Targeting Oxidative Stress, Cytokines and Serotonin Interactions Via Indoleamine 2, 3 Dioxygenase by Coenzyme Q10: Role in Suppressing Depressive Like Behavior in Rats

Discovering the Potential Value of Coenzyme Q10 as an Adjuvant Treatment in Patients With Depression

PURPOSE/BACKGROUND

Depressive disorder or mental cold is the most common mental disorder, and depression exists all over the world and in all countries and cultures. The results of several studies have shown that using compounds with antioxidant properties has been fruitful in patients with depression. Coenzyme Q10 (CoQ10) is a fat-soluble antioxidant and exerts its antioxidant effect by directly neutralizing free radicals or reducing tocopherol and preventing the inhibition of mitochondrial activity because of oxidative stress. This study aimed to investigate the effects of oral CoQ10 in patients with depression as an adjunctive treatment.

METHODS/PROCEDURES

Sixty-nine patients with moderate and severe depression were randomly divided into 2 CoQ10 groups (36) and placebo (33). The first group of patients received CoQ10 supplements at a dose of 200 mg daily for 8 weeks along with standard interventions and treatments for depression, and the second group received standard treatments for depression along with a placebo. The change in the score of Montgomery-Åsberg Depression Rating Scale depression scale was evaluated 4 and 8 weeks after the intervention. Also, at baseline and 8 weeks later at the end of the study, serum levels of total antioxidant capacity, total thiol groups, nitric oxide, malondialdehyde, and interleukin 6 were assessed.

FINDINGS/RESULTS

The changes in the depression score at the end of the study showed that, in the group receiving the CoQ10 supplement after 8 weeks, there was a reduction in depression symptoms, which was statistically significant compared with before the start of the study Meanwhile, no significant changes were observed in the patients of the placebo group in terms of symptom reduction. Compared with baseline and the placebo condition, serum levels of nitric oxide and total thiol groups significantly decreased and increased, respectively. Also, no statistically significant changes were observed for interleukin 6, malondialdehyde, and total antioxidant capacity.

IMPLICATIONS/CONCLUSIONS

A dose of 200 mg of CoQ10 supplement daily for 8 weeks can reduce depression and fatigue, as well as improve the quality of life of patients with depression. In addition, CoQ10 can significantly improve inflammation and oxidative stress status in patients with depression.

Dietary Co-supplements attenuate the chronic unpredictable mild stress-induced depression in mice

Does it make a difference what we eat when it comes to our mental health? Food and nutrients are essential not only for human biology and physical appearance but also for mental and emotional well-being. There has been a significant increase in the favourable effects of dietary supplements in the treatment of depressive state in the latest days. Co-supplements which can be a great contribution in the management of depression from the future perspective and might help to reduce standard anti-depressant drug doses, which can be a strategic way to reduce the side effect of standard anti-depressants drugs. This study was designed to evaluate and compare the anti-depressant effects of cholecalciferol-D3 (V.D3), n-3 polyunsaturated fatty acid (PUFA), and a combination of V.D3 + n-3 PUFA with fluoxetine treatment in chronic unpredictable mild stress (CUMS) induced depression in the mice model. We established CUMS depressant mice model and treated CUMS mice with V.D3, n-3 PUFA, and a combination of V.D3 + n-3 PUFA with fluoxetine. Behavioral changes were measured by the forced swim and tail suspension test. Oxidative stress markers and anti-depressant activity were assessed through parameters such as superoxide dismutase, reduced glutathione, lipid peroxidation, and serum corticosterone levels. Additionally, we measured the levels of neurotransmitters dopamine and serotonin. CUMS induced mice displayed depressive-like behaviours. Moreover, cholecalciferol-D3, n-3 PUFA, and a combination of Cholecalciferol-D3 + n-3 PUFA with fluoxetine treatment attenuated the depressive-like behaviour in CUMS mice accompanied with suppression of oxidative stress markers by up-regulated the expression of an antioxidant signalling pathway. The results suggested that treatment of cholecalciferol-D3, n-3 PUFA, and a combination of Cholecalciferol-D3 + n-3 PUFA with fluoxetine significantly ameliorated depressive-like behaviours in CUMS induced depression in mice. To delve further into the implications of these findings, future studies could explore the specific molecular mechanisms underlying the observed effects on oxidative stress markers and the antioxidant signaling pathway. This could provide valuable insights into the potential of dietary supplements in the management of depression and help in reducing the reliance on conventional antidepressant medications, thus improving the overall quality of treatment for this prevalent mental health condition.

Di (2-ethylhexyl) phthalate alters neurobehavioral responses and oxidative status, architecture, and GFAP and BDNF signaling in juvenile rat's brain: Protective role of Coenzyme10

Di-(2-ethylhexyl) phthalate (DEHP), a phthalate plasticizer, is widely spread in the environment, presenting hazards to human health and food safety. Hence, this study examined the probable preventive role of coenzyme10 (CQ10) (10 mg/kg.b.wt) against DEHP (500 mg/kg.wt) - induced neurotoxic and neurobehavioral impacts in juvenile (34 ± 1.01g and 3 weeks old) male Sprague Dawley rats in 35-days oral dosing trial. The results indicated that CQ10 significantly protected against DEHP-induced memory impairment, anxiety, depression, spatial learning disorders, and repetitive/stereotypic-like behavior. Besides, the DEHP-induced depletion in dopamine and gamma amino butyric acid levels was significantly restored by CQ10. Moreover, CQ10 significantly protected against the exhaustion of CAT, GPx, SOD, GSH, and GSH/GSSG ratio, as well as the increase in malondialdehyde, Caspas-3, interleukin-6, and tumor necrosis factor-alpha brain content accompanying with DEHP exposure. Furthermore, CQ10 significantly protected the brain from the DEHP-induced neurodegenerative alterations. Also, the increased immunoexpression of brain-derived neurotrophic factor, not glial fibrillary acidic protein, in the cerebral, hippocampal, and cerebellar brain tissues due to DEHP exposure was alleviated with CQ10. This study's findings provide conclusive evidence that CQ10 has the potential to be used as an efficient natural protective agent against the neurobehavioral and neurotoxic consequences of DEHP.

