Multitarget-directed cotreatment with cilostazol and aripiprazole for augmented neuroprotection against oxidative stress-induced toxicity in HT22 mouse hippocampal cells

Cilostazol counteracts mitochondrial dysfunction in hepatic encephalopathy rat model: Insights into the role of cAMP/AMPK/SIRT1/ PINK-1/parkin hub and p-CREB /BDNF/ TrkB neuroprotective trajectory

A devasting stage of chronic hepatic dysfunction is strictly correlated with neurological impairment, signifying hepatic encephalopathy (HE). HE is a multifactorial condition; therefore, hyperammonemia, oxidative stress, neuroinflammation, and mitochondrial dysfunction interplay in HE's progressive development. Cilostazol (Cilo) has shown promising neuroprotective and hepatoprotective effectiveness in different neuronal and hepatic disorders; however, its efficiency against HE hasn't yet been explored. This study aimed to investigate the protective role of Cilo against thioacetamide (TAA)-induced HE in rats targeting mitochondrial dysfunction via modulation of Adenosine monophosphate-activated protein kinase (AMPK)/Silent information regulator 1 (SIRT1) dependent pathways. Rats were allocated into three groups: the normal control group, the TAA group received (100 mg/kg, three times per week, for six weeks) to induce HE, and the Cilo group received (Cilo 100 mg/kg/day for six weeks, oral gavage) concurrently with TAA. Cilo counteracted HE indicated in the enhancement of cognitive impairment and the motor performance of rats (P < 0.0001), modulation AMPK/SIRT1signaling pathway causing reduction of NF-kB p65 (P < 0.0001) evoked inflammation along with histopathological alterations and glial fibrillary acidic protein (GFAP) immunoreactivity (P < 0.0001), restoration nuclear factor E2-related factor 2 (Nrf2) (P < 0.0001) antioxidant effects, reduction of Bax and elevation of Bcl2 immunoreactivity (P < 0.0001) in addition to boosting mitochondrial biogenesis by upregulation of PTEN-induced kinase-1 (PINK-1)/Parkin (P < 0.0001)and restoration of Brain-derived neurotrophic factor (BDNF) (P = 0.0002)/tropomyosin-related kinase B (TrkB) (P < 0.0001)/cAMP response element-binding (CREB) (P < 0.0001) neuroprotective axis. Collectively, Cilo activates the SIRT1 trajectory to abridge mitochondrial dysfunction invigorated in the HE rat model via restoration of mitochondrial hemostasis.

Memantine/Aripiprazole Combination Alleviates Cognitive Dysfunction in Valproic Acid Rat Model of Autism: Hippocampal CREB/BDNF Signaling and Glutamate Homeostasis

Significant efforts are increasingly directed towards identifying novel therapeutic targets for autism spectrum disorder (ASD) with a rising role of aberrant glutamatergic transmission in the pathogenesis of ASD-associated cellular and behavioral deficits. This study aimed at investigating the role of chronic memantine (20 mg/kg/day) and aripiprazole (3 mg/kg/day) combination therapy in the management of prenatal sodium valproate (VPA)-induced autistic-like/cognitive deficits in male Wistar rats. Pregnant female rats received a single intraperitoneal injection of VPA (600 mg/kg) to induce autistic-like behaviors in their offspring. Prenatal VPA induced autistic-like symptoms (decreased social interaction and the appearance of stereotyped behavior) with deficits in spatial learning (in Morris water maze) and cognitive flexibility (in the attentional set-shifting task) in addition to decreased hippocampal protein levels of phosphorylated cAMP response element-binding protein (p-CREB), brain-derived neurotrophic factor (BDNF), and gene expression of glutamate transporter-1 (Glt-1) with a decline in GABA/glutamate ratio (both measured by HPLC). These were accompanied by the appearance of numerous neurofibrillary tangles (NFTs) with enhanced apoptosis in hippocampal sections. Memantine/aripiprazole combination increased the protein levels of p-CREB, BDNF, and Glt-1 gene expression with restoration of GABA/glutamate balance, attenuation of VPA-induced neurodegenerative changes and autistic-like symptoms, and improvement of cognitive performance. This study draws attention to the favorable cognitive effects of memantine/aripiprazole combination in autistic subjects which could be mediated via enhancing CREB/BDNF signaling with increased expression of astrocytic Glt-1 and restoration of GABA/glutamate balance, leading to inhibition of hippocampal NFTs formation and neuronal apoptosis.

