Carnosic Acid Mitigates Depression-Like Behavior in Ovariectomized Mice via Activation of Nrf2/HO-1 Pathway

Inhibition of HMOX1 by MAFG potentiates the development of depression‑like behavior in mice associated with astrocyte-mediated neuroinflammation

MAF bZIP transcription factor G (MAFG)-driven astrocytes have been reported to promote inflammation in the CNS. However, its function in depression, the primary cause of disability worldwide, has not been well characterized. This study investigated the possible perturbation of heme oxygenase 1 (HMOX1, also known as HO1) by the transcription factor MAFG as an underlying mechanism of the development of depression. The GSE98793 dataset was included for gene expression analysis of whole blood from donors with major depressive disorder and controls, and the target of MAFG was predicted by multiple database mining. Mouse and cellular models of depression were established by chronic unpredictable mild stress (CUMS) and lipopolysaccharide (LPS) treatment of astrocytes, which were treated with MAFG and HMOX1 knockdown plasmids. MAFG was highly expressed in the hippocampal tissues of CUMS-challenged mice and LPS-induced astrocytes. MAFG knockdown alleviated depression-like behaviors in mice. MAFG bound to the HMOX1 promoter and repressed its transcription. Knockdown of HMOX1 exacerbated neuroinflammation in astrocytes and accelerated depression-like behavior in mice. In conclusion, MAFG knockdown attenuated CUMS-stimulated depression-like behaviors in mice by astrocyte-mediated neuroinflammation via restoration of HMOX1.

Rosemary (Rosmarinus officinalis L.) polyphenols and inflammatory bowel diseases: Major phytochemicals, functional properties, and health effects

Major polyphenols in Rosmarinus officinalis L. primarily consist of phenolic acids, phenolic diterpenes, and flavonoids, all of which have pharmacological properties including anti-inflammatory and antibacterial characteristics. Numerous in vitro and animal studies have found that rosemary polyphenols have the potential to decrease the severity of intestinal inflammation. The beneficial effects of rosemary polyphenols were associated with anti-inflammatory properties, including improved gut barrier (increased mucus secretion and tight junction), increased antioxidant enzymes, inhibiting inflammatory pathways and cytokines (downregulation of NF-κB, NLRP3 inflammasomes, STAT3 and activation of Nrf2), and modulating gut microbiota community (increased core probiotics and SCFA-producing bacteria, and decreased potential pathogens) and metabolism (changes in SCFA and bile acid metabolites). This paper provides a better understanding of the anti-inflammatory properties of rosemary polyphenols and suggests that rosemary polyphenols might be employed as strong anti-inflammatory agents to prevent intestinal inflammation and lower the risk of inflammatory bowel disease and related diseases.

Linking alterations in estrogen receptor expression to memory deficits and depressive behavior in an ovariectomy mouse model

The high risk of neurological disorders in postmenopausal women is an emerging medical issue. Based on the hypothesis of altered estrogen receptors (ERα and β) after the decline of estrogen production, we investigated the changes in ERs expressions across brain regions and depressive/amnesic behaviors. C57BL/6J female mice were ovariectomized (OVX) to establish a menopausal condition. Along with behavior tests (anxiety, depression, and memory), the expression of ERs, microglial activity, and neuronal activity was measured in six brain regions (hippocampus, prefrontal cortex, striatum, raphe nucleus, amygdala, and hypothalamus) from 4 to 12 weeks after OVX. Mice exhibited anxiety- and depressive-like behaviors, as well as memory impairment. These behavioral alterations have been linked to a suppression in the expression of ERβ. The decreased ERβ expression coincided with microglial-derived neuroinflammation, as indicated by notable activations of Ionized calcium-binding adapter molecule 1 and Interleukin-1beta. Additionally, the activity of brain-derived neurotrophic factor (BDNF), particularly in the hippocampus, decreased in a time-dependent manner from 4 to 12 weeks post-OVX. Our study provides evidence shedding light on the susceptibility to memory impairment and depression in women after menopause. This susceptibility is associated with the suppression of ERβ and alteration of ERα in six brain regions.