Integrating serum metabolomics and network analysis to explore the antidepressant activity of crocin in rats with chronic unexpected mild stress-induced depression

CONTEXT

Crocin exhibits anti-depressant properties. However, its underlying mechanisms and its relationship with metabolomics remain unclear.

OBJECTIVE

This study elucidates the mechanism of action and potential targets of crocin in treating chronic unexpected mild stress (CUMS)-induced depression in rats.

MATERIALS AND METHODS

Male Sprague-Dawley (SD) rats underwent 4 weeks of CUMS to establish the depression model. The normal control (distilled water), crocin (25 mg/kg), and fluoxetine (5.4 mg/kg) groups were orally administered for 4-weeks. Behavioural tests evaluated the effects of crocin, while liquid chromatography-mass spectrometry metabolomics identified differential metabolites and their associated metabolic pathways. Subsequently, network pharmacology was utilized to predict the targets of crocin.

RESULTS

Crocin significantly increased body weight (from 319.16 ± 4.84 g to 325.67 ± 2.84 g), sucrose preference (from 0.46 ± 0.09 to 0.70 ± 0.09), vertical activity (from 2.83 ± 1.94 to 8 ± 2.36), horizontal activity (from 1 ± 0.63 to 4.5 ± 3.08) and decreased immobilization time (from 13.16 ± 2.69 to 3.97 ± 3.00). Metabolomics analysis identified 7 metabolites and 5 associated metabolic pathways. From the combined analysis of network pharmacology and metabolomics, three targets (PRMT1, CYP3A4, and GLB1) are the overlapping targets and the two most important metabolic pathways are tryptophan metabolism and glycerolipid metabolism.

DISCUSSION AND CONCLUSIONS

This study provides insights into the antidepressant therapeutic effect of crocin and its underlying mechanisms. The findings contribute to a better understanding of the metabolic mechanism involved in the anti-depressant effect of crocin, establishing a strong foundation for future research in this area.

Putative role of glial cells in treatment resistance depression: An updated critical literation review and evaluation of single-nuclei transcriptomics data

AIMS

Major depressive disorder (MDD) is a prevalent global mental illness with diverse underlying causes. Despite the availability of first-line antidepressants, approximately 10-30 % of MDD patients do not respond to these medications, falling into the category of treatment-resistant depression (TRD). Our study aimed to elucidate the precise molecular mechanisms through which glial cells contribute to depression-like episodes in TRD.

MATERIALS AND METHODS

We conducted a comprehensive literature search using the PubMed and Scopus electronic databases with search terms carefully selected to be specific to our topic. We strictly followed inclusion and exclusion criteria during the article selection process, adhering to PRISMA guidelines. Additionally, we carried out an in-depth analysis of postmortem brain tissue obtained from patients with TRD using single-nucleus transcriptomics (sn-RNAseq).

KEY FINDINGS

Our data confirmed the involvement of multiple glia-specific markers (25 genes) associated with TRD. These differentially expressed genes (DEGs) primarily regulate cytokine signaling, and they are enriched in important pathways such as NFκB and TNF-α. Notably, DEGs showed significant interactions with the transcription factor CREB1. sn-RNAseq analysis confirmed dysregulation of nearly all designated DEGs; however, only Cx30/43, AQP4, S100β, and TNF-αR1 were significantly downregulated in oligodendrocytes (OLGs) of TRD patients. With further exploration, we identified the GLT-1 in OLGs as a hub gene involved in TRD.

SIGNIFICANCE

Our findings suggest that glial dysregulation may hinder the effectiveness of existing therapies for TRD. By targeting specific glial-based genes, we could develop novel interventions with minimal adverse side effects, providing new hope for TRD patients who currently experience limited benefits from invasive treatments.

Neuroprotective effects of coenzyme Q10 on neurological diseases: a review article

Neurological disorders affect the nervous system. Biochemical, structural, or electrical abnormalities in the spinal cord, brain, or other nerves lead to different symptoms, including muscle weakness, paralysis, poor coordination, seizures, loss of sensation, and pain. There are many recognized neurological diseases, like epilepsy, Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), stroke, autosomal recessive cerebellar ataxia 2 (ARCA2), Leber's hereditary optic neuropathy (LHON), and spinocerebellar ataxia autosomal recessive 9 (SCAR9). Different agents, such as coenzyme Q10 (CoQ10), exert neuroprotective effects against neuronal damage. Online databases, such as Scopus, Google Scholar, Web of Science, and PubMed/MEDLINE were systematically searched until December 2020 using keywords, including review, neurological disorders, and CoQ10. CoQ10 is endogenously produced in the body and also can be found in supplements or foods. CoQ10 has antioxidant and anti-inflammatory effects and plays a role in energy production and mitochondria stabilization, which are mechanisms, by which CoQ10 exerts its neuroprotective effects. Thus, in this review, we discussed the association between CoQ10 and neurological diseases, including AD, depression, MS, epilepsy, PD, LHON, ARCA2, SCAR9, and stroke. In addition, new therapeutic targets were introduced for the next drug discoveries.

Spotlight on Coenzyme Q10 in scopolamine-induced Alzheimer's disease: oxidative stress/PI3K/AKT/GSK 3ß/CREB/BDNF/TrKB

OBJECTIVES

Excess amyloid beta (Aβ) and oxidative stress (OS) are inextricable hallmarks of the neuronal damage associated Alzheimer's disease. Aβ-induced cognitive and memory dysfunctions are mediated through different signalling pathways as phosphatidylinositol-3-kinase (PI3K) and their downstream intermediates including protein-kinase-B, known as Akt, glycogen-synthase-kinase-3β (GSK-3β), cAMP-response-element-binding-protein (CREB), brain-derived-neurotrophic factor (BDNF) and tropomyosin-related-kinase receptor-B (TrKB). The current work aims to investigate the protective potentials of CoQ10 against scopolamine (Scop)-induced cognitive disability and the contribution of PI3K/Akt/GSK-3β/CREB/BDNF/TrKB in the neuroprotection effects.