Cilostazol attenuates cardiac oxidative stress and inflammation in hypercholesterolemic rats

Atherosclerosis is a multifactorial chronic disease associated with pro-inflammatory and pro-oxidative cardiovascular states. Cilostazol, a selective phosphodiesterase 3 inhibitor (PDE3), is clinically used in the treatment of intermittent claudication and secondary prevention of cerebral infarction. The aim of this study was to evaluate the cardioprotective effects of cilostazol and the molecular mechanisms involved in hypercholesterolemic rats. Male Wistar rats were divided into four groups: control group (C) and control + cilostazol group (C+CILO), that were fed a standard chow diet, and hypercholesterolemic diet group (HCD) and HCD + cilostazol (HCD+CILO) that were fed a hypercholesterolemic diet. Cilostazol treatment started after 30 days for C+CILO and HCD+CILO groups. Animals were administered cilostazol once a day for 15 days. Subsequently, serum and left ventricles were extracted for evaluation of lipid profile, inflammatory, and oxidative biomarkers. The HCD group displayed increased serum lipid levels, inflammatory cytokines production, and cardiac NF-kB protein expression and decreased cardiac Nrf2-mediated antioxidant activity. Conversely, the cilostazol treatment improved all these cardiac deleterious effects, inhibiting NF-kB activation and subsequently decreasing inflammatory mediators, reestablishing the antioxidant properties through Nrf2-mediated pathway, including increased SOD, GPx, and catalase expression. Taken together, our results indicated that cilostazol protects hypercholesterolemia-induced cardiac damage by molecular mechanisms targeting the crosstalk between Nrf2 induction and NF-kB inhibition in the heart.

The brain heme oxygenase/biliverdin reductase system as a target in drug research and development

INTRODUCTION

The heme oxygenase/biliverdin reductase (HO/BVR) system is involved in heme metabolism. The inducible isoform of HO (HO-1) and BVR both exert cytoprotective effects by enhancing cell stress response. In this context, some xenobiotics, which target HO-1, including herbal products, behave as neuroprotectants in several experimental models of neurodegeneration. Despite this, no drug having either HO-1 or BVR as a main target is currently available.

AREAS COVERED

After a description of the brain HO/BVR system, the paper analyzes the main classes of drugs acting on the nervous system, with HO as second-level target, and their neuroprotective potential. Finally, the difficulties that exist for the development of drugs acting on HO/BVR and the possible ways to overcome these hurdles are examined.

EXPERT OPINION

Although the limited clinical evidence has restricted the translational research on the HO/BVR system, mainly because of the dual nature of its by-products, there has been growing interest in the therapeutic potential of these enzymes. Scientists should boost the translational research on the HO/BVR system which could be supported by the significant evidence provided by preclinical studies.

The effect of propofol on hypoxia- and TNF-α-mediated BDNF/TrkB pathway dysregulation in primary rat hippocampal neurons

AIMS

Hypoxia and inflammation may lead to BDNF/TrkB dysregulation and neurological disorders. Propofol is an anesthetic with neuroprotective properties. We wondered whether and how propofol affected BDNF/TrkB pathway in hippocampal neurons and astrocytes.

METHODS

Primary rat hippocampal neurons and astrocytes were cultured and exposed to propofol followed by hypoxia or TNF-α treatment. The expression of BDNF and the expression/truncation/phosphorylation of TrkB were measured. The underlying mechanisms were investigated.

