Deconstructing the molecular genetics behind the PINK1/Parkin axis in Parkinson’s disease using Drosophila melanogaster as a model organism

Mitophagy: A Bridge Linking HMGB1 and Parkinson's Disease Using Adult Zebrafish as a Model Organism

High-mobility group box 1 (HMGB1) has been implicated as a key player in two critical factors of Parkinson's disease (PD): mitochondrial dysfunction and neuroinflammation. However, the specific role of HMGB1 in PD remains elusive. We investigated the effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration on mitochondrial dysfunction and HMGB1-associated inflammatory genes as well as locomotor activity in zebrafish, aiming to elucidate the role of HMGB1 in PD. Adult zebrafish received MPTP injections, and locomotor activity was measured at 24- and 48-h post-administration. Gene expression levels related to mitophagy (fis1, pink1, and park2) and HMGB1-mediated inflammation (hmgb1, tlr4, and nfkb) were quantified through RT-qPCR analysis. Following MPTP injection, the significant increase in transcript levels of fis1, pink1, and park2 indicated notable changes in PINK1/Parkin mitophagy, while the upregulation of hmgb1, tlr4, and nfkb genes pointed to the activation of the HMGB1/TLR4/NFκB inflammatory pathway. Furthermore, MPTP-injected zebrafish exhibited decreased locomotor activity, evident through reduced distance travelled, mean speed, and increased freezing durations. HMGB1 plays a major role in cellular processes as it is involved in both the mitophagy process and functions as a pro-inflammatory protein. MPTP administration in adult zebrafish activated mitophagy and inflammatory signaling, highlighting the significant role of HMGB1 as a mediator in both processes and further emphasizing its significant contribution to PD pathogenesis.

Psychosis in Parkinson's Disease: A Lesson from Genetics

Psychosis in Parkinson's disease (PDP) represents a common and debilitating condition that complicates Parkinson's disease (PD), mainly in the later stages. The spectrum of psychotic symptoms are heterogeneous, ranging from minor phenomena of mild illusions, passage hallucinations and sense of presence to severe psychosis consisting of visual hallucinations (and rarely, auditory and tactile or gustatory) and paranoid delusions. PDP is associated with increased caregiver stress, poorer quality of life for patients and carers, reduced survival and risk of institutionalization with a significant burden on the healthcare system. Although several risk factors for PDP development have been identified, such as aging, sleep disturbances, long history of PD, cognitive impairment, depression and visual disorders, the pathophysiology of psychosis in PD is complex and still insufficiently clarified. Additionally, several drugs used to treat PD can aggravate or even precipitate PDP. Herein, we reviewed and critically analyzed recent studies exploring the genetic architecture of psychosis in PD in order to further understand the pathophysiology of PDP, the risk factors as well as the most suitable therapeutic strategies.

Mitochondria-Related Apoptosis Regulation by Minocycline: A Study on a Transgenic Drosophila Model of Alzheimer's Disease

Alzheimer's disease (AD) is a very complicated and multifactorial neurological disorder having limited therapeutic interventions illustrated by the impairment in memory and cognitive function. Several lines of confirmation are stoutly connected with mitochondrial function perturbation as a significant causative factor in AD, while the molecular mechanisms involved in AD pathogenesis are still poorly understood. Minocycline, a well-known antibiotic, has confirmed efficacy against mitochondrial defects and oxidative stress as a neuroprotective effect. In view of this property, we examined the remedial effect of minocycline on AD. To attain insight into the molecular machinery responsible for AD pathogenesis, we preferred the UAS/GAL4 scheme for the development of AD in flies that overexpress the Aβ42 protein in the brain of Drosophila. The warning signs like the declined lifespan, locomotion deficit and memory loss, impaired mitochondrial membrane potential, and increased caspase 3 expression with mitogen-associated protein kinases linked with AD pathogenesis were examined in the existence of minocycline. Minocycline halted the Aβ42-induced symptoms including behavioral changes and altered the mitochondrial membrane potential along with apoptotic factors' protein expression (JNK/p-JNK and caspase 3). Thus, the current study could be functional to find out the role of minocycline in human Aβ42-overexpressed transgenic AD flies.