METHODS

The chronic co-administration of CQ10 (50, 100 and 200 mg/kg/day i.p.) with Scop in Wistar rats for 6 weeks were assayed both behaviourally and biochemically.

KEY FINDINGS

CoQ10 ameliorated the Scop-induced cognitive and memory defects by restoring alterations in novel object recognition and Morris water maze behavioural tests. CoQ10 favourably changed the Scop-induced deleterious effects in hippocampal malondialdehyde, 8-hydroxy-2' deoxyguanosine, antioxidants and PI3K/Akt/GSK-3β/CREB/BDNF/TrKB levels.

CONCLUSIONS

These results exhibited the neuroprotective effects of CoQ10 on Scop-induced AD and revealed its ability to inhibit oxidative stress, amyloid deposition and to modulate PI3K/Akt/GSK-3β/CREB/BDNF/TrKB pathway.

PCSK9 Inhibition Reduces Depressive like Behavior in CUMS-Exposed Rats: Highlights on HMGB1/RAGE/TLR4 Pathway, NLRP3 Inflammasome Complex and IDO-1

Ample evidence has pointed to a close link between cardiovascular diseases (CVD) and depression. Inflammatory pathways including the high-mobility-group-box-1 protein, receptor-for-advanced-glycation-end-products and toll-like-receptor-4 (HMGB1/RAGE/TLR4) and nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome pathways are thought to be crucial players in this link. Activation of these pathways ends by releasing of different inflammatory mediators involved in CVD and depression pathophysiology. In the brain, this inflammatory process enhanced indoleamine2,3-dioxygenase-1 (IDO-1) activation with subsequent alteration in kynurenine/tryptophan levels causing depression. Based on the favorable anti-inflammatory effects of Alirocumab, the proprotein-convertase-subtilisin/kexin-type-9 (PCSK9) inhibitor, used in different CVD, this study was designed to investigate its potential antidepressant effect. The behavioral and neurochemical effects of concomitant treatment of Alirocumab at doses of (4, 8 and 16 mg/kg/week subcutaneously) in Wistar rats exposed to chronic unpredictable mild stress (CUMS) for 6 weeks were assayed. Alirocumab prevented CUMS-induced depressive-like-behaviors exhibited in open-field and forced-swimming tests, and hypothalamus-pituitary-adrenal axis hyperactivity (adrenal gland weight and serum corticosterone). Alirocumab prevented CUMS-induced alteration in hippocampal kynurenine/tryptophan levels and pro-inflammatory cytokines tumor-necrosis-factor-alpha, interleukin-1beta (IL-1β), IL-2 and IL-6. Western blot and PCR analysis showed that Alirocumab favorably modulated the HMGB1/RAGE/TLR4 axis, nuclear-factor-kappa-beta, NLRP3 inflammasome complex and IDO-1 in the hippocampus of CUMS rats. These effects were correlated to the level of PCSK9 expression. The behavioral and biochemical findings indicated the potential antidepressant effect of PCSK9 inhibition by Alirocumab.

Polydatin Alleviates Chronic Stress-Induced Depressive and Anxiety-like Behaviors in a Mouse Model

We aimed to investigate whether polydatin could suppress stress-induced depression- and anxiety-like behaviors in a mouse model. Mice were divided into the control group, chronic unpredictable mild stress (CUMS) exposure group, and CUMS mice treated with polydatin group. Following CUMS exposure and polydatin treatment, mice were subjected to behavioral assays to assess depressive-like and anxiety-like behaviors. Synaptic function was determined by the levels of brain-derived neurotrophic factor (BDNF), postsynaptic density protein 95 (PSD95), and synaptophysin (SYN) in the hippocampus and cultured hippocampal neurons. The number and length of dendrites were assessed in cultured hippocampal neurons. Finally, we investigated the effect of polydatin on CUMS-induced inflammation and oxidative stress in the hippocampus by measuring inflammatory cytokine levels, oxidative stress markers such as reactive oxygen species, glutathione peroxidase, catalase, and superoxide dismutase, as well as components of the Nrf2 signaling pathway. Polydatin alleviated CUMS-induced depressive-like behaviors in forced swimming, tail suspension and sucrose preference tests, and anxiety-like behaviors in marble-burying and elevated plus maze tests. Polydatin increased the number and length of dendrites of cultured hippocampal neurons from mice exposed to CUMS and alleviated CUMS-induced synaptic deficits by restoring BDNF, PSD95, and SYN levels in vivo and in vitro. Importantly, polydatin inhibited CUMS-induced hippocampal inflammation and oxidative stress and suppressed the activation of NFκB and Nrf2 pathways. Our study suggests that polydatin may be an effective drug for the treatment of affective disorders through inhibiting neuroinflammation and oxidative stress. Our current findings warrant further study to investigate the potential clinical application of polydatin.

Enriched Environment Attenuates Enhanced Trait Anxiety in Association with Normalization of Aberrant Neuro-Inflammatory Events

Neuroinflammation is discussed to play a role in specific subgroups of different psychiatric disorders, including anxiety disorders. We have previously shown that a mouse model of trait anxiety (HAB) displays enhanced microglial density and phagocytic activity in key regions of anxiety circuits compared to normal-anxiety controls (NAB). Using minocycline, we provided causal evidence that reducing microglial activation within the dentate gyrus (DG) attenuated enhanced anxiety in HABs. Besides pharmacological intervention, "positive environmental stimuli", which have the advantage of exerting no side-effects, have been shown to modulate inflammation-related markers in human beings. Therefore, we now investigated whether environmental enrichment (EE) would be sufficient to modulate upregulated neuroinflammation in high-anxiety HABs. We show for the first time that EE can indeed attenuate enhanced trait anxiety, even when presented as late as adulthood. We further found that EE-induced anxiolysis was associated with the attenuation of enhanced microglial density (using Iba-1 as the marker) in the DG and medial prefrontal cortex. Additionally, EE reduced Iba1 + CD68+ microglia density within the anterior DG. Hence, the successful attenuation of trait anxiety by EE was associated in part with the normalization of neuro-inflammatory imbalances. These results suggest that pharmacological and/or positive behavioral therapies triggering microglia-targeted anti-inflammatory effects could be promising as novel alternatives or complimentary anxiolytic therapeutic approaches in specific subgroups of individuals predisposed to trait anxiety.

