Functional relationship between CABIT, SAM and 14-3-3 binding domains of GAREM1 that play a role in its subcellular localization

Sticky, Adaptable, and Many-sided: SAM protein versatility in normal and pathological hematopoietic states

With decades of research seeking to generalize sterile alpha motif (SAM) biology, many outstanding questions remain regarding this multi-tool protein module. Recent data from structural and molecular/cell biology has begun to reveal new SAM modes of action in cell signaling cascades and biomolecular condensation. SAM-dependent mechanisms underlie blood-related (hematologic) diseases, including myelodysplastic syndromes and leukemias, prompting our focus on hematopoiesis for this review. With the increasing coverage of SAM-dependent interactomes, a hypothesis emerges that SAM interaction partners and binding affinities work to fine tune cell signaling cascades in developmental and disease contexts, including hematopoiesis and hematologic disease. This review discusses what is known and remains unknown about the standard mechanisms and neoplastic properties of SAM domains and what the future might hold for developing SAM-targeted therapies.

Protection of Beta Boswellic Acid against Streptozotocin-induced Alzheimer's Model by Reduction of Tau Phosphorylation Level and Enhancement of Reelin Expression

Alzheimer's disease is a growing general health concern with huge implications for individuals and society. Beta boswellic acid, a major compound of the Boswellia serrata plant, has long been used for the treatment of various inflammatory diseases. The exact mechanism of beta boswellic acid action in Alzheimer's disease pathogenesis remains unclear. In the current study, the protective effect of beta boswellic acid on streptozotocin-induced sporadic Alzheimer's disease was surveyed. Alzheimer's disease model was induced using streptozotocin followed by an assessment of the treatment effects of beta boswellic acid in the presence of streptozotocin. The prevention effect of beta boswellic acid on Alzheimer's disease induction by streptozotocin was evaluated. Behavioral activities in the treated rats were evaluated. Histological analysis was performed. Phosphorylation of tau protein at residues Ser396 and Ser404 and the expression of reelin protein were determined. Glial fibrillary acidic protein immunofluorescence staining was applied in the hippocampus regions. Our findings indicated that beta boswellic acid decreased traveled distance and escape latency in the prevention (beta boswellic acid + streptozotocin) and treatment (streptozotocin + beta boswellic acid) groups compared to control during the acquisition test. It increased "time spent" (%) in the target quadrant. Reelin level was enhanced in rats treated with beta boswellic acid. Tau hyperphosphorylation (p-tau404) and glial fibrillary acidic protein were decreased in the prevention group while the expression of reelin protein in both groups was increased. We could suggest that the anti-inflammatory property of beta boswellic acid is one of the main factors involving in the improvement of learning and memory in rats. Therefore the antineurodegenerative effect of beta boswellic acid may be due to its ability to reactivate reelin protein.

The role of 14-3-3 proteins in cell signalling pathways and virus infection

14-3-3 proteins are highly conserved in species ranging from yeast to mammals and regulate numerous signalling pathways via direct interactions with proteins carrying phosphorylated 14-3-3-binding motifs. Recent studies have shown that 14-3-3 proteins can also play a role in viral infections. This review summarizes the biological functions of 14-3-3 proteins in protein trafficking, cell-cycle control, apoptosis, autophagy and other cell signal transduction pathways, as well as the associated mechanisms. Recent findings regarding the role of 14-3-3 proteins in viral infection and innate immunity are also reviewed.

Exposure to intranasal chromium triggers dose and time-dependent behavioral and neurotoxicological defects in rats

The extensive recorded environmental and occupational dispersal of hexavalent chromium (CrVI) dust contributes to an increased interest in its toxicological consequences. A previous study of our team described a brain injury induced by acute intranasal instillation of Cr(VI) in rats, which was characterized by oxidative stress and inflammation. This proposed a high risk of brain damage among Cr(VI) exposed individuals either environmentally or occupationally especially through the nasal cavity. Accordingly, the main aim of this study was to evaluate the effects of subacute/subsubacute/subchronic exposure to intranasal potassium dichromate (inPDC) solution in three dose levels (0.125, 0.25, or 0.5 mg/kg/day for five successive days/week) for 3 different intervals/dose: two weeks, one month, and two months, on the brain of rats. The rats were sacrificed 24 h following the last inPDC dose. The locomotor activity, motor coordination, and object recognition behavior of the rats have been measured. Evaluation of oxidative stress; evidenced by lipid peroxidation and reduced glutathione, and inflammatory markers; evidenced by interleukin 1-beta in the brain tissues, as well as the brain PI3K and PKB contents were performed. Furthermore, the brain anti-glial fibrillary acidic protein (GFAP); marker of neurotoxicity was assessed immunohistochemically. Brain histopathological alterations were also studied. The findings of the current study revealed a dose- and time-dependent inPDC-induced brain toxicity in rats, as displayed by the biochemical, immunohistochemical and histopathological evaluation. Behaviorally, the major toxic effects of inPDC were observed on the locomotor and cognition functions, however, minor effects were observed on the motor coordination. The results suggest that short-term exposure to intranasal Cr(VI), in theses doses, does not trigger a major brain injury in rats; however, observation of more toxic alterations in a time-dependent manner is a threat of more sever toxicity upon longer exposure.

