insights into potential biomarkers and the intricate interplay between the nervous system and peripheral tissues in response to AD-associated proteins.