Involvement of the gut-brain axis in vascular depression via tryptophan metabolism: A benefit of short chain fatty acids

Cerebral hemodynamic dysfunction and hypoperfusion have been found to underlie vascular depression, but whether the gut-brain axis is involved remains unknown. In this study, a rat model of bilateral common carotid artery occlusion (BCCAO) was adopted to mimic chronic cerebral hypoperfusion. A reduced sucrose preference ratio, increased immobility time in the tail suspension test and forced swim test, and compromised gut homeostasis were found. A promoted conversion of tryptophan (Trp) into kynurenine (Kyn) instead of 5-hydroxytryptamine (5-HT) was observed in the hippocampus and gut of BCCAO rats. Meanwhile, 16S ribosomal RNA gene sequencing suggested a compromised profile of the gut SCFA-producing microbiome, with a decreased serum level of SCFAs revealed by targeted metabolomics analysis. With SCFA supplementation, BCCAO rats exhibited ameliorated depressive-like behaviors and improved gut dysbiosis, compared with the salt-matched BCCAO group. Enzyme-linked immunosorbent assays and quantitative RT-PCR suggested that SCFA supplementation suppressed the conversion of Trp to Kyn and rescued the reduction in 5-HT levels in the hippocampus and gut. In addition to inhibiting the upregulation of inflammatory cytokines, SCFA supplementation ameliorated the activated oxidative stress and reduced the number of microglia and the expression of its proinflammatory markers in the hippocampus post BCCAO. In conclusion, our data suggested the participation of the gut-brain axis in vascular depression, shedding light on the neuroprotective potential of treatment with gut-derived SCFAs.

IDO/kynurenine pathway in cancer: possible therapeutic approaches

Cancer is one of the leading causes of death in both men and women worldwide. One of the main changes associated with cancer progression, metastasis, recurrence, and chemoresistance is the change in the tumor immune microenvironment, especially immunosuppression. Cancer immunosuppression appears in multiple forms, such as inhibition of immuno-stimulant cells with downregulation of immuno-stimulant mediators or through stimulation of immuno-suppressive cells with upregulation of immunosuppressive mediators. One of the most immunosuppressive mediators that approved potency in lung cancer progression is indoleamine 2,3-dioxygenase (IDO) and its metabolite kynurenine (Kyn). The current review tries to elucidate the role of IDO/Kyn on cancer proliferation, apoptosis, angiogenesis, oxidative stress, and cancer stemness. Besides, our review investigates the new therapeutic modalities that target IDO/Kyn pathway and thus as drug candidates for targeting lung cancer and drugs that potentiate IDO/Kyn pathway and thus can be cancer-promoting agents.

Novel role of peroxisome proliferator activated receptor-α in valproic acid rat model of autism: Mechanistic study of risperidone and metformin monotherapy versus combination

Autism spectrum disorder (ASD) is a neurodevelopmental disorder of heterogenous etiology exhibiting a challenge in understanding its exact neuro-pathophysiology. Recently, peroxisome proliferator activated receptor (PPAR)-α activation was found to play a fundamental role in neuroprotection and improving autistic-like-behaviors in experimental animal models of ASD through alleviating neuroinflammation, oxidative-stress, astrocyte reactivity, tauopathy in addition to its favorable role in metabolic regulation, thus attracting attention as a possible target in treatment of ASD. This study aimed to investigate the role of PPAR-α, astrocytic dysfunction and tauopathy in ASD and detect the possible neuroprotective effects of metformin (MET), through PPAR-α activation, and risperidone (RIS) either monotherapy or in combination in alleviating autistic-like-changes at behavioral and neurobiological levels in male Wistar rats. Pregnant female Wistar rats received valproic-acid (VPA) to induce autistic-like-behavioral and neurobiological alterations in their offspring. Chronic intra-peritoneal MET (100 mg/kg/day) and RIS (1 mg/kg/day) either monotherapy or in combination started from postnatal day (PND) 24 till PND61 (38 days). Prenatal VPA exposure simulated the autistic core behaviors associated with neurochemical and histopathological neurodevelopmental degenerative changes. Both MET and RIS either monotherapy or in combination were able to reverse these changes. The effect of MET was comparable to RIS. Moreover, MET was able to alleviate the RIS induced weight gain and improve cognitive functions highlighting its promising adjunctive role in alleviating ASD pathophysiology. Our study highlighted the favorable effects of MET and RIS both in monotherapy and in combination in alleviating the autistic-like-changes and proposed PPAR-α activation along with restoring astrocytes homeostasis as promising targets in novel therapeutic strategies in ASD.

Indoleamine-2,3-Dioxygenase as a Perioperative Marker of the Immune System

Indoleamine-2,3-dioxygenase (IDO) is the “rate-limiting” enzyme in the kynurenine (Kyn) pathway of the tryptophan (Trp) catabolism. By its immune-modulatory effect, IDO initiates changes to the physiologically balanced immune state and plays a key role in the pathogenesis of various diseases, as well as in the perioperative setting during surgery. In autoimmune processes, highly malignant cancers such as glioblastoma or organ transplantation, IDO’s involvement has been studied extensively. However, in severe systemic infections, as present in sepsis, it is not yet completely understood. Hereafter, in this narrative review, we present the current knowledge of IDO’s implication on such complex immune-related processes. Moreover, we address the role of IDO as a predictive biomarker as well as a therapeutic target for immune-mediated diseases. Finally, we discuss IDO in the setting of surgical trauma-induced stress and highlight its promising use as a biomarker in the pre-operative setting for all disciplines involved in the decision-making process and treatment of patients undergoing surgery.

