Estradiol activates chloride channels via estrogen receptor-α in the cell membranes of osteoblasts

Abstract

Estrogen plays important roles in regulation of bone formation. Cl channels in the ClC family are expressed in osteoblasts and are associated with bone physiology and pathology, but the relationship between Cl channels and estrogen is not clear. In this study the action of estrogen on Cl channels was investigated in the MC3T3-E1 osteoblast cell line. Our results show that 17β-estradiol could activate a current that reversed at a potential close to the Cl equilibrium potential, with a sequence of anion selectivity of I > Br > Cl > gluconate, and was inhibited by the Cl channel blockers 5-nitro-2-(3-phenylpropylamino)-benzoate and 4,4'-diisothiocyano-2,2'-stilbene disulfonic acid. Knockdown of ClC-3 Cl channel expression by a specific small interfering RNA to ClC-3 attenuated activation of the 17β-estradiol-induced Cl current. Extracellular application of membrane-impermeable 17β-estradiol-albumin conjugates activated a similar current. The estrogen-activated Cl current could be inhibited by the estrogen receptor (ER) antagonist fulvestrant (ICI 182780). The selective ERα agonist, but not ERβ agonist, activated a Cl current similar to that induced by 17β-estradiol. Silencing ERα expression prevented activation of estrogen-induced currents. Immunofluorescence and coimmunoprecipitation experiments demonstrated that ClC-3 Cl channels and ERα were colocalized and closely related in cells. Estrogen promoted translocation of ClC-3 and ERα to the cell membrane from the nucleus. In conclusion, our findings show that Cl channels can be activated by estrogen via ERα on the cell membrane and suggest that the ClC-3 Cl channel may be one of the targets of estrogen in the regulation of osteoblast activity.

The apoptotic effect of Zoledronic acid on the nasopharyngeal carcinoma cells via ROS mediated chloride channel activation

“…Then the stock solutions were diluted to the final indicated concentrations with the isotonic bath solutions or RPMI 1640. The compositions of the isotonic bath solution and the pipette solution were described as previous study, for the isotonic bath solution (in mmol/L): 2 CaCl 2 , 0.5 MgCl 2 , 70 NaCl, 10 HEPES and 140 D‐mannitol; for the pipette solution 1.2 MgCl 2 , 1 EGTA, 10 HEPES, 140 D‐mannitol, 70 N‐methyl‐D‐glucamine chloride (NMDG‐Cl) and 2 ATP. The pH of the bath and the pipette solutions were adjusted to 7.4 and 7.25 respectively with Tris‐base.…”

“…As previously described, after established a whole cell configuration, a typical cell was held at 0 mV, and then stepped to 0, ±40, and ±80 mV repeatedly with 200‐ms pluses, and a 4‐second‐interval was between voltage pluses. When the background whole‐cell chloride currents were recorded and found to be stable for more than 3 minutes in the isotonic bath solution, the chamber was perfused with different defined experimental solutions.…”

Ion Channels in The Pathogenesis of Endometriosis: A Cutting-Edge Point of View

“…At the same time, many pathways and physiological processes lead to strict regulation of their expression and functionality [26,33,34]. A wide spectrum of hormones, including progesterone, estradiol (E2), and growth factors, are known to act as modulators of the cellular expression of different ion channels [35,36]. Moreover, the open/close gating is dynamic; indeed, it can be switched by a variety of factors, including potential membrane changes, mechanical stimuli, temperature, and chemical substances, which allows ion channels to detect changes in the intracellular and extracellular environment and activate or deactivate secondary messengers for several signaling pathways [37,38].…”

Overexpression of chloride channel-3 (ClC-3) is associated with human cervical carcinoma development and prognosis

“…Recent studies show that ClC-3 plays an active and vital role in accelerating neoplasm metastasis and may be a prognostic biomarker of tumour dissemination [11]. Oestrogen can activate expression and promote translation of the ClC-3 gene [12], and be responsible for promoting cancer growth [13]. ClC-3 abnormal expression and dysfunction may result in various pathological conditions [14].…”