A systematic review and meta-analysis of the preclinical and clinical results of low-field magnetic stimulation in cognitive disorders

Cognitive disorders such as major depressive disorder and bipolar disorder severely compromise brain function and neuronal activity. Treatments to restore cognitive abilities can have severe side effects due to their intense and excitatory nature, in addition to the fact that they are expensive and invasive. Low-field magnetic stimulation (LFMS) is a novel non-invasive proposed treatment for cognitive disorders. It repairs issues in the brain by altering deep cortical areas with treatments of low-intensity magnetic stimulation. This paper aims to summarize the current literature on the effects and results of LFMS in cognitive disorders. We developed a search strategy to identify relevant studies utilizing LFMS and systematically searched eight scientific databases. Our review suggests that LFMS could be a viable and effective treatment for multiple cognitive disorders, especially major depressive disorder. Additionally, longer, more frequent, and more personalized LFMS treatments tend to be more efficacious.

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.

Wistar-Kyoto rats and chronically stressed Wistar rats present similar depression- and anxiety-like behaviors but different corticosterone and endocannabinoid system modulation

The interplay of social, psychological, and biological stresses can trigger mental health conditions such as major depressive disorder (MDD), adjustment disorder, and posttraumatic stress disorder (PTSD). The endocannabinoid system (ECS), comprising endocannabinoids and cannabinoid receptors, is the critical pathway that mediates responses to stress stimuli. This study aimed to investigate the ECS's impact on responding to chronic social instability stress (SIS). Wistar (WIS) rats and an endogenously depressed rat model, Wistar-Kyoto (WKY), were used to evaluate depression- and anxiety-like behavioral responses, cognitive function, hormone levels, and ECS function. The animals in the stress group (WIS-STS and WKY-STS) were exposed to TMT (predator odor) for 10 mins (two exposures in total: one in light cycle and one in dark cycle) and daily roommate changes (30 days in total), while the control group (CTL) rats were exposed to a sham odor stimulus (distilled water) and did not undergo roommate changes. The results in the open field test suggest that WKY rats had significantly lower locomotor activity than WIS rats. In contrast, WKY rats and chronically stressed WIS rats presented similar depression- and anxiety-like behaviors and impaired cognitive function in the elevated plus maze, forced swimming test, and novel objective recognition test. However, chronic SIS did not exacerbate these behavioral changes in WKY rats. ELISA and Western blot analysis indicated that chronic SIS did not induce further upregulation of endocannabinoids and CB1R downregulation in WKY rats compared to WIS rats. In addition, the Luminex assay revealed that WKY rats showed a higher resilience on the HPA-axis modulation towards chronic SIS, distinguished by the hyperactivity of the HPA-axis modulation in WIS rats. Overall, the study revealed that the chronic SIS animal model (stressed WIS rats) and an animal model of endogenous depression (WKY rats) can generate similar behavioral changes in anxious behavior, behavioral despair, and cognitive impairment. Both animal models present hyperactivity of the ACTH modulation and ECS activity, while WKY rats are more resilient on CORT modulation towards chronic SIS.

Low-intensity pulsed ultrasound enhances neurite growth in serum-starved human neuroblastoma cells

Introduction

Low-intensity pulsed ultrasound (LIPUS) is a recognized tool for promoting nerve regeneration and repair; however, the intracellular mechanisms of LIPUS stimulation remain underexplored.

Method

The present study delves into the effects of varying LIPUS parameters, namely duty cycle, spatial average-temporal average (SATA) intensity, and ultrasound amplitude, on the therapeutic efficacy using SK-N-SH cells cultured in serum-starved conditions. Four distinct LIPUS settings were employed: (A) 50 mW/cm2, 40%, (B) 25 mW/cm2, 10%, (C) 50 mW/cm2, 20%, and (D) 25 mW/cm2, 10%.

Results

Immunochemistry analysis exhibited neurite outgrowth promotion in all LIPUS-treated groups except for Group D. Further, LIPUS treatment was found to successfully promote brain-derived neurotrophic factor (BDNF) expression and enhance the phosphorylation of extracellular signal-regulated kinase (ERK)1/2, protein kinase B (Akt), and mammalian target of rapamycin (mTOR) signaling pathways, as evidenced by western blot analysis.