Coenzyme Q10 a mitochondrial restorer for various brain disorders

Coenzyme Q10 (ubiquinone or CoQ10) is a lipid molecule that acts as an electron mobile carrier of the electron transport chain and also contains antioxidant properties. Supplementation of CoQ10 has been very useful to treat mitochondrial diseases. CoQ10 along with its synthetic analogue, idebenone, is used largely to treat various neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis, and Friedreich's ataxia and additional brain disease condition like autism, multiple sclerosis, epilepsy, depression, and bipolar disorder, which are related to mitochondrial impairment. In this article, we have reviewed numerous physiological functions of CoQ10 and the rationale for its use in clinical practice in different brain disorders.

Neurotoxic Effect of Fipronil in Male Wistar Rats: Ameliorative Effect of L-Arginine and L-Carnitine

Simple Summary

Insecticides are widely used in agricultural and household environments. They induce wide range of deleterious effects. Fipronil is one of the most widely used phenylpyrazoles insecticides. The neurotoxic effect of such insecticide was tested in the present study with special emphasis on cognitive deficit as well as testing the possible ameliorative impacts of L-arginine and L-carnitine. The study proposed fipronil-induced cognitive deficit as a reflection to oxidative stress and neuro-inflammation. Moreover, L-arginine and L-carnitine exerted ameliorative influence on fipronil induced oxidative stress and neuro-inflammation. Therefore, L-arginine and L-carnitine can be considered as prospective candidates for mitigation of pesticide induced neurotoxicity especially in people with high-risk exposure to pesticide.

Abstract

The ameliorative effect of L-arginine (LA) and L-carnitine (LC) against fipronil (FPN)-induced neurotoxicity was explored. In this case, 36 adult male rats were randomly divided into six groups: group I received distilled water, group II received 500 mg/kg LA, group III received 100 mg/kg LC, group IV received 4.85 mg/kg FPN, group V received 4.85 mg/kg FPN and 500 mg/kg LA and group VI received 4.85 mg/kg FPN and 100 mg/kg LC for 6 weeks. Cognitive performance was assessed using Barnes maze (BM). Serum corticosterone, brain total antioxidant capacity (TAC), malondialdehyde (MDA) and dopamine were measured. Histopathology and immunohistochemistry of ionized calcium-binding adaptor (Iba-1), doublecortin (DCX) and serotonin (S-2A) receptors were performed. Fipronil induced noticeable deterioration in spatial learning and memory performance. In addition, FPN significantly (p < 0.05) diminished brain antioxidant defense system and dopamine coincide with elevated serum corticosterone level. Histopathological examination revealed degenerative and necrotic changes. Furthermore, Iba-1 and DCX were significantly expressed in cortex and hippocampus whereas S-2A receptors were significantly lowered in FPN group. However, administration of LA or LC alleviated FPN-induced deteriorations. In conclusion, LA and LC could be prospective candidates for mitigation of FPN-induced neurotoxicity via their antioxidant, anti-inflammatory and neuropotentiating effects.

Grape seed proanthocyanidins improves depression-like behavior by alleviating oxidative stress and NLRP3 activation in the hippocampus of prenatally-stressed female offspring rats

Over several decades, there is a growing evidence, which has shown that prenatal stress (PS) contributes to depression in offspring. Grape seed proanthocyanidins (GSPs), which contain dimers, trimers, oligomers of catechin and epicatechin, are known to possess antidepressant effects. The present study aimed to investigate the mechanism of antidepressant effects of GSPs on female juvenile prenatally stressed offspring rats. The results showed that the female juvenile offspring rats exposed to PS exhibited depression-like behavior manifested as longer immobility time and lesser consumption of sucrose solution. Prenatal stress reduced the number of hippocampal neurons and increased the level of the reactive oxygen species (ROS) in the hippocampus of the female juvenile offspring rats. Furthermore, the expression of PYD domains-containing protein 3 (NLRP3) and its downstream cytokines, Caspase-1, and interleukin-1β (IL-1β), were increased in the hippocampus of the female juvenile offspring rats exposed to PS. Administration of GSPs not only improved depression-like behavior and enhanced the number of hippocampal neurons, but also abated excessive ROS generation and inhibited the activation of the NLRP3-Caspase-1 signaling pathway. Taken together, GSPs counteract PS-induced hippocampal neuron loss and depression-like behavior by alleviating oxidative stress and NLRP3 activation. The present study provides a new insight for GSPs as an effective therapeutic agent for adolescent depression.

Natural volatile oils derived from herbal medicines: A promising therapy way for treating depressive disorder

Depression is a common global mental disorder that seriously harms human physical and mental health. With the development of society, the increase of pressure and the role of various other factors make the incidence of depression increase year by year. However, there is a lack of drugs that have a fast onset, significant effects, and few side effects. Some volatile oils from traditional natural herbal medicines are usually used to relieve depression and calm emotions, such as Lavender essential oil and Acorus tatarinowii essential oil. It was reported that these volatile oils, are easy to enter the brain through the blood-brain barrier and have good antidepressant effects with little toxicity and side effects. In this review, we summarized the classification of depression, and listed the history of using volatile oils to fight depression in some countries. Importantly, we summarized the anti-depressant natural volatile oils and their monomers from herbal medicine, discussed the anti-depressive mechanisms of the volatile oils from natural medicine. The volatile oils of natural medicine and antidepressant drugs were compared and analyzed, and the application of volatile oils was explained from the clinical use and administration routes. This review would be helpful for the development of potential anti-depressant medicine and provide new alternative treatments for depressive disorders.

