👤 Abdallah Abu Taha

Huntington’s disease (HD) pathogenesis involves diverse cellular mechanisms, yet the contributions of pyroptosis and ferroptosis remain elusive. Roflumilast, a phosphodiesterase-4 (PDE-4) inhibitor, has shown neuroprotective effects, but its precise mechanisms are yet to be elucidated. We evaluated the potential neuroprotective and therapeutic effects of roflumilast in 3-nitropropionic acid (3-NP)-induced HD-like neurodegeneration, focusing on pyroptotic and ferroptotic cell death signaling. Adult male Wistar rats were assigned to five groups: normal control (saline + 0.5% carboxymethyl cellulose), roflumilast-control (1 mg/kg/day, p.o. for 21 days), 3-NP (20 mg/kg/day, i.p. for seven days), roflumilast-prophylactic (1 mg/kg/day, p.o. for 21 days prior to 3-NP), and roflumilast-treatment (1 mg/kg/day, p.o. for 21 days post-3-NP). Behavioral outcomes of the open-field, rotarod, and grip strength tests were assessed. Striatal PDE-4, total and p-CREB, BDNF, interleukin-1β, and markers of pyroptosis (NLRP3, caspase-1, and gasdermin D) and ferroptosis (iron, GPx4, GSH, and malondialdehyde) were measured alongside histopathological alterations and GFAP and Iba-1 immunohistochemical staining. Bioinformatics was used to visualize the target genes’ protein-protein interaction network. Behavioral assessments revealed impaired locomotion, motor coordination, and muscle strength in the 3-NP-injected rats. Biochemical analysis showed increased striatal PDE-4 expression and decreased p-CREB/BDNF axis alongside NLRP3 inflammasome/caspase-1/gasdermin D activation and elevated interleukin-1β. In parallel, ferroptosis was evidenced by increased striatal iron and malondialdehyde levels, along with reduced GPx4 and GSH. Histopathological examination revealed pronounced striatal neurodegeneration, accompanied by enhanced GFAP and Iba-1 immunostaining, indicating astrogliosis and microglial activation. Roflumilast, administered prophylactically or therapeutically, significantly improved functional and behavioral abnormalities while ameliorating biochemical, histopathological, and immunohistochemical derangements induced by 3-NP. The therapeutic regimen exhibited superior efficacy relative to prophylaxis. Conclusively, roflumilast exerts therapeutic and neuroprotective effects in HD-like neurodegeneration by mitigating pyroptosis and ferroptosis, attenuating astrogliosis, microglial activation, and neuroinflammation, and restoring synaptic plasticity. A graphical abstract illustrating the proposed mechanistic pathway underlying the neuroprotection of the PDE-4 inhibitor roflumilast through reducing striatal pyroptosis, ferroptosis, microglial and astrocyte activation, and neuroinflammation, while restoring synaptic plasticity in experimental Huntington’s disease-like neurodegeneration induced by 3-NP. [Image: see text] Show less

Although chemotherapy remains a life-saving intervention for numerous cancer patients, it is often accompanied by depressive symptoms and cognitive impairments, "chemobrain." Noteworthy, multiple studies emphasize the role of glycogen synthase kinase 3β (GSK-3β) in depression and chemobrain; nevertheless, no available data relate GSK-3β inhibitors to chemobrain. Herein, this study aims to investigate the effect of the GSK-3β inhibitor, lithium, on behavioral and neurobiological abnormalities in a doxorubicin (DOX)-induced rat model of chemobrain. The chemobrain model was established through weekly intraperitoneal injections of doxorubicin (2 mg/kg/wk) for a duration of 4 weeks, whereas lithium (100 mg/kg/d, i.p.) was administered concomitantly over the same period. Behavioral, neurochemical, and histopathological evaluations were performed after the experimental protocol. DOX-induced depressive-like behaviors and cognitive impairments, with reduction in prefrontal cortex tropomyosin receptor kinase B receptors, brain-derived neurotrophic factor protein kinase B (BDNF), and phosphorylated protein kinase B, elevating the levels of the active form of GSK-3β, which lessened phosphorylated mammalian target of rapamycin/nuclear factor-erythroid 2-related factor 2/heme oxygenase-1 and BDNF/synapsin-1 pathways, while triggering overexpression of NF-κB, proinflammatory cytokines, oxidative stress, apoptosis, tau hyperphosphorylation, and neurodegeneration. Lithium ameliorated DOX-induced behavioral, neurochemical, and histological abnormalities. To the best of our knowledge, this study presents the first evidence that lithium treatment can modulate DOX-induced depression and cognitive deficits, potentially through revamping the BDNF/tropomyosin-related kinase receptor B/protein kinase B/GSK-3β/mammalian target of rapamycin/nuclear factor-erythroid 2-related factor 2/heme oxygenase-1 signaling cascade, thereby attenuating oxidative stress, neuroinflammation, apoptosis, neurofibrillary tangles, and subsequent neurodegeneration. SIGNIFICANCE STATEMENT: To the best of our knowledge, this study is the first to detect antidepressant and procognitive effects of lithium in DOX-induced chemobrain via GSK-3β inhibition. Accordingly, lithium offers a promising therapeutic target for the management of chemotherapy-induced depression and chemobrain. Show less

