RESUMO
Acid-sensing ion channels (ASICs) have emerged as important, albeit challenging therapeutic targets for pain, stroke, etc. One approach to developing therapeutic agents could involve the generation of functional antibodies against these channels. To select such antibodies, we used channels assembled in nanodiscs, such that the target ASIC1a has a configuration as close as possible to its natural state in the plasma membrane. This methodology allowed selection of functional antibodies that inhibit acid-induced opening of the channel in a dose-dependent way. In addition to regulation of pH, these antibodies block the transport of cations, including calcium, thereby preventing acid-induced cell death in vitro and in vivo. As proof of concept for the use of these antibodies to modulate ion channels in vivo, we showed that they potently protect brain cells from death after an ischemic stroke. Thus, the methodology described here should be general, thereby allowing selection of antibodies to other important ASICs, such as those involved in pain, neurodegeneration, and other conditions.
Assuntos
Bloqueadores do Canal Iônico Sensível a Ácido/farmacologia , Canais Iônicos Sensíveis a Ácido/imunologia , Apoptose/efeitos dos fármacos , Infarto Encefálico/tratamento farmacológico , Anticorpos de Cadeia Única/farmacologia , Bloqueadores do Canal Iônico Sensível a Ácido/química , Bloqueadores do Canal Iônico Sensível a Ácido/uso terapêutico , Animais , Encéfalo/irrigação sanguínea , Encéfalo/citologia , Encéfalo/efeitos dos fármacos , Infarto Encefálico/etiologia , Células CHO , Artérias Cerebrais , Cricetulus , Modelos Animais de Doenças , Humanos , Concentração de Íons de Hidrogênio , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Terapia de Alvo Molecular/métodos , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Anticorpos de Cadeia Única/química , Anticorpos de Cadeia Única/uso terapêuticoRESUMO
Acid-sensing ion channels (ASIC) are voltage-independent cationic channels that open in response to decrease in extracellular pH. Amongst different subtypes, ASIC3 has received much attention in joint inflammatory conditions including rheumatoid arthritis. There have been a number of studies showing that there is an increase in expression of ASIC3 on nerve afferents supplying joints in response to inflammatory stimulus. Accordingly, a number of selective as well as nonselective ASIC3 inhibitors have shown potential in attenuating pain and inflammation in animal models of rheumatoid arthritis. On the other hand, there have been studies showing that ASIC3 may exert protective effects in joint inflammation. ASIC-/- animals, without ASIC3 genes, exhibit more joint inflammation and destruction in comparison to ASIC+/+ animals. The present review discusses the dual nature of ASIC3 in joint inflammation with possible mechanisms.