Physiological and Proteomic Analysis of Penicillium digitatum in Response to X33 Antifungal Extract Treatment

Penicillium digitatum is a widespread pathogen among Rutaceae species that causes severe fruit decay symptoms on infected citrus fruit (known as citrus green mold). The employment of fungicides can effectively control the citrus green mold, significantly reducing agricultural economic loss. In this study, we found that the X33 antifungal extract produced by Streptomyces lavendulae strain X33 inhibited the hyphae polarization of P. digitatum. Additionally, physiological and proteomic analysis strategies were applied to explore the inhibitory mechanism of the X33 antifungal extract of the S. lavendulae strain X33 on the mycelial growth of P. digitatum. A total of 277 differentially expressed proteins, consisting of 207 upregulated and 70 downregulated, were identified from the comparative proteomics analysis. The results indicated that the X33 antifungal extract induced mitochondrial membrane dysfunction and cellular integrity impairment, which can affect energy metabolism, oxidative stress, and transmembrane transport. The improved alkaline phosphatase activity and extracellular conductivity, increased H₂O₂ and malondialdehyde contents, and inhibition of energy, amino acid, and sugar metabolism indicated that the oxidative stress of P. digitatum is induced by the X33 antifungal extract. These findings provided insight into the antifungal mechanism of the X33 antifungal extract against P. digitatum by suggesting that it may be an effective fungicide for controlling citrus postharvest green mold.

Adaptogenic effects of curcumin on depression induced by moderate and unpredictable chronic stress in mice

Curcumin has been investigated for the prevention and treatment of diseases due to its anti-oxidant, anti-inflammatory, immunomodulatory, and neuroprotective actions. This current study evaluated the adaptogenic effects of a subchronic oral administration of curcumin to Swiss mice that were submitted to a chronic unpredictable mild stress (CUMS) model of depression. Four groups of mice (vehicle control, CO; curcumin control, COC; CUMS + vehicle, CUMS; CUMS + curcumin, CUMSC) were evaluated for the biochemical parameters. The CUMS model caused depressive-like and anxiety-like behavior in the animals when they were viewed in the Forced Swimming Test and in the Elevated Plus Maze Test. The treatments with curcumin prevented the depressive-like behavior in the Forced Swimming Test and they had anxiolytic effects on the non-stressed animals. This was confirmed by the Elevated Plus Maze Test. Curcumin showed antioxidant effects (IC₅₀ of 38.86 ± 1.78 μg/mL) in the in vitro DPPH (2,2-diphenyl-1-picryl-hydrozole) test. The compound also showed antioxidant effects in vivo, increasing the catalase (CAT) levels in the brains of the stressed animals. The biochemical analyses did not reveal potential renal and hepatic damage. Together, these results have demonstrated the antidepressant and antioxidant effects of curcumin, highlighting in this mice model, the compound's novel adaptogenic potential.

Kynurenine regulates NLRP2 inflammasome in astrocytes and its implications in depression

Increased kynurenine (Kyn) metabolized from tryptophan (Try) is a biomarker in the immune dysfunction of depression. However, the mechanism by which Kyn change promotes depression is poorly defined. Astrocytes are involved in the neuroinflammation of depression. Among the numerous inflammatory cytokines, interleukin-1β (IL-1β) produced by astrocytic Nod-like receptor protein (NLRP) inflammasome is crucial in the pathogenesis of depression. In the present study, Kyn was shown to be a proinflammatory metabolite in the neuroimmune signaling network mediating depressive-like behavior. First, in chronic mild stress (CMS)-induced depressive mice, the level of Kyn notably increased in the hippocampus, accompanied by the activation of astrocytic NLRP2 inflammasome. Kyn treatment specifically upregulated Nod-like receptor protein 2 (NLPR2) expression in primary mouse astrocytes. Kyn + ATP activated NLRP2 inflammasome, evidenced by increased caspase-1 expression and IL-1β release. After Kyn treatment, nuclear factor kappa-B (NF-κB) could translocate to the nucleus and bind the promoter of NLRP2, subsequently increased NLRP2 transcription in cultured astrocytes in vitro. Intraperitoneal injection of Kyn activated NLRP2 inflammasome in astrocytes of hippocampus in mice, while NLRP2 knockdown in astrocytes abolished depressive-like behaviors in mice induced by Kyn, suggesting the critical role of NLRP2 in Kyn-induced depression. These findings demonstrate a novel mechanism that Kyn upregulates NLRP2 in an NF-κB-dependent pathway and provide a new strategy for treatment of depression.

Neuroinflammatory alterations in trait anxiety: modulatory effects of minocycline

High trait anxiety is a substantial risk factor for developing anxiety disorders and depression. While neuroinflammation has been identified to contribute to stress-induced anxiety, little is known about potential dysregulation in the neuroinflammatory system of genetically determined pathological anxiety or high trait anxiety individuals. We report microglial alterations in various brain regions in a mouse model of high trait anxiety (HAB). In particular, the dentate gyrus (DG) of the hippocampus of HABs exhibited enhanced density and average cell area of Iba1+, and density of phagocytic (CD68+/Iba1+) microglia compared to normal anxiety (NAB) controls. Minocycline was used to assess the capacity of a putative microglia 'inhibitor' in modulating hyperanxiety behavior of HABs. Chronic oral minocycline indeed reduced HAB hyperanxiety, which was associated with significant decreases in Iba1+ and CD68+Iba1+ cell densities in the DG. Addressing causality, it was demonstrated that longer (10 days), but not shorter (5 days), periods of minocycline microinfusions locally into the DG of HAB reduced Iba-1+ cell density and attenuated hyperanxiety-related behavior, indicating that neuroinflammation in the DG is at least partially involved in the maintenance of pathological anxiety. The present data reveal evidence of disturbances in the microglial system of individuals with high trait anxiety. Minocycline attenuated HAB hyperanxiety, likely by modulation of microglial activity within the DG. Thus, the present data suggest that drugs with microglia-targeted anti-inflammatory properties could be promising as novel alternative or complimentary anxiolytic therapeutic approaches in specific subgroups of individuals genetically predisposed to hyperanxiety.

Tadalafil versus linaclotide in gastrointestinal dysfunction and depressive behavior in constipation-predominant irritable bowel syndrome

BACKGROUND

Intestinal GC-C/cGMP pathway may be involved in visceral hypersensitivity and fluid secretion in irritable bowel syndrome (IBS). The guanylcyclase C agonist linaclotide, approved for IBS- constipation, is contraindicated in children as it may cause severe diarrhea. In contrast, drugs increasing cGMP by inhibiting phosphodiesterase 5 (PDE-5) are well tolerated in children with pulmonary hypertension. Accordingly, we investigated whether beneficial effects of linaclotide in IBS might be shared by PDE-5inhibitor tadalafil without the severe diarrhea reported for linaclotide. Since depression is commonly comorbid with IBS and is implicated in its pathophysiology; and since tadalafil is absorbed systemically and crosses blood brain barrier, whereas linaclotide does not, impact of both drugs on behavioral changes in IBS was also investigated.