Resveratrol Improves Cognitive Function in Post-stroke Depression Rats by Repressing Inflammatory Reactions and Oxidative Stress via the Nrf2/HO-1 Pathway

Post-stroke depression (PSD) is a prevalent mental health issue, and resveratrol (RES) has been implicated in its management. This study aimed to elucidate the impact of RES on PSD. A PSD rat model was established through middle cerebral artery occlusion and chronic unpredictable mild stress. Rats received RES via gavage, and depressive behaviors were evaluated through various measures. Cerebral infarction areas and brain tissue pathology were assessed using TTC and H&E staining. Levels of inflammatory factors (TNF-α/IL-1β/IL-6/IL-10), neurotransmitters (ACH/DA/5-HT/BDNF), and oxidative stress-related indicators (SOD/GSH-Px/MDA), along with the total Nrf2/C-Nrf2/N-Nrf2/HO-1 proteins, were analyzed. The role of the Nrf2/HO-1 pathway was investigated by co-treating rats with RES and either an Nrf2 pathway specific inhibitor (ML385) or activator (dimethyl fumarate). PSD rats exhibited depressive behaviors, disrupted neurotransmitter levels, and oxidative stress markers. RES treatment effectively alleviated these symptoms and activated the Nrf2/HO-1 pathway in PSD rat brain tissues. Co-administration of ML385 attenuated the beneficial effects of RES in PSD rats. Altogether, RES mitigates depressive behaviors, improves cognitive dysfunction, and reduces oxidative stress and inflammatory response in PSD rats. These effects are mediated through the activation of the Nrf2/HO-1 pathway, suggesting RES as a potential therapeutic agent for PSD-related cognitive impairment.

Menopause-Associated Depression: Impact of Oxidative Stress and Neuroinflammation on the Central Nervous System-A Review

Perimenopausal depression, occurring shortly before or after menopause, is characterized by symptoms such as emotional depression, anxiety, and stress, often accompanied by endocrine dysfunction, particularly hypogonadism and senescence. Current treatments for perimenopausal depression primarily provide symptomatic relief but often come with undesirable side effects. The development of agents targeting the specific pathologies of perimenopausal depression has been relatively slow. The erratic fluctuations in estrogen and progesterone levels during the perimenopausal stage expose women to the risk of developing perimenopausal-associated depression. These hormonal changes trigger the production of proinflammatory mediators and induce oxidative stress, leading to progressive neuronal damage. This review serves as a comprehensive overview of the underlying mechanisms contributing to perimenopausal depression. It aims to shed light on the complex relationship between perimenopausal hormones, neurotransmitters, brain-derived neurotrophic factors, chronic inflammation, oxidative stress, and perimenopausal depression. By summarizing the intricate interplay between hormonal fluctuations, neurotransmitter activity, brain-derived neurotrophic factors, chronic inflammation, oxidative stress, and perimenopausal depression, this review aims to stimulate further research in this field. The hope is that an increased understanding of these mechanisms will pave the way for the development of more effective therapeutic targets, ultimately reducing the risk of depression during the menopausal stage for the betterment of psychological wellbeing.

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

D-Pinitol attenuates postmenopausal symptoms in ovariectomized mice

AIMS

Menopause is a natural process in women that can lead to post-menopausal syndrome with symptoms such as hot flushes, weight gain, anxiety, cognitive decline, and depression. Hormonal replacement therapy is commonly prescribed. However, it has serious adverse effects. Herbal medicinal products and isoflavones are used as alternatives. D-Pinitol found in Pinaceae and Fabaceae families has anti-inflammatory and antioxidant effects. However, it has not received as much attention as isoflavones. In this study, we investigated whether D-pinitol could alleviate post-menopausal symptoms using an ovariectomized (OVX) mouse model.

MAIN METHODS

Female ICR mice were divided into six groups: sham (vehicle), OVX (vehicle), OVX + D-pinitol (10, 30, 100 mg/kg, p.o.), and OVX + estradiol (0.5 mg/kg, s.c.). Treatment with vehicle, D-pinitol, and estradiol began at seven weeks post ovariectomy. We employed several behavioral tests, hot-flush test, and Western blot analysis.

KEY FINDINGS

We found that D-pinitol treatment (30, 100 mg/kg, p.o.) reversed cognitive dysfunction in OVX mice (novel object recognition and Y-maze test). Additionally, D-pinitol alleviated anxiety-like behaviors (elevated plus-maze) and reversed depressive-like behaviors (splash test, tail suspension test). It also normalized increased basal tail skin temperature in OVX mice. Moreover, D-pinitol administration reversed decreased expression of ERβ and synaptophysin and phosphorylation of ERK and PI3K-Akt-GSK-3β induced by OVX in the hippocampus and prefrontal cortex.

SIGNIFICANCE

These findings indicate that D-pinitol might be a promising candidate for treating post-menopausal symptoms by increasing ERβ and synaptophysin expression levels and activation of ERK or PI3K-Akt-GSK-3β signaling pathway, at least in part.

