Leucine-Rich Repeat Kinase 2 (LRRK2) is a large, multidomain protein with dual kinase and GTPase function that is commonly mutated in both familial and idiopathic Parkinson’s Disease (PD). While dimerization of LRRK2 is commonly detected in PD models, it remains unclear whether inhibition of dimerization can regulate catalytic activity and pathogenesis. Here, we show constrained peptides that are cell-penetrant, bind LRRK2, and inhibit LRRK2 activation by downregulating dimerization. We further show that inhibited dimerization decreases kinase activity and inhibits ROS production and PD-linked apoptosis in primary cortical neurons. While many ATP-competitive LRRK2 inhibitors induce toxicity and mislocalization of the protein in cells, these constrained peptides were found to not affect LRRK2 localization. The ability of these peptides to inhibit pathogenic LRRK2 kinase activity suggests that disruption of dimerization may serve as a new allosteric strategy to downregulate PD-related signaling pathways.

Mutations in the gene coding for leucine-rich repeat kinase 2 (LRRK2) are a leading cause of the inherited form of Parkinson’s disease (PD), while LRRK2 overactivation is also associated with the more common idiopathic form of PD. LRRK2 is a large multidomain protein, including a GTPase as well as a Ser/Thr protein kinase domain. Common, disease-causing mutations increase LRRK2 kinase activity, presenting LRRK2 as an attractive target for drug discovery. Currently, drug development has mainly focused on ATP-competitive kinase inhibitors. Here, we report the identification and characterization of a variety of nanobodies that bind to different LRRK2 domains and inhibit or activate LRRK2 in cells and in in vitro. Importantly, nanobodies were identified that inhibit LRRK2 kinase activity while binding to a site that is topographically distinct from the active site and thus act through an allosteric inhibitory mechanism that does not involve binding to the ATP pocket or even to the kinase domain. Moreover, while certain nanobodies completely inhibit the LRRK2 kinase activity, we also identified nanobodies that specifically inhibit the phosphorylation of Rab protein substrates. Finally, in contrast to current type I kinase inhibitors, the studied kinase-inhibitory nanobodies did not induce LRRK2 microtubule association. These comprehensively characterized nanobodies represent versatile tools to study the LRRK2 function and mechanism and can pave the way toward novel diagnostic and therapeutic strategies for PD.

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Parkinson's disease (PD) is the second most common neurodegenerative disease. In recent years, it has been shown that leucine-rich repeat kinase 2 (LRRK2) has a crucial function in both familial and sporadic forms of PD. LRRK2 pathogenic mutations are thought to result in an increase in LRRK2 kinase activity. Thus, inhibiting LRRK2 kinase activity has become a main therapeutic target. Many compounds capable of inhibiting LRRK2 kinase activity with high selectivity and brain availability have been described. However, the safety of long-term use of these ATP-competitive LRRK2 kinase inhibitors has been challenged by several studies. Therefore, alternative ways of targeting LRRK2 activity will have a great benefit. In this review, we discuss the recent progress in the development of allosteric inhibitors of LRRK2, mainly via interfering with GTPase activity, and propose potential new intra and interprotein interactions targets that can lead to open doors toward new therapeutics.

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Deltamethrin (DLM) is a synthetic pyrethroid with anti-acaricide and insecticidal properties. It is commonly used in agriculture and veterinary medicine. Humans and animals are exposed to DLM through the ingestion of polluted food and water, resulting in severe health issues. N-acetylcysteine (NAC) is a prodrug of L-cysteine, the precursor to glutathione. It can restore the oxidant-antioxidant balance. Therefore, this research aimed to examine whether NAC may protect broiler chickens against oxidative stress, at the level of biochemical and molecular alterations caused by DLM intoxication. The indicators of liver and kidney injury in the serum of DLM-intoxicated and NAC-treated groups were examined. Furthermore, lipid peroxidation, antioxidant markers, superoxide dismutase activity, and apoptotic gene expressions (caspase-3 and Bcl-2) were investigated. All parameters were significantly altered in the DLM-intoxicated group, suggesting that DLM could induce oxidative damage and apoptosis in hepato-renal tissue. The majority of the changes in the studied parameters were reversed when NAC therapy was used. In conclusion, by virtue of its antioxidant and antiapoptotic properties, NAC enabled the provision of significant protection effects against DLM-induced hepato-renal injury.

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A total number of 72 New Zealand White (NZW) growing rabbits of mixed sex, 6 weeks old of about 500±13.75 g average body weight were used to study the effect of different levels of Moringa stems without or with supplementation of caplix enzyme on rabbit performance, nutrients digestibility coefficient, caecum activity, carcass characteristics and economic efficiency. Rabbits were divided into 6 treatments; each containing 12 rabbits in 4 replicates (3 rabbits in each). Three substitution levels of Moringa stems, as well as, two levels without or with caplix were used in 3×2 factorial arrangement. Moringa stems levels were zero (control), 25 and 50% instead of clover straw of the control diet, while the levels of caplix were 0 or 0.05% of diet. The experimental period was extended to 8 weeks.These results obtained indicated that, replacing Moringa stems for clover straw at 25 and 50% in rabbit diets significantly (P<0.05) improved CP, EE, CF, NDF, ADF and ADL digestibility as will as DCP and TDN values compared to the control group. Also, adding caplix to rabbit diets improved (P<0.05) these nutrients digestibility as compared to the groups fed diets without caplix. Replacing Moringa stems by clover straw at 25 and 50% or adding caplix to rabbit diets resulted in an improvement (P< 0.05) of caecum pH and an increase (P<0.05) in caecal VFA ̕ S