METHODS

72 rats were divided into 6groups (control naive, control tadalafil, control linaclotide, untreated IBS, IBS tadalafil, and IBS linaclotide-treated). IBS was induced by 0 to 4 °C intragastric saline for 14 days.

RESULTS

Both drugs reduced visceral hypersensitivity and colonic C fos. Tadalafil, and to a greater extent, linaclotide increased colonic cGMP, fecal pellets (8.66 ± 4.6 (IBS),versus14.8 ± 3.3(tadalafil), 20 ± 1.2(linaclotide), fecal water content (29.8 ± 5.5 (IBS), versus 47.83 ± 12.6 (tadalafil), 63.58 ± 11.6 (linaclotide) and reduced intestinal transit time (% distance travelled: 29 ± 6.1(IBS), versus 40.58 + 7.5(tadalafil), 51.83 ± 8.3(linaclotide). Tadalafil, but not linaclotide, increased hippocampal cGMP, and improved behavioral tests scores compared to linaclotide (immobility time: 97.3 ± 12.5 s (IBS) versus 68 ± 12.8(tadalafil), 80 ± 17.06 (linaclotide).

CONCLUSION

Systemic PDE-5 inhibitors might be alternatives to locally acting guanyl cyclase agonists in IBS, inducing less severe diarrhea and more beneficial effects on the associated behavioral changes.

Targeting Inflammatory-Mitochondrial Response in Major Depression: Current Evidence and Further Challenges

The prevalence of psychiatric disorders has increased in recent years. Among existing mental disorders, major depressive disorder (MDD) has emerged as one of the leading causes of disability worldwide, affecting individuals throughout their lives. Currently, MDD affects 15% of adults in the Americas. Over the past 50 years, pharmacotherapy, psychotherapy, and brain stimulation have been used to treat MDD. The most common approach is still pharmacotherapy; however, studies show that about 40% of patients are refractory to existing treatments. Although the monoamine hypothesis has been widely accepted as a molecular mechanism to explain the etiology of depression, its relationship with other biochemical phenomena remains only partially understood. This is the case of the link between MDD and inflammation, mitochondrial dysfunction, and oxidative stress. Studies have found that depressive patients usually exhibit altered inflammatory markers, mitochondrial membrane depolarization, oxidized mitochondrial DNA, and thus high levels of both central and peripheral reactive oxygen species (ROS). The effect of antidepressants on these events remains unclear. Nevertheless, the effects of ROS on the brain are well known, including lipid peroxidation of neuronal membranes, accumulation of peroxidation products in neurons, protein and DNA damage, reduced antioxidant defenses, apoptosis induction, and neuroinflammation. Antioxidants such as ascorbic acid, tocopherols, and coenzyme Q have shown promise in some depressive patients, but without consensus on their efficacy. Hence, this paper provides a review of MDD and its association with inflammation, mitochondrial dysfunction, and oxidative stress and is aimed at thoroughly discussing the putative links between these events, which may contribute to the design and development of new therapeutic approaches for patients.

EPA is More Effective than DHA to Improve Depression-Like Behavior, Glia Cell Dysfunction and Hippcampal Apoptosis Signaling in a Chronic Stress-Induced Rat Model of Depression

Clinical evidence indicated that eicosapentaenoic acid (EPA) was more effective than docosahexaenoic acid (DHA) in depression treatment. However, possible mechanisms remain unclear. Here, a chronic unpredictable mild stress (CUMS)-induced model of depression was used to compare EPA and DHA anti-depressant effects. After EPA or DHA feeding, depression-like behavior, brain n-3/n-6 PUFAs profile, serum corticosterone and cholesterol concentration, hippocampal neurotransmitters, microglial and astrocyte related function, as well as neuronal apoptosis and survival signaling pathways were studied. EPA was more effective than DHA to ameliorate CUMS-induced body weight loss, and depression-like behaviors, such as increasing sucrose preference, shortening immobility time and increasing locomotor activity. CUMS-induced corticosterone elevation was reversed by bother fatty acids, while increased cholesterol was only reduced by EPA supplement. Lower hippocampal noradrenaline and 5-hydroxytryptamine concentrations in CUMS rats were also reversed by both EPA and DHA supplement. However, even though CUMS-induced microglial activation and associated increased IL-1β were inhibited by both EPA and DHA supplement, increased IL-6 and TNF-α levels were only reduced by EPA. Compared to DHA, EPA could improve CUMS-induced suppressive astrocyte biomarkers and associated BDNF-TrkB signaling. Moreover, EPA was more effective than DHA to attenuate CUMS-induced higher hippocampal NGF, GDNF, NF-κB, p38, p75, and bax expressions, but reversed bcl-2 reduction. This study for the first time revealed the mechanisms by which EPA was more powerful than DHA in anti-inflammation, normalizing astrocyte and neurotrophin function and regulating NF-κB, p38 and apoptosis signaling. These findings reveal the different mechanisms of EPA and DHA in clinical depression treatment.

Coenzyme Q10 supplementation reduces peripheral oxidative stress and inflammation in interferon-β1a-treated multiple sclerosis

Background:

Oxidative stress is a driver of multiple sclerosis (MS) pathology. We evaluated the effect of coenzyme Q10 (CoQ10) on laboratory markers of oxidative stress and inflammation, and on MS clinical severity.

Methods:

We included 60 relapsing–remitting patients with MS treated with interferon beta1a 44μg (IFN-β1a) with CoQ10 for 3 months, and with IFN-β1a 44μg alone for 3 more months (in an open-label crossover design). At baseline and at the 3 and 6-month visits, we measured markers of scavenging activity, oxidative damage and inflammation in the peripheral blood, and collected data on disease severity.

