TMEM16B regulates anxiety-related behavior and GABAergic neuronal signaling in the central lateral amygdala

Abstract

TMEM16B (ANO2) is the Ca2+-activated chloride channel expressed in multiple brain regions, including the amygdala. Here we report that Ano2 knockout mice exhibit impaired anxiety-related behaviors and context-independent fear memory, thus implicating TMEM16B in anxiety modulation. We found that TMEM16B is expressed in somatostatin-positive (SOM+) GABAergic neurons of the central lateral amygdala (CeL), and its activity modulates action potential duration and inhibitory postsynaptic current (IPSC). We further provide evidence for TMEM16B actions not only in the soma but also in the presynaptic nerve terminals of GABAergic neurons. Our study reveals an intriguing role for TMEM16B in context-independent but not context-dependent fear memory, and supports the notion that dysfunction of the amygdala contributes to anxiety-related behaviors.

Molecular underpinning of intracellular pH regulation on TMEM16F

“…Having shown that pH i can regulate TMEM16F ion channel activity, we next sought to examine whether pH i can also influence TMEM16F lipid scrambling activity. In order to quantify TMEM16F lipid scrambling in different pH i , we established a modified fluorescence imaging assay (Le, Le and Yang, 2019; T. Le et al ., 2019) to overcome the difficulties in precisely controlling pH i and Ca 2+ i (Fig. 2A).…”

“…The mammalian TMEM16 family consists of ten members. TMEM16A and TMEM16B are Ca 2+ -activated Cl - channels (CaCCs), which participate in fluid secretion, smooth muscle contraction, gut motility, nociception, motor learning, anxiety and cancer (Hartzell, Putzier and Arreola, 2005; Caputo et al ., 2008; Yang et al ., 2008; Schroeder et al ., 2008; Berg, Yang and Jan, 2012; Cho et al ., 2012; Huang et al ., 2012; Pedemonte and Galietta, 2014; Oh and Jung, 2016; Whitlock and Hartzell, 2017; Zhang et al ., 2017; Crottès and Jan, 2019; Li et al ., 2019). Majority of the other TMEM16 members are likely not CaCCs (Suzuki et al ., 2010; Yang et al ., 2012; Huang et al ., 2013; Suzuki, Imanishi and Nagata, 2014; Whitlock et al ., 2018; Bushell, Ashley C.W.…”

Anoctamin 2-chloride channels reduce simple spike activity and mediate inhibition at elevated calcium concentration in cerebellar Purkinje cells

“…One of the main underlying questions of the controversy regarding the role of ANO2 in the olivo-cerebellar system is the exact location of expression of ANO2. As many other ion channels in the brain, ANO2 channels are expressed at low density and, therefore, sensitive methods are needed for their detection [ 3 , 6 ]. Initial evidence for the expression of ANO2 in Purkinje cells has previously been provided with immunohistochemical studies [ 10 , 11 ].…”

“…No mCherry fluorescence was detected in Purkinje cells of this mouse model [ 9 ]. Such a discrepancy also occurred when the expression of Ano2 in somatostatin-positive GABAergic neurons of the central lateral amygdala was described [ 6 ]. This study also used an in situ hybridization approach to detect an expression of Ano2 , although the mCherry-expressing Ano2 -knockout mouse line was used for the electrophysiological recordings [ 6 ].…”

“…The calcium-activated chloride channel Anoctamin 2 (ANO2) was found to decrease excitability in neurons of the hippocampus [ 3 ], thalamus [ 4 ], lateral septum [ 5 ], and central lateral amygdala [ 6 ], whereas excitability is increased in olfactory receptor neurons [ 7 , 8 ] and the olivo-cerebellar system [ 9 , 10 ]. The enhancing effects of ANO2 in the olivo-cerebellar system has been associated with impairments in motor coordination and learning tasks observed in ANO2-deficient mice ( Ano2 -/- ) [ 9 , 11 ].…”