Ethanol impairs microtubule formation via interactions at a microtubule associated protein-sensitive site

Abstract

Prolonged ethanol abuse has been associated with brain injury caused by impaired synaptogenesis, cellular migration, neurogenesis, and cell signaling, all of which require proper microtubule functioning. However, the means by which ethanol may impair microtubule formation or function and the role that microtubule-associated proteins (MAPs) have in mediating such effects are not clear. In the present studies, purified MAP-deficient (2 mg/mL) and MAP-rich (pre-conjugated; 1 mg/mL) bovine α/β tubulin dimer were allowed to polymerize at 37 °C, forming microtubules in the presence or absence of ethanol (25–500 mM). Microtubule formation was assessed in a 96-well format using a turbidity assay, with absorption measured at 340 nm for 45 min. Additional studies co-exposed α/β tubulin dimers to 50 mM ethanol and purified MAPs (0.1 mg/mL) for 45 min. Polymerization of MAP-deficient tubulin was significantly decreased (at 15–45 min of polymerization) during exposure to ethanol (> 25 mM). In contrast, ethanol exposure did not alter polymerization of α/β tubulin dimers pre-conjugated to MAPs, at any concentration. Concurrent exposure of MAP-deficient tubulin with purified MAPs and ethanol resulted in significant and time-dependent decreases in tubulin polymerization, with recovery from inhibition at later time points. The present results suggest that ethanol disrupts MAP-independent microtubule formation and MAP-dependent microtubule formation via direct actions at a MAP-sensitive microtubule residue, indicating that disruption of neuronal microtubule formation and function may contribute to the neurodegenerative effects of binge-like ethanol intake.

The Loss of α- and β-Tubulin Proteins Are a Pathological Hallmark of Chronic Alcohol Consumption and Natural Brain Ageing

“…Furthermore, we show that tubulin reductions were observed in our rat model of 4 weeks of alcohol administration, indicating a robust pathological hallmark. In support of our findings, other independent studies have also detected a reduction of α- and β-tubulin levels in human alcoholics [ 60 ], reduced tubulin levels in primary neurons [ 50 ], and an ethanol-induced disruption of microtubule function and polymerisation [ 61 ].…”

Chronic binge alcohol consumption alters myogenic gene expression and reduces in vitro myogenic differentiation potential of myoblasts from rhesus macaques

“…Little attention has been directed to the function of adult muscle stem cells, satellite cells (SCs), in alcohol-induced myopathies. Because alcohol has been shown to impair stem cell function in other tissues, including the brain, liver, and bone marrow (2,10,31,38), we hypothesized that together with an impairment of anabolic and catabolic pathways, alcohol's adverse effect on muscle mass and function also involves dysregulation of SC function to form new myofibers.…”

Effect of ethanol and cocaine on [11C]MPC-6827 uptake in SH-SY5Y cells

“…MTs are hetero-dimer units formed from α-and β-tubulin monomers [1]. Essential biophysical functions, including cellular signaling and axoplasmic transport, depend on the structural integrity of MTs i.e., polymerization with bound and free tubulin units and MT integrity is heavily dysregulated in AUD and SUDs [2][3][4][5]. Addictive behaviors lead to many adaptations in postsynaptic spine structure that result in profound alterations in synaptic transmission [6].…”