Impaired differentiation of human induced neural stem cells by TOR1A overexpression

DYT-TOR1A dystonia: an update on pathogenesis and treatment

DYT-TOR1A dystonia is a neurological disorder characterized by involuntary muscle contractions and abnormal movements. It is a severe genetic form of dystonia caused by mutations in the TOR1A gene. TorsinA is a member of the AAA + family of adenosine triphosphatases (ATPases) involved in a variety of cellular functions, including protein folding, lipid metabolism, cytoskeletal organization, and nucleocytoskeletal coupling. Almost all patients with TOR1A-related dystonia harbor the same mutation, an in-frame GAG deletion (ΔGAG) in the last of its 5 exons. This recurrent variant results in the deletion of one of two tandem glutamic acid residues (i.e., E302/303) in a protein named torsinA [torsinA(△E)]. Although the mutation is hereditary, not all carriers will develop DYT-TOR1A dystonia, indicating the involvement of other factors in the disease process. The current understanding of the pathophysiology of DYT-TOR1A dystonia involves multiple factors, including abnormal protein folding, signaling between neurons and glial cells, and dysfunction of the protein quality control system. As there are currently no curative treatments for DYT-TOR1A dystonia, progress in research provides insight into its pathogenesis, leading to potential therapeutic and preventative strategies. This review summarizes the latest research advances in the pathogenesis, diagnosis, and treatment of DYT-TOR1A dystonia.

BAG1, MGMT, FOXO1, and DNAJA1 as potential drug targets for radiosensitizing cancer cell lines

BACKGROUND AND PURPOSE

Activation of some signaling pathways can promote cell survival and have a negative impact on tumor response to radiotherapy. Here, the role of differences in expression levels of genes related to the poly(ADP-ribose) polymerase-1 (PARP-1), heat shock protein 90 (Hsp90), B-cell lymphoma 2 (Bcl-2), and phosphoinositide 3-kinase (PI3K) pathways in the survival or death of cells following X-ray exposure was investigated.

METHODS

Eight human cell cultures (MCF-7 and MDA-MB-231: breast cancers; MCF-12A: apparently normal breast; A549: lung cancer; L132: normal lung; G28, G44 and G112: glial cancers) were irradiated with X-rays. The colony-forming and real-time PCR based on a custom human pathway RT² Profiler PCR Array assays were used to evaluate cell survival and gene expression, respectively.

RESULTS

The surviving fractions at 2 Gy for the cell lines, in order of increasing radioresistance, were found to be as follows: MCF-7 (0.200 ± 0.011), G44 (0.277 ± 0.065), L132 (0.367 ± 0.023), MDA-MB-231 (0.391 ± 0.057), G112 (0.397 ± 0.113), A549 (0.490 ± 0.048), MCF-12A (0.526 ± 0.004), and G28 (0.633 ± 0.094). The rank order of radioresistance at 6 Gy was: MCF-7 < L132 < G44 < MDA-MB-231 < A549 < G28 < G112 < MCF-12A. PCR array data analysis revealed that several genes were differentially expressed between irradiated and unirradiated cell cultures. The following genes, with fold changes: BCL2A1 (21.91), TP53 (8743.75), RAD51 (11.66), FOX1 (65.86), TCP1 (141.32), DNAJB1 (3283.64), RAD51 (51.52), and HSPE1 (12887.29) were highly overexpressed, and BAX (-127.21), FOX1 (-81.79), PDPK1 (-1241.78), BRCA1 (-8.70), MLH1 (-12143.95), BCL2 (-18.69), CCND1 (-46475.98), and GJA1 (-2832.70) were highly underexpressed in the MDA-MB-231, MCF-7, MCF-12A, A549, L132, G28, G44, and G112 cell lines, respectively. The radioresistance in the malignant A549 and G28 cells was linked to upregulation in the apoptotic, DNA repair, PI3K, and Hsp90 pathway genes BAG1, MGMT, FOXO1, and DNAJA1, respectively, and inhibition of these genes resulted in significant radiosensitization.

CONCLUSIONS

Targeting BAG1, MGMT, FOXO1, and DNAJA1 with specific inhibitors might effectively sensitize radioresistant tumors to radiotherapy.

Ventral Telencephalic Patterning Protocols for Induced Pluripotent Stem Cells

The differentiation of human induced pluripotent stem cells (hiPSCs) into specific cell types for disease modeling and restorative therapies is a key research agenda and offers the possibility to obtain patient-specific cells of interest for a wide range of diseases. Basal forebrain cholinergic neurons (BFCNs) play a particular role in the pathophysiology of Alzheimer’s dementia and isolated dystonias. In this work, various directed differentiation protocols based on monolayer neural induction were tested for their effectiveness in promoting a ventral telencephalic phenotype and generating BFCN. Ventralizing factors [i.e., purmorphamine and Sonic hedgehog (SHH)] were applied at different time points, time intervals, and concentrations. In addition, caudal identity was prevented by the use of a small molecule XAV-939 that inhibits the Wnt-pathway. After patterning, gene expression profiles were analyzed by quantitative PCR (qPCR). Rostro-ventral patterning is most effective when initiated simultaneously with neural induction. The most promising combination of patterning factors was 0.5 μM of purmorphamine and 1 μM of XAV-939, which induces the highest expression of transcription factors specific for the medial ganglionic eminence, the source of GABAergic inter- and cholinergic neurons in the telencephalon. Upon maturation of cells, the immune phenotype, as well as electrophysiological properties were investigated showing the presence of marker proteins specific for BFCN (choline acetyltransferase, ISL1, p75, and NKX2.1) and GABAergic neurons. Moreover, a considerable fraction of measured cells displayed mature electrophysiological properties. Synaptic boutons containing the vesicular acetylcholine transporter (VACHT) could be observed in the vicinity of the cells. This work will help to generate basal forebrain interneurons from hiPSCs, providing a promising platform for modeling neurological diseases, such as Alzheimer’s disease or Dystonia.