Abstract
BackgroundOur previous study demonstrated that a store-operated calcium channel (SOCC) inhibitor (YM-58483) has central analgesic effects. However, the cellular and molecular mechanisms of such effects remain to be determined. It is well-known that glial cells play important roles in central sensitization. SOC entry (SOCE) has been implicated in many cell types including cortical astrocytes. However, the role of the SOCC family in the function of astrocytes has not been determined. Here, we thoroughly investigated the expression and the functional significance of SOCCs in spinal astrocytes.MethodsPrimary cultured astrocytes were prepared from neonatal (P2–P3) CD1 mice. Expressions of mRNAs and proteins were respectively assessed by real-time PCR and Western blot analysis. SOCE was measured using a calcium imaging system. Live-cell STIM1 translocation was detected using a confocal microscope. Cytokine levels were measured by the enzyme-linked immunosorbent assay.ResultsWe found that the SOCC family is expressed in spinal astrocytes and that depletion of calcium stores from the endoplasmic reticulum by cyclopiazonic acid (CPA) resulted in a large sustained calcium entry, which was blocked by SOCC inhibitors. Using the siRNA knockdown approach, we identified STIM1 and Orai1 as primary components of SOCCs in spinal astrocytes. We also observed thapsigargin (TG)- or CPA-induced puncta formation of STIM1 and Orai1. In addition, activation of SOCCs remarkably promoted TNF-α and IL-6 production in spinal astrocytes, which were greatly attenuated by knockdown of STIM1 or Orai1. Importantly, knockdown of STIM2 and Orai1 dramatically decreased lipopolysaccharide-induced TNF-α and IL-6 production without changing cell viability.ConclusionsThis study presents the first evidence that STIM1, STIM2, and Orai1 mediate SOCE and are involved in cytokine production in spinal astrocytes. Our findings provide the basis for future assessment of SOCCs in pain and other central nervous system disorders associated with abnormal astrocyte activities.
Highlights
Our previous study demonstrated that a store-operated calcium channel (SOCC) inhibitor (YM-58483) has central analgesic effects
This study presents the first evidence that STIM1, STIM2, and Orai1 mediate SOC entry (SOCE) and are involved in cytokine production in spinal astrocytes
Our findings provide the basis for future assessment of SOCCs in pain and other central nervous system disorders associated with abnormal astrocyte activities
Summary
Our previous study demonstrated that a store-operated calcium channel (SOCC) inhibitor (YM-58483) has central analgesic effects. The cellular and molecular mechanisms of such effects remain to be determined. It is well-known that glial cells play important roles in central sensitization. Glial cells have long been viewed as static constituents of the CNS, primarily serving support functions. This view was dramatically changed when Garrison et al found that spinal cord astrocytes were activated following nerve injury in 1991 [1]. Therapeutic strategies should be directed at more specific astrocyte functions or at specific aspects of reactive astrogliosis, by targeting astrocyterelated molecular mechanisms. The molecular mechanisms that regulate specific aspects of reactive astrogliosis such as cytokine production remain elusive
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have