Characterization of bipolar disorder patient-specific induced pluripotent stem cells from a family reveals neurodevelopmental and mRNA expression abnormalities

Abstract

Bipolar disorder (BD) is a common neuropsychiatric disorder characterized by chronic recurrent episodes of depression and mania. Despite evidence for high heritability of BD, little is known about its underlying pathophysiology. To develop new tools for investigating the molecular and cellular basis of BD we applied a family-based paradigm to derive and characterize a set of 12 induced pluripotent stem cell (iPSC) lines from a quartet consisting of two BD-affected brothers and their two unaffected parents. Initially, no significant phenotypic differences were observed between iPSCs derived from the different family members. However, upon directed neural differentiation we observed that CXCR4 (CXC chemokine receptor-4) expressing central nervous system (CNS) neural progenitor cells (NPCs) from both BD patients compared to their unaffected parents exhibited multiple phenotypic differences at the level of neurogenesis and expression of genes critical for neuroplasticity, including WNT pathway components and ion channel subunits. Treatment of the CXCR4+ NPCs with a pharmacological inhibitor of glycogen synthase kinase 3 (GSK3), a known regulator of WNT signaling, was found to rescue a progenitor proliferation deficit in the BD-patient NPCs. Taken together, these studies provide new cellular tools for dissecting the pathophysiology of BD and evidence for dysregulation of key pathways involved in neurodevelopment and neuroplasticity. Future generation of additional iPSCs following a family-based paradigm for modeling complex neuropsychiatric disorders in conjunction with in-depth phenotyping holds promise for providing insights into the pathophysiological substrates of BD and is likely to inform the development of targeted therapeutics for its treatment and ideally prevention.

Probing the lithium-response pathway in hiPSCs implicates the phosphoregulatory set-point for a cytoskeletal modulator in bipolar pathogenesis

“…We observed no differences in neuronal induction efficiency and yield among LiR, LiNR, or unaffected patient-derived hiPSCs, all of which showed similar expression of neuronal markers [Tau, βIII-tubulin (Tuj1), MAP2, vGLUT, GABA] and produced neural progenitor cells (NPCs) and electrophysiologically active (17) glutamatergic (vGLUT + ) and GABAergic (GABA + ) neurons that initially expressed markers consistent with a dorsal anterior forebrain cortical phenotype (SI Appendix, Figs. S2 E-L and S3 A-J) (17)(18)(19)(20). For our in vitro studies, we elected to preserve the distinction made by clinicians between LiR and LiNR patients (5)(6)(7)(8) and to probe lithium's protein targets within LiR BPD neurons (SI Appendix, Figs.…”

“…S1) were reprogrammed to hiPSCs via nonintegrating episomalmediated (42), lentivirus-mediated (1), or retrovirus-mediated (19) gene transfer, characterized (43), and differentiated to NPCs and cortical interneurons, as per our routine and as previously described (17)(18)(19)(20). Protein isolation, 2D-DIGE and SILAC, Western blotting, and coimmunoprecipitation were performed as described previously (17,28).…”

Advancing drug discovery for neuropsychiatric disorders using patient-specific stem cell models

“…Recent findings with bipolar disorder patient iPSC-derived neural progenitor and neuronal cell models provide growing support for this notion. This includes studies by Madison et al 55 employing multiplexed mRNA expression assays and high-content imaging to phenotype iPSC-derived neural progenitors and neurons from bipolar disorder subjects relative to controls. Following a family based design, and a strategy designed to isolate a specific subpopulation of CXCR4-positive neural progenitor cells by multi-chromatic, fluorescence-activated cell sorting, the authors observed differential expression of key for neurodevelopmental genes in progenitor cells from the two bipolar disorder subjects not present in their unaffected parents 55 .…”

“…This includes studies by Madison et al 55 employing multiplexed mRNA expression assays and high-content imaging to phenotype iPSC-derived neural progenitors and neurons from bipolar disorder subjects relative to controls. Following a family based design, and a strategy designed to isolate a specific subpopulation of CXCR4-positive neural progenitor cells by multi-chromatic, fluorescence-activated cell sorting, the authors observed differential expression of key for neurodevelopmental genes in progenitor cells from the two bipolar disorder subjects not present in their unaffected parents 55 . Consistent with these expression differences, deficits in neurogenesis were also observed in the two bipolar disorder subjects compared to their unaffected parents using imaging and neural lineage-specific markers as functional read outs 55 .…”

“…Following a family based design, and a strategy designed to isolate a specific subpopulation of CXCR4-positive neural progenitor cells by multi-chromatic, fluorescence-activated cell sorting, the authors observed differential expression of key for neurodevelopmental genes in progenitor cells from the two bipolar disorder subjects not present in their unaffected parents 55 . Consistent with these expression differences, deficits in neurogenesis were also observed in the two bipolar disorder subjects compared to their unaffected parents using imaging and neural lineage-specific markers as functional read outs 55 . Interestingly, given the known pharmacological effects of the bipolar disorder medication lithium on GSK3 (Glycogen synthase kinase 3) 56 , the proliferation deficits of the bipolar disorder subjects could be rescued to the level of their unaffected parental controls by treatment with the highly selective and potent GSK3 inhibitor (CHIR-99021).…”