Results:

After 3 months, CoQ10 supplementation was associated with improved scavenging activity (as mediated by uric acid), reduced intracellular reactive oxygen species production, reduced oxidative DNA damage, and a shift towards a more anti-inflammatory milieu in the peripheral blood [with higher interleukin (IL)-4 and IL-13, and lower eotaxin, granulocyte-macrophage colony-stimulating factor (GM-CSF), hepatocyte growth factor (HGF), interferon (IFN)-γ, IL-1α, IL-2R, IL-9, IL-17F, macrophage inflammatory proteins (MIP)-1α, regulated on activation-normal T cell expressed and secreted (RANTES), tumor necrosis factor (TNF)-α, and vascular endothelial growth factor (VEGF). Also, CoQ10 supplementation was associated with lower Expanded Disability Status Scale, fatigue severity scale, Beck’s depression inventory, and the visual analogue scale for pain.

Conclusions:

CoQ10 supplementation improved scavenging activity, reduced oxidative damage, and induced a shift towards a more anti-inflammatory milieu, in the peripheral blood of relapsing–remitting MS patients treated with 44μg IFN-β1a 44μg. A possible clinical effect was noted but deserves to be confirmed over longer follow ups.

IDO and TDO as a potential therapeutic target in different types of depression

Depression is highly prevalent worldwide and a leading cause of disabilty. However, the medications currently available to treat depression fail to adequately relieve depressive symptoms for a large number of patients. Research into the aberrant overactivation of the kynurenine pathway and the production of various active metabolites has brought new insight into the progression of depression. IDO and TDO are the first and rate-limiting enzymes in the kynurenine pathway and regulate the production of active metabolites. There is substantial evidence that TDO and IDO enzyme are activated during depression, and therefore, IDO and TDO inhibitors have been identified as ideal therapeutic targets for depressive disorder. Hence, this review will focus on the kynurenine branch of tryptophan metabolism and describe the role of IDO and TDO in the pathology of depression. In addition, this review will compare the relative imbalance between KYNA and neurotoxic kynurenine metabolites in different psychiatric disorders. Finally, this review is also directed toward assessing whether IDO and TDO are potential therapeutic target in depression associated with other diseases such as diabetes and/or cancer, as well as the development of potent IDO and TDO inhibitors.

Effect of Metabolic Stress on Lysosomal Proteolysis in the Liver and Brain of Rats Receiving Q10-Enriched Ration

Activation of lysosomal proteolysis and increased coenzyme Q10 level were revealed in the liver and brain of rats with individual typological features under conditions of food deprivation. Changes in cathepsin B activity in these tissues were different in behaviorally active and passive animals. We observed indirect modulating effect of coenzyme Q10 in the regulation of activity of lysosomal endopeptidases in the brain of animals with different behavior during adaptation to metabolic stress.

An Expanded Neuroimmunomodulation Axis: sCD83-Indoleamine 2,3-Dioxygenase-Kynurenine Pathway and Updates of Kynurenine Pathway in Neurologic Diseases

Many neurologic diseases are related to autoimmune dysfunction and a variety of molecules or reaction pathways are involved in the regulation of immune function of the nervous system. Soluble CD83 (sCD83) is the soluble form of CD83, a specific marker of mature dendritic cell, which has recently been shown to have an immunomodulatory effect. Indoleamine 2,3-dioxygenase (IDO; corresponding enzyme intrahepatic, tryptophan 2,3-dioxygenase, TDO), a rate-limiting enzyme of extrahepatic tryptophan kynurenine pathway (KP) participates in the immunoregulation through a variety of mechanisms solely or with the synergy of sCD83, and the imbalances of metabolites of KP were associated with immune dysfunction. With the complement of sCD83 to IDO-KP, a previously known immunomodulatory axis, this review focused on an expanded neuroimmunomodulation axis: sCD83-IDO-KP and its involvement in nervous system diseases.

The potential benefit of combined versus monotherapy of coenzyme Q10 and fluoxetine on depressive-like behaviors and intermediates coupled to Gsk-3β in rats

As a part of the serotoninergic dysfunction implicated in neurobiology of depression, evidence has focused on serotonin (5-HT) receptors downstream signaling intermediates including glycogen synthase kinase-3β (GSK-3β), cAMP response element binding protein (CREB) and brain derived neurotrophic factor (BDNF). Our team previously reported that coenzyme Q10 (CoQ10) exerted antidepressant-like effect in rats exposed to chronic unpredictable mid stress (CUMS) via elevating serotonin levels. However, the effect of CoQ10 has not been elucidated in downstream signaling molecules mediating 5HT receptors' effect involved in depressive disorder hitherto. In the present study, we focused on 5-HT_1A and 5-HT_2A receptors (activation of 5-HT_1A receptor and inhibition of 5-HT_2A receptors reduce depressive like-behaviors). We investigated the role of these 5-HT receptors and their linked GSK-3β signaling intermediates as an underlying mechanism of CoQ10 as monotherapy or combined with fluoxetine, a selective serotonin reuptake inhibitor, to alleviate depressive-like phenotype. Effects of CoQ10 (100mg/kg/day) or/and fluoxetine (10mg/kg/day) were determined on 5-HT_1A, 5-HT_2A receptors mRNA expression, GSK-3β and phosphorylated (p)GSK-3β, CREB, pCREB and BDNF protein expression in rats subjected to CUMS for 6weeks. CUMS rats exhibited obvious depressive-like behaviors (anhedonia-like behavior, negative alterations in social interaction, open field and forced swimming tests) with increased corticosterone and adrenal glands weight, decreased hippocampal levels of pGSK-3β, pCREB and BDNF protein expressions. Additionally, they exhibited decreased hippocampal 5-HT_1A and increased 5-HT_2A receptor mRNA expression. CoQ10 or fluoxetine significantly attenuated the behavioral and neurochemical alterations in stressed rats with more significance with combined treatment. These findings imply that CoQ10 or/and fluoxetine attenuated CUMS-induced depressive-like behavior partly through modulating dysfunctional regulation of post-serotonergic receptor signaling pathway focusing on GSK-3β, CREB and BDNF.