Behavioral analysis in mice deficient for GAREM2 (Grb2-associated regulator of Erk/MAPK subtype2) that is a subtype of highly expressing in the brain

Grb2-associated regulator of Erk/MAPK (GAREM), is an adaptor protein related to the several cell growth factor receptor-signaling. The GAREM family has two subtypes, GAREM1 and GAREM2, both encoded in the human and mouse genome. Recent genome-wide research identified GAREM2 as a candidate of neurodegenerative diseases. Here, we use knockout (KO) mice to show the role of GAREM2, that is highly expressed in the brain. According to the comprehensive behavioral battery, they exhibited less anxiety both in elevated plus maze and open field tests, mildly increased social approaching behavior in the reciprocal social interaction test, and longer latency to immobility in the tail suspension test as compared to wild-type (WT). Additionally, the extension of neurites in the primary cultured neurons was suppressed in ones derived from GAREM2 KO mice. Furthermore, we also identified Intersectin, as a binding partner of GAREM2 in this study. Intersectin is also a multi-domain adaptor protein that regulates endocytosis and cell signaling, which can potentially alter the subcellular localization of GAREM2. The important molecules, such as the neurotrophin receptor and Erk family, that are involved in the signaling pathway of the neural cell growth in the mouse brain, have been reported to participate in emotional behavior. As GAREM plays a role in the cellular growth factor receptor signaling pathway, GAREM2 may have a common role related to the transduction of Erk signaling in the higher brain functions.

GAREM1 regulates the PR interval on electrocardiograms

PR interval is the period from the onset of P wave to the start of the QRS complex on electrocardiograms. A recent genomewide association study (GWAS) suggested that GAREM1 was linked to the PR interval on electrocardiograms. This study was designed to validate this correlation using additional subjects and examined the function of Garem1 in a mouse model. We analyzed the association of rs17744182, a variant in the GAREM1 locus, with the PR interval in 5646 subjects who were recruited from 2 Korean replication sets, Yangpyeong (n = 2471) and Yonsei (n = 3175), and noted a significant genomewide association by meta-analysis (P = 2.39 × 10^-8). To confirm the function of Garem1 in mice, Garem1 siRNA was injected into mouse tail veins to reduce the expression of Garem1. Garem1 transcript levels declined by 53% in the atrium of the heart (P = 0.029), and Garem1-siRNA injected mice experienced a significant decrease in PR interval (43.27 ms vs. 44.89 ms in control, P = 0.007). We analyzed the expression pattern of Garem1 in the heart by immunohistology and observed specific expression of Garem1 in intracardiac ganglia. Garem1 was expressed in most neurons of the ganglion, including cholinergic and adrenergic cells. We have provided evidence that GAREM1 is involved in the PR interval of ECGs. These findings increase our understanding of the regulatory signals of heart rhythm through intracardiac ganglia of the autonomic nervous system and can be used to guide the development of a therapeutic target for heart conditions, such as atrial fibrillation.

GFAP expression in injured astrocytes in rats

Glial fibrillary acidic protein (GFAP) is one of the best markers for the activation of astrocytes (AS) following injury or stress in the central nervous system (CNS). The purpose of this study was to examine the expression of GFAP and 14-3-3ε in rat AS subjected to hypoxia. We established primary cultures of AS from cerebral cortex of neonatal Sprague-Dawley rats as a model of glucose deficiency and hypoxia/ischemia-reperfusion. We analyzed the activated astrocyte markers GFAP and 14-3-3ε by western blot analysis and found that both increased over time, starting at 4 h and reaching the highest level at 72 h, at the end of the experiment. GFAP and 14-3-3ε protein localization by double-labeling immunofluorescence showed elevated expression and co-localization in the cytoplasm of AS. GFAP and 14-3-3ε expression remained elevated in AS 72 h after stress conditions, which is possibly related to the excessive activation and dysfunction of the CNS in chronic injuries.