Investigating LIM (Lin-11, Isl-1, and Mec-3) Kinases and Their Correlation with Pathological Events and Microtubule Dynamics in an Experimental Model of Spinal Cord Injury in Rats

LIM kinases in cardiovascular health and disease

The Lim Kinase (LIMK) family of serine/threonine kinases is comprised of LIMK1 and LIMK2, which are central regulators of cytoskeletal dynamics via their well-characterized roles in promoting actin polymerization and destabilizing the cellular microtubular network. The LIMKs have been demonstrated to modulate several fundamental physiological processes, including cell cycle progression, cell motility and migration, and cell differentiation. These processes play important roles in maintaining cardiovascular health. However, LIMK activity in healthy and pathological states of the cardiovascular system is poorly characterized. This review highlights the cellular and molecular mechanisms involved in LIMK activation and inactivation, examining its roles in the pathophysiology of vascular and cardiac diseases such as hypertension, aneurysm, atrial fibrillation, and valvular heart disease. It addresses the LIMKs' involvement in processes that support cardiovascular health, including vasculogenesis, angiogenesis, and endothelial mechanotransduction. The review also features how LIMK activity participates in endothelial cell, vascular smooth muscle cell, and cardiomyocyte physiology and its implications in pathological states. A few recent preclinical studies demonstrate the therapeutic potential of LIMK inhibition. We conclude by proposing that future research should focus on the potential clinical relevance of LIMK inhibitors as therapeutic agents to reduce the burden of cardiovascular disease and improve patient outcomes.

Evaluating the Role of Lin-11, Isl-1, and Mec-3 Kinases in Dopaminergic Neurodegeneration in a Subacute 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine Model of Parkinson's Disease

The malfunctioning of microtubules is highly correlated with neurodegenerative disorders such as Parkinson's disease (PD), although whether it is a cause or an effect of neurodegeneration is yet unknown. Lin-11, Isl-1, and Mec-3 kinases (LIMKs), being one of the important kinases, regulate the neuronal cytoskeleton by controlling the phosphorylation of the cofilin/actin-depolymerizing factor. Recently, we showed that upregulation of phosphorylated LIMK1 (p-LIMK1) affects the microtubule dynamics in a central nervous system traumatic injury. The goal of this study is to correlate the expression of LIMK1 with dopaminergic neuron death in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of PD, one of the well-established subacute models of PD, where the neurotoxin acts via inhibition of mitochondrial complex I of the electron transport chain. Herein, we found that LIMK1 expression was increased and correlated to dopaminergic neuronal death. Finally, we demonstrated that the treatment with LIMK inhibitor BMS-5 significantly reversed the neurodegeneration, along with an upregulation of the dynamic tubulins, indicating the relevance of LIMKs and microtubule dynamics in neurodegeneration. Therefore, targeting the microtubules, an integral part of the neuronal cytoskeleton and neurite formation, can be a promising strategy to combat degeneration of dopaminergic neurons.

Modulation of the LIMK Pathway by Myricetin: A Protective Strategy Against Neurological Impairments in Spinal Cord Injury

OBJECTIVE

Spinal cord injury (SCI), one of the major disabilities concerning central nervous system injury, results in permanent tissue loss and neurological impairment. The existing therapeutic options for SCI are limited and predominantly consist of chemical compounds. In this study, we delved into the neuroprotective effects of myricetin, a natural flavonoid compound, and the underlying mechanisms, specifically in the context of SCI, utilizing an in vivo model. Previously, our investigations revealed an elevation in the phosphorylated form of Lin-11, Isl-1, and Mec-3 kinase1 (LIMK1) at chronic time points postinjury, coinciding with neuronal loss and scar formation. Our primary objective here was to assess the potential neuroprotective properties of myricetin in SCI and to ascertain if these effects were linked to LIMK inhibition, a hitherto unexamined pathway to date.

METHODS

Computational docking and molecular dynamics simulation studies were performed to assess myricetin's potential to bind with LIMK. Then, using a rat contusion model, SCI was induced and different molecular techniques (Western blot, Evans Blue assay, quantitative reverse transcription polymerase chain reaction and immunohistochemistry) were performed to determine the effects of myricetin.

RESULTS

Remarkably, computational docking models identified myricetin as having a better interaction profile with LIMK than standard. Subsequent to myricetin treatment, a significant downregulation in phosphorylated LIMK expression was observed at chronic time points. This reduction correlated with a notable decrease in glial and fibrotic scar formation, and enhanced neuroprotection indicating a positive outcome in vivo.

CONCLUSION

In summary, our findings underscore myricetin's potential as a bioactive compound capable of attenuating SCI-induced injury cascades by targeting the LIMK pathway.