Minocycline in neurodegenerative and psychiatric diseases: An update

N-Cinnamoylpyrrole-derived alkaloids from the genus Piper as promising agents for ischemic stroke by targeting eEF1A1

BACKGROUND

Ischemic stroke (IS) is a serious cerebrovascular disease characterized by significantly elevated mortality and disability rates, and the treatments available for this disease are limited. Neuroinflammation and oxidative stress are deemed the major causes of cerebral ischemic injury. N-Cinnamoylpyrrole alkaloids form a small group of natural products from the genus Piper and have not been extensively analyzed pharmacologically. Thus, identifying the effect and mechanism of N-cinnamoylpyrrole-derived alkaloids on IS is worthwhile.

PURPOSE

The present research aimed to explore the antineuroinflammatory and antioxidative stress effects of N-cinnamoylpyrrole-derived alkaloids isolated from the genus Piper and to explain the effects and mechanism on IS.

METHODS

N-cinnamoylpyrrole-derived alkaloids were isolated from Piper boehmeriaefolium var. tonkinense and Piper sarmentosum and identified by various chromatographic methods. Lipopolysaccharide (LPS)-induced BV-2 microglia and a mouse model intracerebroventricularly injected with LPS were used to evaluate the antineuroinflammatory and antioxidative stress effects. Oxygen‒glucose deprivation/reperfusion (OGD/R) and transient middle cerebral artery occlusion (tMCAO) models were used to evaluate the effect of PB-1 on IS. To elucidate the fundamental mechanism, the functional target of PB-1 was identified by affinity-based protein profiling (ABPP) strategy and verified by cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS), and circular dichroism (CD) analyses. The effect of PB-1 on the NF-κB and NRF2 signaling pathways was subsequently evaluated via western blotting and immunofluorescence staining.

RESULTS

The results showed that N-cinnamoylpyrrole-derived alkaloids significantly affected neuroinflammation and oxidative stress. The representative compound, PB-1 not only inhibited neuroinflammation and oxidative stress induced by LPS or OGD/R insult, but also alleviated cerebral ischemic injury induced by tMCAO. Further molecular mechanism research found that PB-1 promoted antineuroinflammatory and antioxidative stress activities via the NF-κB and NRF2 signaling pathways by targeting eEF1A1.

CONCLUSION

Our research initially unveiled that the therapeutic impact of PB-1 on cerebral ischemic injury might rely on its ability to target eEF1A1, leading to antineuroinflammatory and antioxidative stress effects. The novel discovery highlights eEF1A1 as a potential target for IS treatment and shows that PB-1, as a lead compound that targets eEF1A1, may be a promising therapeutic agent for IS.

Minocycline protects against lipopolysaccharide-induced glial cells activation and oxidative stress damage in the medial prefrontal cortex (mPFC) of the rat

PURPOSE/AIM

Neuroinflammation and oxidative stress have been encountered in neurodegenerative diseases such as Alzheimer's disease (AD). However, the neuroprotective effects of minocycline against lipopolysaccharide (LPS)-induced glial cells activation and oxidative stress damage in the medial prefrontal cortex (mPFC) of rats are still elusive. The purpose of this study is to investigate the effects of minocycline and memantine, an N-methyl-D-aspartate (NMDA) receptor antagonist, on the microglia and astrocytes expression, as well as oxidative stress levels in the mPFC of LPS injected rats.

MATERIALS AND METHODS

Fifty adult Male Sprague Dawley rats were divided into five groups: control, LPS (5 mg/kg), LPS treated with minocycline (25 mg/kg), LPS treated with minocycline (50 mg/kg) and LPS treated with memantine (10 mg/kg). The immunohistochemistry and western blotting were used to analyse the expressions and densities of microglia marker (Iba-1) and astrocyte marker, (GFAP) while enzyme-linked immunosorbent assay (ELISA) was used to measure the protein carbonyl (PCO), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD) levels.

RESULTS

In comparison to the control group, the expression and density of Iba-1 and GFAP were significantly enhanced in the LPS group (p < 0.05). LPS group also exhibited significantly higher levels of PCO and MDA (p < 0.05) and significantly lower levels of CAT and SOD (p < 0.05) when compared to the control group. Both minocycline and memantine-treated LPS rats were able to protect against these effects.

CONCLUSION

Minocycline, like memantine treatment, reduces oxidative stress in the mPFC of LPS rats via inhibition of glial cells activation.

Promising immunomodulators for management of substance and alcohol use disorders

INTRODUCTION

The neuroimmune system has emerged as a novel target for the treatment of substance use disorders (SUDs), with immunomodulation producing encouraging therapeutic benefits in both preclinical and clinical settings.

AREAS COVERED

In this review, we describe the mechanism of action and immune response to methamphetamine, opioids, cocaine, and alcohol. We then discuss off-label use of immunomodulators as adjunctive therapeutics in the treatment of neuropsychiatric disorders, demonstrating their potential efficacy in affective and behavioral disorders. We then discuss in detail the mechanism of action and recent findings regarding the use of ibudilast, minocycline, probenecid, dexmedetomidine, pioglitazone, and cannabidiol to treat (SUDs). These immunomodulators are currently being investigated in clinical trials described herein, specifically for their potential to decrease substance use, withdrawal severity, central and peripheral inflammation, comorbid neuropsychiatric disorder symptomology, as well as their ability to improve cognitive outcomes.

EXPERT OPINION

We argue that although mixed, findings from recent preclinical and clinical studies underscore the potential benefit of immunomodulation in the treatment of the behavioral, cognitive, and inflammatory processes that underlie compulsive substance use.

