MATR3 pathogenic variants differentially impair its cryptic splicing repression function.

Matrin-3 (MATR3) is an RNA-binding protein implicated in neurodegenerative and neurodevelopmental diseases. However, little is known regarding the role of MATR3 in cryptic splicing within the context of functional genes and how disease-associated variants impact this function. We show that loss of MATR3 leads to cryptic exon inclusion in many transcripts. We reveal that ALS-linked S85C pathogenic variant reduces MATR3 solubility but does not impair RNA binding. In parallel, we report a novel neurodevelopmental disease-associated M548T variant, located in the RRM2 domain, which reduces protein solubility and impairs RNA binding and cryptic splicing repression functions of MATR3. Altogether, our research identifies cryptic events within functional genes and demonstrates how disease-associated variants impact MATR3 cryptic splicing repression function.

Microglia and Astrocytes in Amyotrophic Lateral Sclerosis: Disease-Associated States, Pathological Roles, and Therapeutic Potential.

Microglial and astrocytic reactivity is a prominent feature of amyotrophic lateral sclerosis (ALS). Microglia and astrocytes have been increasingly appreciated to play pivotal roles in disease pathogenesis. These cells can adopt distinct states characterized by a specific molecular profile or function depending on the different contexts of development, health, aging, and disease. Accumulating evidence from ALS rodent and cell models has demonstrated neuroprotective and neurotoxic functions from microglia and astrocytes. In this review, we focused on the recent advancements of knowledge in microglial and astrocytic states and nomenclature, the landmark discoveries demonstrating a clear contribution of microglia and astrocytes to ALS pathogenesis, and novel therapeutic candidates leveraging these cells that are currently undergoing clinical trials.

Synaptotagmin 2 is ectopically overexpressed in excitatory presynapses of a widely used CaMKΙΙα-Cre mouse line.

The CaMKΙΙα-Cre mouse lines, possibly the most used Cre lines in neuroscience, have resulted in over 800 articles to date. Here, we demonstrate that the second most widely used CaMKΙΙα-Cre line, Tg(Camk2a-cre)2Gsc (or CamiCre), shows ectopic overexpression of synaptotagmin 2, the most efficient Ca2+ sensor for fast synchronous neurotransmitter release, in excitatory presynapses of Cre+ brains. Moreover, the upregulation of immediate-early genes and genes incorporated in bacterial artificial chromosome (BAC) transgenes, such as L-proline transporter Slc6a7, was found in Cre+ hippocampus. The copy number and integration site of the transgene are suggested to have caused the aberrant gene expression in Cre+ brains. Most importantly, CamiCre+ mice showed functional phenotypes, such as hyperactivity and enhanced associative learning, suggesting that neural activities are affected. These unexpected results suggest difficulties in interpreting results from studies using the CamiCre line and raise a warning of potential pitfalls in using Cre driver lines in general.

TOB is an effector of the hippocampus-mediated acute stress response.

Stress affects behavior and involves critical dynamic changes at multiple levels ranging from molecular pathways to neural circuits and behavior. Abnormalities at any of these levels lead to decreased stress resilience and pathological behavior. However, temporal modulation of molecular pathways underlying stress response remains poorly understood. Transducer of ErbB2.1, known as TOB, is involved in different physiological functions, including cellular stress and immediate response to stimulation. In this study, we investigated the role of TOB in psychological stress machinery at molecular, neural circuit, and behavioral levels. Interestingly, TOB protein levels increased after mice were exposed to acute stress. At the neural circuit level, functional magnetic resonance imaging (fMRI) suggested that intra-hippocampal and hippocampal-prefrontal connectivity were dysregulated in Tob knockout (Tob-KO) mice. Electrophysiological recordings in hippocampal slices showed increased postsynaptic AMPAR-mediated neurotransmission, accompanied by decreased GABA neurotransmission and subsequently altered Excitatory/Inhibitory balance after Tob deletion. At the behavioral level, Tob-KO mice show abnormal, hippocampus-dependent, contextual fear conditioning and extinction, and depression-like behaviors. On the other hand, increased anxiety observed in Tob-KO mice is hippocampus-independent. At the molecular level, we observed changes in factors involved in stress response like decreased stress-induced LCN2 expression and ERK phosphorylation, as well as increased MKP-1 expression. This study introduces TOB as an important modulator in the hippocampal stress signaling machinery. In summary, we reveal a molecular pathway and neural circuit mechanism by which Tob deletion contributes to expression of pathological stress-related behavior.