Discussion

The study suggests that the parameter combination of LIPUS determines the therapeutic efficacy of LIPUS. Future investigations should aim to optimize these parameters for different cell types and settings and delve deeper into the cellular response mechanism to LIPUS treatment. Such advancements may aid in tailoring LIPUS treatment strategies to specific therapeutic needs.

A Versatile Strategy for Genetic Manipulation of Cajal-Retzius Cells in the Adult Mouse Hippocampus

Cajal-Retzius (CR) cells are transient neurons with long-lasting effects on the architecture and circuitry of the neocortex and hippocampus. Contrary to the prevailing assumption that CR cells completely disappear in rodents shortly after birth, a substantial portion of these cells persist in the hippocampus throughout adulthood. The role of these surviving CR cells in the adult hippocampus is largely unknown, partly because of the paucity of suitable tools to dissect their functions in the adult versus the embryonic brain. Here, we show that genetic crosses of the ΔNp73-Cre mouse line, widely used to target CR cells, to reporter mice induce reporter expression not only in CR cells, but also progressively in postnatal dentate gyrus granule neurons. Such a lack of specificity may confound studies of CR cell function in the adult hippocampus. To overcome this, we devise a method that not only leverages the temporary CR cell-targeting specificity of the ΔNp73-Cre mice before the first postnatal week, but also capitalizes on the simplicity and effectiveness of freehand neonatal intracerebroventricular injection of adeno-associated virus. We achieve robust Cre-mediated recombination that remains largely restricted to hippocampal CR cells from early postnatal age to adulthood. We further demonstrate the utility of this method to manipulate neuronal activity of CR cells in the adult hippocampus. This versatile and scalable strategy will facilitate experiments of CR cell-specific gene knockdown and/or overexpression, lineage tracing, and neural activity modulation in the postnatal and adult brain.

MATR3 F115C knock-in mice do not exhibit motor defects or neuropathological features of ALS

The F115C mutation in the MATR3 gene has been linked to amyotrophic lateral sclerosis (ALS). To determine the pathogenicity of the F115C mutation and the mechanism by which this mutation causes ALS, we generated mice that harbor the F115C mutation in the endogenous murine Matr3 locus. Heterozygous or homozygous MATR3 F115C knock-in mice were viable and did not exhibit motor deficits up to 2 years of age. The mutant mice showed no significant differences in the number of Purkinje cells or motor neurons compared to wild-type littermates. Neuropathological examination revealed an absence of MATR3 and TDP-43 pathology in Purkinje cells and motor neurons in the mutant mice. Together, our results suggest that the F115C mutation in MATR3 may not confer pathogenicity.

Bisphosphoglycerate Mutase Deficiency Protects against Cerebral Malaria and Severe Malaria-Induced Anemia

The replication cycle and pathogenesis of the Plasmodium malarial parasite involves rapid expansion in red blood cells (RBCs), and variants of certain RBC-specific proteins protect against malaria in humans. In RBCs, bisphosphoglycerate mutase (BPGM) acts as a key allosteric regulator of hemoglobin/oxyhemoglobin. We demonstrate here that a loss-of-function mutation in the murine Bpgm (Bpgm^L166P) gene confers protection against both Plasmodium-induced cerebral malaria and blood-stage malaria. The malaria protection seen in Bpgm^L166P mutant mice is associated with reduced blood parasitemia levels, milder clinical symptoms, and increased survival. The protective effect of Bpgm^L166P involves a dual mechanism that enhances the host's stress erythroid response to Plasmodium-driven RBC loss and simultaneously alters the intracellular milieu of the RBCs, including increased oxyhemoglobin and reduced energy metabolism, reducing Plasmodium maturation, and replication. Overall, our study highlights the importance of BPGM as a regulator of hemoglobin/oxyhemoglobin in malaria pathogenesis and suggests a new potential malaria therapeutic target.

Knockdown of genes involved in axonal transport enhances the toxicity of human neuromuscular disease-linked MATR3 mutations in Drosophila

Mutations in the nuclear matrix protein Matrin 3 (MATR3) have been identified in amyotrophic lateral sclerosis and myopathy. To investigate the mechanisms underlying MATR3 mutations in neuromuscular diseases and efficiently screen for modifiers of MATR3 toxicity, we generated transgenic MATR3 flies. Our findings indicate that expression of wild-type or mutant MATR3 in motor neurons reduces climbing ability and lifespan of flies, while their expression in indirect flight muscles (IFM) results in abnormal wing positioning and muscle degeneration. In both motor neurons and IFM, mutant MATR3 expression results in more severe phenotypes than wild-type MATR3, demonstrating that the disease-linked mutations confer pathogenicity. We conducted a targeted candidate screen for modifiers of the MATR3 abnormal wing phenotype and identified multiple enhancers involved in axonal transport. Knockdown of these genes enhanced protein levels and insolubility of mutant MATR3. These results suggest that accumulation of mutant MATR3 contributes to toxicity and implicate axonal transport dysfunction in disease pathogenesis.