One of the major consequences of diabetes mellitus that has gained attention due to its rising incidence is cognitive impairment. Recent research suggested that sodium-glucose cotransporter-2 (SGLT-2) inhibitors can mitigate memory impairment linked to Alzheimer's disease and are now being explored for their cognitive benefits. However, their mechanisms were not thoroughly studied. This research investigates the hypothesis of the neuroprotective effect of empagliflozin administration against scopolamine-heavy metal mixture (SCO + HMM)-treated Alzheimer's rat models in comparison with memantine as a reference drug and the impact of their combination. Yet, the neuroprotective effects of memantine and empagliflozin combination against cognitive impairment have not been previously explored. This study employed adult male albino rats categorized into five groups. The impact of empagliflozin, memantine, and their concomitant administration on cognitive performance was assessed in a scopolamine and heavy metal mixture-treated Alzheimer's disease model in rats. The assessment of rats' cognitive behavior, memory, and spatial learning was conducted, followed by an evaluation of hippocampal brain-derived neurotrophic factor (BDNF), beta-secretase (BACE-1), oxidative stress (OS), and inflammatory marker activity. And, a western blot analysis was conducted to detect phosphorylated 5' AMP-activated protein kinase (p-AMPK), phosphorylated mammalian target of rapamycin (p-mTOR), and heme oxygenase-1 (HO-1). Hippocampal and cerebellar histopathology were thoroughly examined, in addition to the expressions of amyloid β (Aβ). The current data demonstrate the involvement of the pAMPK/mTOR/HO-1 signaling pathway in empagliflozin neuroprotection against SCO + HMM-induced AD. In addition, it reduces AD hallmarks (Aβ and BACE1), neuro-inflammation, and oxidative stress sequelae, and enhances neurogenesis and synaptic density via BDNF. This study proposes that EMPA, especially when co-administered with other conventional anti-Alzheimer therapy, may be formulated into an innovative therapeutic strategy for the enhancement of cognitive impairments associated with neurodegenerative disorders. Show less

METTL3, an m6A methyltransferase, is integral to the regulation of messenger RNA (mRNA) biogenesis, degradation, and translation through the N6-methyladenosine (m6A) modification. Alterations in m6A homeostasis have been implicated in the development, progression, invasion, and metastasis of certain cancers. The present research aims to examine the consequences of METTL3 knockdown using short hairpin RNA (shRNA) on the proliferation and invasive capabilities of human colorectal and melanoma cancer cell lines. A specific shRNA against METTL3 mRNA was designed and inserted into an expression vector. Highly invasive colorectal cancer cell line SW480 and melanoma cell line A375 were cultured and transfected by METTL3-shRNA and scramble-control vectors and kept under culture condition for 2 weeks. The cells were harvested for analysis of gene expression by quantitative polymerase chain reaction (qPCR), invasion assay using three-dimensional (3D) spheroid assay and cell cycle and apoptosis analyses. In the METTL3-shRNA transfected cells, the expression of METTL3, VIM, SNAI1, SNAI2, ZEB1, CDH1, and TGFB1 genes were downregulated significantly compared with the scramble-control transfected cells. Expression of b-catenin, N-cadherin, vimentin, ZEB1, pro- and active MMP2, OCT4A, SOX2, and MYC proteins were also downregulated following METTL3 knockdown. Transfection by METTL3-shRNA reduced proliferation rate of the cells and increased the apoptotic rate significantly. Both migration and invasion rate of the cancer cells transfected with METTL3-shRNA were significantly decreased. These findings highlight the pro-oncogenic function of METTL3 in colorectal and melanoma cancer cells, indicating that inhibiting METTL3 could be a promising approach for tumor suppression across multiple cancer types; nonetheless, further investigation is essential to confirm these observations. Show less