Novel combination of sorafenib and biochanin-A synergistically enhances the anti-proliferative and pro-apoptotic effects on hepatocellular carcinoma cells.

Sorafenib (SOR) is the first-line treatment for hepatocellular carcinoma (HCC). However, its use is hindered by the recently expressed safety concerns. One approach for reducing SOR toxicity is to use lower doses in combination with other less toxic agents. Biochanin-A (Bio-A), a promising isoflavone, showed selective toxicity to liver cancer cells. We postulated that combining SOR and Bio-A could be synergistically toxic towards HCC cells. We further evaluated the underlying mechanism. Cytotoxicity assay was performed to determine the IC50 of Bio-A and SOR in HepG2, SNU-449 and Huh-7 cells. Then, combination index in HepG2 was evaluated using Calcusyn showing that the concurrent treatment with lower concentrations of SOR and Bio-A synergistically inhibited cell growth. Our combination induced significant arrest in pre-G and G0/G1 cell cycle phases and decrease in cyclin D1 protein level. Concomitantly, SOR/Bio-A reduced Bcl-2/Bax ratio. Furthermore, this co-treatment significantly increased caspase-3 &-9 apoptotic markers, while decreased anti-apoptotic and proliferative markers; survivin and Ki-67, respectively. Active caspase-3 in HepG2, SNU-449 and Huh-7 confirmed our synergism hypothesis. This study introduces a novel combination, where Bio-A synergistically enhanced the anti-proliferative and apoptotic effects of SOR in HCC cells, which could serve as a potential effective regimen for treatment.

Design, synthesis and in vitro antitumor activity of novel N-substituted-4-phenyl/benzylphthalazin-1-ones.

A novel series of N-substituted-4-phenylphthalazin-1-ones 14a-g bearing different anilines at the N-2 of phthalazin-1-one scaffold via acetyl-flexible linker was designed and synthesized for the development of potential anticancer agents. Compounds 19a-g were synthesized by insertion of methylene (CH2) bridge at C4-position of 14a-g to provide a flexibility for the phenyl group. The newly synthesized compounds 14a-g and 19a-g were evaluated for their anti-proliferative activity against three human tumor cell lines HepG2 hepatocellular carcinoma, HT-29 colon cancer and MCF-7 breast cancer. In particular, HepG2 and HT-29 cancer cell lines were more susceptible to the synthesized derivatives. Compound 19d (IC50 = 1.2 ± 0.09 µM) was found to be the most potent derivative against HepG2 as it was 2.9 times more active than doxorubicin (IC50 = 3.45 ± 0.54) and sorafenib (IC50 = 3.5 ± 1.04 µM). Compounds 14e, 14g, 19d and 19g with IC50 = (3.29 ± 0.45), (3.50 ± 0.846), (1.20 ± 0.09) and (3.52 ± 0.70) µM, respectively, were found to be active candidates against HepG2 cancer cells. Compounds 14e, 14g, 19d and 19g were able to induce apoptosis in HepG2, this was assured by; the significant increase in the percentage of annexin V-FITC-positive apoptotic cells (UR + LR), the down-regulation of the anti-apoptotic protein Bcl-2 and the up-regulation of the pro-apoptotic protein Bax, in addition to boosting caspase-3 levels. Moreover, cytotoxicity evaluation of the newly synthesized compounds in HT-29 revealed that compounds 14e, 14f, 19e and 19f (IC50 = 3.05 ± 0.78, 4.02 ± 1.18, 3.68 ± 0.79 and 2.98 ± 0.47 µM, respectively) were more potent than doxorubicin (IC50 = 7.70 ± 1.78 µM).