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Modulation of the human ρ1 GABAA receptor by inhibitory steroids

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Abstract

Rationale

Modulators of the ρ1 GABAA receptor may be useful in the treatment of visual, sleep, and cognitive disorders. Neuroactive steroids and analogues have been shown to modulate ρ1 receptor function, but the molecular mechanisms are poorly understood.

Objectives

We employed electrophysiology and voltage-clamp fluorometry to compare the actions of several neuroactive steroids and analogues on the human ρ1 GABAA receptor.

Results

Results confirmed that P294S and T298F mutations affect modulation by steroids. The P294S mutation abolished inhibition by (3α,5β)-3-hydroxypregnan-20-one (3α5βP) while the T298F mutation eliminated inhibition by 17β-estradiol. Voltage-clamp fluorometry demonstrated that steroids differing in the presence of a charged group on C3 or nature of substituent on C17 uniquely modified fluorescence changes elicited by GABA in the extracellular domain. The I307Q mutation reversed the inhibitory effect of 3α5βP but was without effect on modulation by (3α,5β)-3-hydroxypregnan-20-one sulfate or 17β-estradiol. The effect of 3α5βP on the fluorescence change generated at Y241C was dependent on whether the steroid acted as an inhibitor or a potentiator. Further, the effect was limited to uncharged 5β-reduced steroids containing an acetyl group on C17.

Conclusions

The data demonstrate that steroids and analogues differ with respect to conformational changes elicited by these drugs as well as sensitivity to the effects of mutations. Steroids and analogues could be provisionally divided into three major groups based on their actions on the ρ1 GABAA receptor: 5β-reduced uncharged steroids, sulfated and carboxylated steroids, and 17β-estradiol. Further division among 5β-reduced uncharged steroids was based on substituent at position C17.

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References

  • Akk G, Steinbach JH (2011) Structural studies of the actions of anesthetic drugs on the gamma-aminobutyric acid type A receptor. Anesthesiology 115:1338–1348

    CAS  PubMed Central  PubMed  Google Scholar 

  • Alakuijala A, Palgi M, Wegelius K, Schmidt M, Enz R, Paulin L, Saarma M, Pasternack M (2005) GABA receptor rho subunit expression in the developing rat brain. Brain Res Dev Brain Res 154:15–23

    CAS  PubMed  Google Scholar 

  • Alakuijala A, Alakuijala J, Pasternack M (2006) Evidence for a functional role of GABA receptors in the rat mature hippocampus. Eur J Neurosci 23:514–520

    Article  PubMed  Google Scholar 

  • Amin J, Weiss DS (1994) Homomeric rho 1 GABA channels: activation properties and domains. Receptors Channels 2:227–236

    CAS  PubMed  Google Scholar 

  • Asiedu MN, Mejia G, Ossipov MK, Malan TP, Kaila K, Price TJ (2012) Modulation of spinal GABAergic analgesia by inhibition of chloride extrusion capacity in mice. J Pain 13:546–554

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  • Boue-Grabot E, Taupignon A, Tramu G, Garret M (2000) Molecular and electrophysiological evidence for a GABAc receptor in thyrotropin-secreting cells. Endocrinology 141:1627–1632

    CAS  PubMed  Google Scholar 

  • Chang Y, Weiss DS (2002) Site-specific fluorescence reveals distinct structural changes with GABA receptor activation and antagonism. Nat Neurosci 5:1163–1168

    Article  CAS  PubMed  Google Scholar 

  • Chebib M, Hinton T, Schmid KL, Brinkworth D, Qian H, Matos S, Kim HL, Abdel-Halim H, Kumar RJ, Johnston GA, Hanrahan JR (2009) Novel, potent, and selective GABAC antagonists inhibit myopia development and facilitate learning and memory. J Pharmacol Exp Ther 328:448–457

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  • Didelon F, Sciancalepore M, Savic N, Mladinic M, Bradbury A, Cherubini E (2002) gamma-Aminobutyric acidA rho receptor subunits in the developing rat hippocampus. J Neurosci Res 67:739–744

    Article  CAS  PubMed  Google Scholar 

  • Han M, Zorumski CF, Covey DF (1996) Neurosteroid analogues. 4. The effect of methyl substitution at the C-5 and C-10 positions of neurosteroids on electrophysiological activity at GABAA receptors. J Med Chem 39:4218–4232

    Article  CAS  PubMed  Google Scholar 

  • Hosie AM, Wilkins ME, da Silva HM, Smart TG (2006) Endogenous neurosteroids regulate GABAA receptors through two discrete transmembrane sites. Nature 444:486–489

    Article  CAS  PubMed  Google Scholar 

  • Jin X, Covey DF, Steinbach JH (2009) Kinetic analysis of voltage-dependent potentiation and block of the glycine alpha 3 receptor by a neuroactive steroid analogue. J Physiol 587:981–997

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  • Johnston GA, Chebib M, Hanrahan JR, Mewett KN (2003) GABA(C) receptors as drug targets. Curr Drug Targets CNS Neurol Disord 2:260–268

    Article  CAS  PubMed  Google Scholar 

  • Khatri A, Sedelnikova A, Weiss DS (2009) Structural rearrangements in loop F of the GABA receptor signal ligand binding, not channel activation. Biophys J 96:45–55

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  • Kjaer M, Nielsen H (1983) The analgesic effect of the GABA-agonist THIP in patients with chronic pain of malignant origin. A phase-1-2 study. Br J Clin Pharmacol 16:477–485

