A novel therapeutic strategy that may safeguard neurons and other brain cells implicated in Parkinson’s disease has been identified by investigators at the Federal University of São Paulo (UNIFESP) in Brazil. The findings from this research, conducted on murine models, have been disseminated in the scientific publication Neuropharmacology.
This investigation, facilitated by FAPESP, centered on examining the impact of a peptide designated Ac2-26, which is a constituent fragment of the Annexin A1 protein. This protein is endogenously produced by both rodent and human organisms. Prior investigations in animal subjects have substantiated the role of this molecule in modulating neuroinflammation associated with Parkinson’s disease and mitigating neuronal deterioration.
Parkinson’s disease is intricately connected to the decline of neurons responsible for the synthesis and release of dopamine, a pivotal neurotransmitter essential for motor control, motivation, reward processing, and the sensation of pleasure. As these dopaminergic neurons progressively degenerate and perish due to the pathological progression of the disease, the organism’s capacity to produce dopamine is compromised. This deficiency leads to debilitating symptoms in patients, including gait freezing and tremors.
“While this remains an experimental endeavor in its nascent stages, it presents a compelling avenue by offering an alternative approach distinct from conventional therapeutic interventions. The peptide targets neuroinflammation rather than directly replenishing dopamine levels. This distinction is significant, as neurodegenerative conditions are characterized by an inflammatory response that detrimentally affects not only neurons but also surrounding glial cells. The peptide serves to attenuate this inflammatory cascade, thereby conferring protection to the brain against cell demise,” explained Cristiane Damas Gil, the incumbent head of the Department of Morphology and Genetics at the São Paulo School of Medicine (EPM), affiliated with UNIFESP, and the principal author of the study.
Currently, there is no definitive cure for Parkinson’s disease. Therapeutic efforts are predominantly focused on managing the motor deficits that arise from dopamine depletion. Consequently, the prevailing medical strategy involves the administration of levodopa, a precursor to dopamine that exerts its effects specifically on dopaminergic neurons.
“This pharmacological agent is regarded as the benchmark treatment, delivering substantial symptomatic relief, particularly during the initial phases or in acute management scenarios, where it induces a notable amelioration of motor impairments. However, its efficacy wanes with prolonged administration, potentially precipitating the onset of motor complications and variability in the therapeutic response. Therefore, the pursuit of alternative treatment modalities for a condition as complex as Parkinson’s is of paramount importance,” elaborated Luiz Philipe de Souza Ferreira, a recipient of a FAPESP scholarship and a key contributor to the research.
The Ac2-26 peptide is a recognized anti-inflammatory agent that has undergone evaluation for the management of other pathologies, although it has not yet been translated into a commercially available medication. Furthermore, scientific evidence suggests that alterations in Annexin A1 are observed in Parkinson’s disease, and this modification is linked to cerebral inflammation and the dopaminergic neuronal pathways implicated in motor regulation.
Sex-Based Differences
To recapitulate Parkinson’s disease pathology, researchers administered a neurotoxic agent to the brains of laboratory animals, inducing neuronal loss and the characteristic symptomatology of the condition. Concurrently with the intracerebral administration, the peptide was introduced intraperitoneally (into the abdominal cavity).
The study also elucidated differential protective effects and disease progression patterns between male and female murine subjects. Following the induction of Parkinson’s-like pathology, female mice initially exhibited superior performance in motor function assessments. However, this disparity diminished over time. “This enhanced resilience was evident even in the absence of the Annexin A1 protein,” stated Gil.
Experimental evaluations were performed on animals expressing the protein and on genetically modified counterparts lacking it.
“Conversely, males displayed a more pronounced degree of neuronal loss, which facilitated a clearer evaluation of the protective effects conferred by treatment with the Ac2-26 peptide, demonstrating its capacity to shield against neurodegeneration,” noted Ferreira.
The experimental findings also revealed that the induction of the disease significantly disrupted the reproductive cycles of female subjects, underscoring the impact of Parkinson’s on the endocrine system. “This observation reinforces the necessity for sex-specific therapeutic protocols,” emphasized Ferreira.
The present research indicates that the peptide acts proactively, intervening at the initial stages of cellular damage. “Our subsequent objective is to ascertain whether the peptide possesses the capacity to reverse existing damage caused by Parkinson’s disease. If this can be definitively established, the peptide would emerge as a more promising therapeutic candidate,” concluded Gil.
