STIM1 deficiency is linked to Alzheimer’s disease and triggers cell death in SH-SY5Y cells by upregulation of L-type voltage-operated Ca2+ entry

Abstract

STIM1 is an endoplasmic reticulum protein with a role in Ca2+ mobilization and signaling. As a sensor of intraluminal Ca2+ levels, STIM1 modulates plasma membrane Ca2+ channels to regulate Ca2+ entry. In neuroblastoma SH-SY5Y cells and in familial Alzheimer’s disease patient skin fibroblasts, STIM1 is cleaved at the transmembrane domain by the presenilin-1-associated γ-secretase, leading to dysregulation of Ca2+ homeostasis. In this report, we investigated expression levels of STIM1 in brain tissues (medium frontal gyrus) of pathologically confirmed Alzheimer’s disease patients, and observed that STIM1 protein expression level decreased with the progression of neurodegeneration. To study the role of STIM1 in neurodegeneration, a strategy was designed to knock-out the expression of STIM1 gene in the SH-SY5Y neuroblastoma cell line by CRISPR/Cas9-mediated genome editing, as an in vitro model to examine the phenotype of STIM1-deficient neuronal cells. It was proved that, while STIM1 is not required for the differentiation of SH-SY5Y cells, it is absolutely essential for cell survival in differentiating cells. Differentiated STIM1-KO cells showed a significant decrease of mitochondrial respiratory chain complex I activity, mitochondrial inner membrane depolarization, reduced mitochondrial free Ca2+ concentration, and higher levels of senescence as compared with wild-type cells. In parallel, STIM1-KO cells showed a potentiated Ca2+ entry in response to depolarization, which was sensitive to nifedipine, pointing to L-type voltage-operated Ca2+ channels as mediators of the upregulated Ca2+ entry. The stable knocking-down of CACNA1C transcripts restored mitochondrial function, increased mitochondrial Ca2+ levels, and dropped senescence to basal levels, demonstrating the essential role of the upregulation of voltage-operated Ca2+ entry through Cav1.2 channels in STIM1-deficient SH-SY5Y cell death.Key messages STIM1 protein expression decreases with the progression of neurodegeneration in Alzheimer’s disease.STIM1 is essential for cell viability in differentiated SH-SY5Y cells.STIM1 deficiency triggers voltage-regulated Ca2+ entry-dependent cell death.Mitochondrial dysfunction and senescence are features of STIM1-deficient differentiated cells. Electronic supplementary materialThe online version of this article (10.1007/s00109-018-1677-y) contains supplementary material, which is available to authorized users.

Intracellular Calcium Dysregulation by the Alzheimer’s Disease-Linked Protein Presenilin 2

“…The decreased SOCE has been found in different cell models expressing PS1 or PS2 mutants [129,133,148,151,153,166,167], as well as in human fibroblasts from both PS1 and PS2 FAD-patients [129,153] (Figure 1). This effect of PSs on SOCE is explained, at least partially, by a significant reduction in STIM1 levels, found in mutant PS-expressing cells, human FAD fibroblasts, and in the brains of SAD patients [153,168]. Importantly, a SOCE attenuation has been reported also in mushroom spines of hippocampal neurons from FAD-PS1 M146 V knock-in mice, where STIM2 seems to be the essential SOCE component responsible for the degeneration of neuronal spines [169,170].…”

Presenilin-2 and Calcium Handling: Molecules, Organelles, Cells and Brain Networks

“…In PS double knock out (KO) MEFs and in B-lymphocytes derived from patients expressing FAD-PS mutants [ 73 ], researchers have found that the levels of the key SOCE components Stromal interaction molecule (STIM) STIM1 and STIM2 [ 68 , 69 ] are reduced. Of note, alterations in SOCE and STIM1 protein level have also been reported in sporadic AD (SAD) patients [ 74 ]. It has been proposed that SOCE is regulated by a γ-secretase-dependent mechanism, with STIM1 being a substrate of PS1-containing γ-secretase complexes [ 71 ].…”

RAC1-Dependent ORAI1 Translocation to the Leading Edge Supports Lamellipodia Formation and Directional Persistence

“…To stably transfect ORAI1-KO cells with a mammalian expression vector containing the ORAI1 cDNA, retroviral transduction was performed as described previously 59 . Briefly, Phoenix amphotropic retroviral packaging cells were transfected (6 μg DNA per 10-cm dish) with the pBABED-Hygro-ORAI1 plasmid.…”

“…Cytosolic free calcium concentration measurement. [Ca 2+ ] i was measured in fura-2-AM-loaded cells as described elsewhere 5,13,29,32,59,[61][62][63] . Excitation fluorescence wavelengths were selected with 340/26 and 387/11 nm filters (Semrock), and emission fluorescence with a 510/10 nm filter.…”