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  • Li W, Jin X, Covey DF, Steinbach JH (2007) Neuroactive steroids and human recombinant rho1 GABAC receptors. J Pharmacol Exp Ther 323:236–247

    Article  CAS  PubMed  Google Scholar 

  • Li P, Khatri A, Bracamontes J, Weiss DS, Steinbach JH, Akk G (2010) Site-specific fluorescence reveals distinct structural changes induced in the human rho 1 GABA receptor by inhibitory neurosteroids. Mol Pharmacol 77:539–546

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  • Lu L, Huang Y (1998) Separate domains for desensitization of GABA rho 1 and beta 2 subunits expressed in Xenopus oocytes. J Membr Biol 164:115–124

    Article  CAS  PubMed  Google Scholar 

  • Mannuzzu LM, Moronne MM, Isacoff EY (1996) Direct physical measure of conformational rearrangement underlying potassium channel gating. Science 271:213–216

    Article  CAS  PubMed  Google Scholar 

  • McCall MA, Lukasiewicz PD, Gregg RG, Peachey NS (2002) Elimination of the rho1 subunit abolishes GABA(C) receptor expression and alters visual processing in the mouse retina. J Neurosci 22:4163–4174

    CAS  PubMed  Google Scholar 

  • Morris KD, Amin J (2004) Insight into the mechanism of action of neuroactive steroids. Mol Pharmacol 66:56–69

    Article  CAS  PubMed  Google Scholar 

  • Morris KD, Moorefield CN, Amin J (1999) Differential modulation of the gamma-aminobutyric acid type C receptor by neuroactive steroids. Mol Pharmacol 56:752–759

    CAS  PubMed  Google Scholar 

  • Muroi Y, Czajkowski C, Jackson MB (2006) Local and global ligand-induced changes in the structure of the GABA(A) receptor. Biochemistry 45:7013–7022

    Article  CAS  PubMed  Google Scholar 

  • Pan ZH, Zhang D, Zhang X, Lipton SA (1997) Agonist-induced closure of constitutively open gamma-aminobutyric acid channels with mutated M2 domains. Proc Natl Acad Sci U S A 94:6490–6495

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  • Rozzo A, Armellin M, Franzot J, Chiaruttini C, Nistri A, Tongiorgi E (2002) Expression and dendritic mRNA localization of GABAC receptor rho1 and rho2 subunits in developing rat brain and spinal cord. Eur J Neurosci 15:1747–1758

    Article  PubMed  Google Scholar 

  • Schlicker K, McCall MA, Schmidt M (2009) GABAC receptor-mediated inhibition is altered but not eliminated in the superior colliculus of GABAC rho1 knockout mice. J Neurophysiol 101:2974–2983

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  • Shimada S, Cutting G, Uhl GR (1992) gamma-Aminobutyric acid A or C receptor? gamma-Aminobutyric acid rho 1 receptor RNA induces bicuculline-, barbiturate-, and benzodiazepine-insensitive gamma-aminobutyric acid responses in Xenopus oocytes. Mol Pharmacol 41:683–687

    CAS  PubMed  Google Scholar 

  • Wahle P, Schmidt M (2009) GABA(C) receptors are expressed in GABAergic and non-GABAergic neurons of the rat superior colliculus and visual cortex. Exp Brain Res 199:245–252

    Article  CAS  PubMed  Google Scholar 

  • Wang TL, Guggino WB, Cutting GR (1994) A novel gamma-aminobutyric acid receptor subunit (rho 2) cloned from human retina forms bicuculline-insensitive homooligomeric receptors in Xenopus oocytes. J Neurosci 14:6524–6531

    CAS  PubMed  Google Scholar 

  • Wegelius K, Pasternack M, Hiltunen JO, Rivera C, Kaila K, Saarma M, Reeben M (1998) Distribution of GABA receptor rho subunit transcripts in the rat brain. Eur J Neurosci 10:350–357

    Article  CAS  PubMed  Google Scholar 

  • Wotring VE, Chang Y, Weiss DS (1999) Permeability and single channel conductance of human homomeric rho1 GABAC receptors. J Physiol 521(Pt 2):327–336

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  • Yang L, Omori K, Otani H, Suzukawa J, Inagaki C (2003) GABAC receptor agonist suppressed ammonia-induced apoptosis in cultured rat hippocampal neurons by restoring phosphorylated BAD level. J Neurochem 87:791–800

    Article  CAS  PubMed  Google Scholar 

Download references

Acknowledgments

This work was supported by the National Institutes of Health Grant GM47969. We thank Drs. Chuck Zorumski and Steve Mennerick for the Xenopus laevis oocytes and Dr. Joe Henry Steinbach for the many stimulating discussions and comments on the manuscript.

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Authors and Affiliations

  1. Department of Anesthesiology, Washington University School of Medicine, Campus Box 8054, 660 S. Euclid Ave, St. Louis, MO, 63110, USA

    Megan M. Eaton, You Bin Lim & Gustav Akk

  2. Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA

    Douglas F. Covey

  3. Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, 63110, USA

    Douglas F. Covey & Gustav Akk

Authors
  1. Megan M. Eaton
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  2. You Bin Lim
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  3. Douglas F. Covey
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  4. Gustav Akk
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Correspondence to Gustav Akk.

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Eaton, M.M., Lim, Y.B., Covey, D.F. et al. Modulation of the human ρ1 GABAA receptor by inhibitory steroids. Psychopharmacology 231, 3467–3478 (2014). https://doi.org/10.1007/s00213-013-3379-z

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  • DOI: https://doi.org/10.1007/s00213-013-3379-z

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