High-intensity interval training improves long-term memory and increases hippocampal antioxidant activity and BDNF levels in ovariectomized Wistar rats

Menopause is the period in which women cease to produce the hormone estrogen, which can trigger physiological, cognitive, and behavioral changes. In this context, alternatives are needed that can reduce the effects provided by menopause, specifically in terms of cognitive and behavioral aspects. High-intensity interval training (HIIT) is an exercise protocol that has shown the potential to improve cognition by promoting an increase in antioxidant defenses and BDNF levels. Therefore, the aim of this study was to evaluate the effects of HIIT on behavior and hippocampal neurochemistry in ovariectomized adult rats. Four groups of rats were divided into: females without ovariectomy surgery and sedentary (SHAM-SED); females with ovariectomy surgery and sedentary (OVX-SED); females without ovariectomy surgery and trained (SHAM-HIIT); females with ovariectomy surgery and trained (OVX-HIIT). After the surgical procedure and the HIIT protocol, the animals underwent anxiety (elevated plus maze and open field) and memory (novel object recognition) tests. Corticosterone was measured in blood and BDNF levels and redox status were evaluated in the hippocampus. The OVX-SED group showed low BDNF levels and antioxidant enzymes, which may be linked to the observed memory impairments. The HIIT protocol (SHAM-HIIT and OVX-HIIT groups) increased the BDNF levels and antioxidant enzymes in the hippocampus, improving the animals' memory. However, HIIT also led to increased plasma corticosterone and anxiety-like behaviors. The ovariectomy procedure induced memory impairment probably due to reductions in hippocampal BDNF levels and redox imbalance. The HIIT protocol demonstrates promising results as an alternative to improve memory in ovariectomized rats.

The Nrf2 Pathway in Depressive Disorders: A Systematic Review of Animal and Human Studies

There is increasing interest in the involvement of antioxidative systems in protecting from depression. Among these, Nrf2 occupies a central place. We aimed to review the role of Nrf2 in depression. For this reason, we conducted a PubMed search using as search strategy (psychiatr*[ti] OR schizo*[ti] OR psychot*[ti] OR psychos*[ti] OR depress*[ti] OR MDD[ti] OR BD[ti] OR bipolar[ti] OR Anxiety[ti] OR antidepress*[ti] OR panic[ti] OR obsess*[ti] OR compulsio*[ti] OR “mood disord*”[ti] OR phobi*[ti] OR agoraphob*[ti] OR anorex*[ti] OR anorect*[ti] OR bulimi*[ti] OR “eating disorder*”[ti] OR neurodevelopm*[ti] OR retardation[ti] OR autism[ti] OR autistic[ti] OR ASM[ti] OR adhd[ti] OR “attention-deficit”[ti]) AND nrf2, which on the 9th of March produced 208 results of which 89 were eligible for our purposes. Eligible articles were studies reporting data of Nrf2 manipulations or content by any treatment in human patients or animals with any animal model of depression. Most studies were on mice only (N = 58), 20 on rats only, and three on both rats and mice. There were two studies on cell lines (in vitro) and one each on nematodes and fish. Only four studies were conducted in humans, one of which was post mortem. Most studies were conducted on male animals; however, human studies were carried out on both men and women. The results indicate that Nrf2 is lower in depression and that antidepressant methods (drugs or other methods) increase it. Antioxidant systems and plasticity-promoting molecules, such as those in the Nrf2–HO-1, BDNF–TrkB, and cyclic AMP–CREB pathways, could protect from depression, while glycogen synthase kinase-3β and nuclear factor κB oppose these actions, thus increasing depressive-like behaviours. Since Nrf2 is also endowed with tumorigenic and atherogenic potential, the balance between benefits and harms must be taken into account in designing novel drugs aiming at increasing the intracellular content of Nrf2.

Neuroprotective Effects of Carnosic Acid: Insight into Its Mechanisms of Action

Carnosic acid is a diterpenoid abundantly present in plants belonging to the genus Rosmarinus and Salvia of the family Lamiaceae, accounting for their application in traditional medicine. The diverse biological properties of carnosic acid that include antioxidant, anti-inflammatory, and anticarcinogenic activities have instigated studies on its mechanistic role, providing further insights into its potential as a therapeutic agent. Accumulating evidence has established the relevance of carnosic acid as a neuroprotective agent exhibiting therapeutic efficacy in combatting neuronal-injury-induced disorders. The physiological importance of carnosic acid in the mitigation of neurodegenerative disorders is just beginning to be understood. This review summarizes the current data on the mode of action through which carnosic acid exerts its neuroprotective role that may serve to strategize novel therapeutic approaches for these debilitating neurodegenerative disorders.