CXCR4 plays an important role in colorectal cancer (CRC) development and metastasis. Some previous studies have indicated CXCR4 as a therapeutic target in cancer. CXCR4 is known as a direct target of miR-146a. The present study aimed to investigate how exogenous induction of miR-146a affects CXCR4 gene and protein expression and also proliferation, apoptosis and migration of CRC cells. Transfection of Caco-2 and SW480 cells by a synthetic miR-146a mimic led to downregulation of CXCR4 expression at both gene and protein levels. It also downregulated expression of several miR-146a targets, including GSK3B, IRAK1, TRAF6, AKT2, SMAD4, EGFR and NFKB1, mostly in SW480 cells. Overexpression of miR-146a resulted in a partial cell cycle arrest in the both cell lines, while the apoptotic rate was also decreased. In regards to epithelial-mesenchymal transition factors, VIM was downregulated in the both cell lines, but SNAI1 was upregulated in Caco-2 cells. The wound closure assay showed a reduction in cell migration in SW480 cells, but an opposite effect was detected in Caco-2 cells following transfection with miR-146a mimic. Therefore, our results are indicating that overexpression of miR-146a, despite downregulation of oncogenic CXCR4, may not lead to a universal tumor suppressive effect in all CRC cells, and this is possibly due to differences in miR-146a effects on signaling pathways in each cell type. Selection of miR-146a for tumor suppression requires enough details regarding the signaling profile of cancer cells otherwise it may produce unexpected outcome. Show less

Aberrant formation of blood vessels precedes a broad spectrum of vascular complications; however, the cellular and molecular events governing vascular malformations are not yet fully understood. Here, we investigated the role of CDC42 (cell division cycle 42) during vascular morphogenesis and its relative importance for the development of cerebrovascular malformations. To avoid secondary systemic effects often associated with embryonic gene deletion, we generated an endothelial-specific and inducible knockout approach to study postnatal vascularization of the mouse brain. Postnatal endothelial-specific deletion of Cdc42 elicits cerebrovascular malformations reminiscent of cerebral cavernous malformations (CCMs). At the cellular level, loss of CDC42 function in brain endothelial cells (ECs) impairs their sprouting, branching morphogenesis, axial polarity, and normal dispersion within the brain tissue. Disruption of CDC42 does not alter EC proliferation, but malformations occur where EC proliferation is the most pronounced during brain development-the postnatal cerebellum-indicating that a high, naturally occurring EC proliferation provides a permissive state for the appearance of these malformations. Mechanistically, CDC42 depletion in ECs elicited increased MEKK3 (mitogen-activated protein kinase kinase kinase 3)-MEK5 (mitogen-activated protein kinase kinase 5)-ERK5 (extracellular signal-regulated kinase 5) signaling and consequent detrimental overexpression of KLF (Kruppel-like factor) 2 and KLF4, recapitulating the hallmark mechanism for CCM pathogenesis. Through genetic approaches, we demonstrate that the coinactivation of Klf4 reduces the severity of vascular malformations in Cdc42 mutant mice. Moreover, we show that CDC42 interacts with CCMs and that CCM3 promotes CDC42 activity in ECs. We show that endothelial-specific deletion of Cdc42 elicits CCM-like cerebrovascular malformations and that CDC42 is engaged in the CCM signaling network to restrain the MEKK3-MEK5-ERK5-KLF2/4 pathway. Show less