RESULTS

Hypoxia and TNF-α reduced the expression of BDNF, which was reversed by pretreatment of 25 μM propofol in hippocampal neurons. Furthermore, hypoxia and TNF-α increased the phosphorylation of ERK and phosphorylation of CREB at Ser142, while reduced the phosphorylation of CREB at Ser133, which were all reversed by 25 μM propofol and 10 μM ERK inhibitor. In addition, hypoxia or TNF-α did not affect TrkB expression, truncation, or phosphorylation in hippocampal neurons and astrocytes. However, in hippocampal neurons, 50 μM propofol induced TrkB phosphorylation, which may be mediated by p35 expression and Cdk5 activation, as suggested by the data showing that blockade of p35 or Cdk5 expression mitigated propofol-induced TrkB phosphorylation.

CONCLUSIONS

Propofol modulated BDNF/TrkB pathway in hippocampal neurons via ERK/CREB and p35/Cdk5 under the condition of hypoxia or TNF-α exposure.

Hydrogen peroxide induces progranulin expression to control neurite outgrowth in HT22 cells

Progranulin (PGRN) is a multifunctional growth factor expressed in central nervous system. Although PGRN expression is regulated by various stressors, its precise role(s) and regulatory mechanism(s) remain elusive. In this study, we used HT22 cells to investigate the physiological implications of oxidative stress-induced PGRN expression and the regulation of PGRN expression by oxidative stress. We observed that p38 MAP kinase was activated upon the addition of H2O2, and a selective p38 MAP kinase inhibitor attenuated PGRN induction by H2O2. To explore the physiological role(s) of the PGRN induction, we first confirmed H2O2-dependent responses of HT22 cells and found that the length and number of neurites were increased by H2O2. Pgrn knockdown experiments suggested that these changes were mediated by H2O2-induced PGRN expression, at least in part. Overall, the results suggested that an increase in oxidative stress in HT22 cells induced PGRN expression via p38 MAP kinase pathway, thereby controlling neurite outgrowth.

Association between Blood Pressure, Blood Pressure Variability, and Post-Stroke Cognitive Impairment

After stroke, dynamic changes take place from necrotic-apoptotic continuum, inflammatory response to poststroke neurogenesis, and remodeling of the network. These changes and baseline brain pathology such as small vessel disease (SVD) and amyloid burden may be associated with the occurrence of early or late poststroke cognitive impairment (PSCI) or dementia (PSD), which affect not only stroke victims but also their families and even society. We reviewed the current concepts and understanding of the pathophysiology for PSCI/PSD and identified useful tools for the diagnosis and the prediction of PSCI in serological, CSF, and image characteristics. Then, we untangled their relationships with blood pressure (BP) and blood pressure variability (BPV), important but often overlooked risk factors for PSCI/PSD. Finally, we provided evidence for the modifying effects of BP and BPV on PSCI as well as pharmacological and non-pharmacological interventions and life style modification for PSCI/PSD prevention and treatment.

Pharmacological Treatment of Vascular Dementia: A Molecular Mechanism Perspective

Vascular dementia (VaD) is a neurodegenerative disease, with cognitive dysfunction attributable to cerebrovascular factors. At present, it is the second most frequently occurring type of dementia in older adults (after Alzheimer's disease). The underlying etiology of VaD has not been completely elucidated, which limits its management. Currently, there are no approved standard treatments for VaD. The drugs used in VaD are only suitable for symptomatic treatment and cannot prevent or reduce the occurrence and progression of VaD. This review summarizes the current status of pharmacological treatment for VaD, from the perspective of the molecular mechanisms specified in various pathogenic hypotheses, including oxidative stress, the central cholinergic system, neuroinflammation, neuronal apoptosis, and synaptic plasticity. As VaD is a chronic cerebrovascular disease with multifactorial etiology, combined therapy, targeting multiple pathophysiological factors, may be the future trend in VaD.