Direct control of Na⁺-K⁺-2Cl⁻-cotransport protein (NKCC1) expression with aldosterone

Abstract

Sodium/potassium/chloride cotransporter (NKCC1) proteins play important roles in Na+ and K+ concentrations in key physiological systems, including cardiac, vascular, renal, nervous, and sensory systems. NKCC1 levels and functionality are altered in certain disease states, and tend to decline with age. A sensitive, effective way of regulating NKCC1 protein expression has significant biotherapeutic possibilities. The purpose of the present investigation was to determine if the naturally occurring hormone aldosterone (ALD) could regulate NKCC1 protein expression. Application of ALD to a human cell line (HT-29) revealed that ALD can regulate NKCC1 protein expression, quite sensitively and rapidly, independent of mRNA expression changes. Utilization of a specific inhibitor of mineralocorticoid receptors, eplerenone, implicated these receptors as part of the ALD mechanism of action. Further experiments with cycloheximide (protein synthesis inhibitor) and MG132 (proteasome inhibitor) revealed that ALD can upregulate NKCC1 by increasing protein stability, i.e., reducing ubiquitination of NKCC1. Having a procedure for controlling NKCC1 protein expression opens the doors for therapeutic interventions for diseases involving the mis-regulation or depletion of NKCC1 proteins, for example during aging.

Repeated anodal trans‐spinal direct current stimulation results in long‐term reduction of spasticity in mice with spinal cord injury

“…Both TNF‐α and MG‐132 were shown to prevent the degradation of NKCC1 (Ding et al . ; Huang et al . ; Pozdeev et al .…”

Propofol-Induced Electroencephalographic Seizures in Neonatal Rats

“…Propofol may further decrease the KCC2/NKCC1 ratio by elevating systemic levels of aldosterone, which increases NKCC1 protein expression via a rapid mechanism that does not involve changes in mRNA expression. 35 Importantly, prematurely born low birth weight neonates have elevated systemic levels of aldosterone even without exposure to general anesthetics. 36 Clinical reports that support the presence of excessive GABA A R-mediated neuronal excitability are that bumetanide reduced seizures in a 6-week-old baby with intractable multifocal seizures 37 and alleviated symptoms in 3–11 year old children with autism or Asperger syndrome, 38 disease states that are characterized by abnormal excitation/inhibition ratio in the brain.…”

Effects of Long-Term Exercise on Age-Related Hearing Loss in Mice

“…Experiments were performed in accordance with protocols approved by the University of Florida Institutional Animal Care and Use Committee. The CBA/CaJ mouse strain displays late-onset AHL by 18 -20 months of age and is a widely used model of AHL (Zheng et al, 1999;Noben-Trauth et al, 2003). Because it is well documented that regular physical exercise reduces the risk for a variety of age-associated conditions and increases life expectancy in both men and women (Taylor et al, 2004;Arem et al, 2015), male littermates were used in the current study.…”

“…The auditory function of CBA/CaJ mice is normal in early life, but declines gradually in later life (Zheng et al, 1999;Frisina and Zhu, 2010). To investigate whether long-term voluntary WR delays AHL, we conducted ABR hearing tests in control and WR CBA/ CaJ mice at 3 and 24 months of age.…”

“…However, there is currently no direct evidence that regular physical activity can slow AHL in laboratory animals or humans. The objective of the current study was to examine the effects of longterm voluntary WR on AHL in CBA/CaJ mice, a well established model of AHL (Zheng et al, 1999).…”