RNA-Binding Proteins in Amyotrophic Lateral Sclerosis

Significant research efforts are ongoing to elucidate the complex molecular mechanisms underlying amyotrophic lateral sclerosis (ALS), which may in turn pinpoint potential therapeutic targets for treatment. The ALS research field has evolved with recent discoveries of numerous genetic mutations in ALS patients, many of which are in genes encoding RNA binding proteins (RBPs), including TDP-43, FUS, ATXN2, TAF15, EWSR1, hnRNPA1, hnRNPA2/B1, MATR3 and TIA1. Accumulating evidence from studies on these ALS-linked RBPs suggests that dysregulation of RNA metabolism, cytoplasmic mislocalization of RBPs, dysfunction in stress granule dynamics of RBPs and increased propensity of mutant RBPs to aggregate may lead to ALS pathogenesis. Here, we review current knowledge of the biological function of these RBPs and the contributions of ALS-linked mutations to disease pathogenesis.

Modulation of Malaria Phenotypes by Pyruvate Kinase (PKLR) Variants in a Thai Population

Pyruvate kinase (PKLR) is a critical erythrocyte enzyme that is required for glycolysis and production of ATP. We have shown that Pklr deficiency in mice reduces the severity (reduced parasitemia, increased survival) of blood stage malaria induced by infection with Plasmodium chabaudi AS. Likewise, studies in human erythrocytes infected ex vivo with P. falciparum show that presence of host PK-deficiency alleles reduces infection phenotypes. We have characterized the genetic diversity of the PKLR gene, including haplotype structure and presence of rare coding variants in two populations from malaria endemic areas of Thailand and Senegal. We investigated the effect of PKLR genotypes on rich longitudinal datasets including haematological and malaria-associated phenotypes. A coding and possibly damaging variant (R41Q) was identified in the Thai population with a minor allele frequency of ~4.7%. Arginine 41 (R41) is highly conserved in the pyruvate kinase family and its substitution to Glutamine (R41Q) affects protein stability. Heterozygosity for R41Q is shown to be associated with a significant reduction in the number of attacks with Plasmodium falciparum, while correlating with an increased number of Plasmodium vivax infections. These results strongly suggest that PKLR protein variants may affect the frequency, and the intensity of malaria episodes induced by different Plasmodium parasites in humans living in areas of endemic malaria.

Generation and diagnostic application of monoclonal antibodies against Seneca Valley virus

Seneca Valley virus (SVV), a member of the Picornaviridae family, was implicated in a suspicious vesicular disease discovered in pigs from Canada in 2007. Because any outbreak of vesicular disease in pigs is assumed to be foot-and-mouth disease (FMD) until confirmed otherwise, a test for diagnosing the presence of SVV would be a very useful tool. To develop the diagnostic tests for SVV infection, 5 monoclonal antibodies (mAbs) were produced from mice immunized with binary ethylenimine (BEI)-inactivated SVV. Using a dot blot assay, the reactivity of the mAbs was confirmed to be specific for SVV, not reacting with any of the other vesicular disease viruses tested. The mAbs demonstrated reactivity with SVV antigen in infected cells by an immunohistochemistry assay. An SVV-specific competitive enzyme-linked immunosorbent assay (cELISA) was developed using BEI-inactivated SVV antigen and a mAb for serodiagnosis. The cELISA results were compared to the indirect isotype (immunoglobulin [Ig]M and IgG) ELISA and the virus neutralization test. All SVV experimentally inoculated pigs exhibited a positive SVV-specific antibody response at 6 days postinoculation, and the sera remained positive until the end of the experiment on day 57 (>40% inhibition) using the cELISA. The cELISA reflected the profile of the indirect ELISA for both IgM and IgG. This panel of SVV-specific mAbs is valuable for the identification of SVV antigen and the serological detection of SVV-specific antibodies.