Minocycline mitigates tau pathology via modulating the TLR-4/NF-кβ signalling pathway in the hippocampus of neuroinflammation rat model

INTRODUCTION

The neuroinflammatory response was seen to impact the formation of phosphorylated tau protein in Alzheimer's disease (AD). This study aims to investigate the molecular mechanism of minocycline in reducing phosphorylated tau protein formation in the hippocampus of lipopolysaccharide (LPS)-induced rats.

METHODS

Fifty adult male Sprague Dawley (SD) rats were randomly allocated to 1 of 5 groups: control, LPS (5 mg/kg), LPS + minocycline (25 mg/kg), LPS + minocycline (50 mg/kg) and LPS + memantine (10 mg/kg). Minocycline and memantine were administered intraperitoneally (i.p) for two weeks, and LPS was injected i.p. once on day 5. ELISA was used to determine the level of phosphorylated tau protein in SD rats' hippocampal tissue. The density and expression of Toll-like receptor-4 (TLR-4), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-кβ), tumour necrosis factor-alpha (TNF-α), and cyclooxygenase (COX)-2 were determined using Western blot and immunohistochemistry.

RESULTS

Minocycline, like memantine, prevented LPS-induced increasein phosphorylated tau protein level suggested via reduced density and expression of TLR-4, NF-кβ, TNF-αand COX-2 proteins in rat hippocampal tissue. Interestingly, higher doses were shown to be more neuroprotective than lower doses.

CONCLUSION

This study suggests that minocycline suppresses the neuroinflammation signalling pathway and decreased phosphorylated tau protein formation induced by LPS in a dose-dependent manner. Minocycline can be used as a preventative and therapeutic drug for neuroinflammatory diseases such as AD.

The microbiota-gut-brain axis in Huntington's disease: pathogenic mechanisms and therapeutic targets

Huntington's disease (HD) is a currently incurable neurogenerative disorder and is typically characterized by progressive movement disorder (including chorea), cognitive deficits (culminating in dementia), psychiatric abnormalities (the most common of which is depression), and peripheral symptoms (including gastrointestinal dysfunction). There are currently no approved disease-modifying therapies available for HD, with death usually occurring approximately 10-25 years after onset, but some therapies hold promising potential. HD subjects are often burdened by chronic diarrhea, constipation, esophageal and gastric inflammation, and a susceptibility to diabetes. Our understanding of the microbiota-gut-brain axis in HD is in its infancy and growing evidence from preclinical and clinical studies suggests a role of gut microbial population imbalance (gut dysbiosis) in HD pathophysiology. The gut and the brain can communicate through the enteric nervous system, immune system, vagus nerve, and microbiota-derived-metabolites including short-chain fatty acids, bile acids, and branched-chain amino acids. This review summarizes supporting evidence demonstrating the alterations in bacterial and fungal composition that may be associated with HD. We focus on mechanisms through which gut dysbiosis may compromise brain and gut health, thus triggering neuroinflammatory responses, and further highlight outcomes of attempts to modulate the gut microbiota as promising therapeutic strategies for HD. Ultimately, we discuss the dearth of data and the need for more longitudinal and translational studies in this nascent field. We suggest future directions to improve our understanding of the association between gut microbes and the pathogenesis of HD, and other 'brain and body disorders'.

Between Dysbiosis, Maternal Immune Activation and Autism: Is There a Common Pathway?

Autism spectrum disorder (ASD) is a neuropsychiatric condition characterized by impaired social interactions and repetitive stereotyped behaviors. Growing evidence highlights an important role of the gut-brain-microbiome axis in the pathogenesis of ASD. Research indicates an abnormal composition of the gut microbiome and the potential involvement of bacterial molecules in neuroinflammation and brain development disruptions. Concurrently, attention is directed towards the role of short-chain fatty acids (SCFAs) and impaired intestinal tightness. This comprehensive review emphasizes the potential impact of maternal gut microbiota changes on the development of autism in children, especially considering maternal immune activation (MIA). The following paper evaluates the impact of the birth route on the colonization of the child with bacteria in the first weeks of life. Furthermore, it explores the role of pro-inflammatory cytokines, such as IL-6 and IL-17a and mother's obesity as potentially environmental factors of ASD. The purpose of this review is to advance our understanding of ASD pathogenesis, while also searching for the positive implications of the latest therapies, such as probiotics, prebiotics or fecal microbiota transplantation, targeting the gut microbiota and reducing inflammation. This review aims to provide valuable insights that could instruct future studies and treatments for individuals affected by ASD.

Minocycline in depression not responding to first-line therapy: A systematic review and meta-analysis

BACKGROUND

Major depressive disorder is often resistant to first-line treatment, with around 30% failing to respond to traditional therapy. Treatment-resistant depression results in prolonged hospitalization and healthcare costs. Anti-inflammatory drugs have shown promising results in depression not responding to initial therapy. Minocycline has anti-inflammatory properties and crosses the blood-brain barrier. It has demonstrated varied results in several randomized controlled trials (RCTs).

METHODS

We assessed the efficacy of minocycline compared to placebo in depression not responding to one first-line antidepressant via a systematic review and meta-analysis. We performed a comprehensive literature search across PubMed, Cochrane, and Scopus for RCTs. We visualized the results using forest plots and drapery plots. We assessed and explored heterogeneity using I2, prediction interval, and meta-regression. Then, we rated the certainty of the evidence.

RESULTS

Four RCTs revealed a non-significant difference in depression severity [-3.93; 95% CI: -16.14 to 8.28], rate of response [1.15; 0.33-4.01], and rate of remission [0.94; 0.44-2.01]. However, the reduction in depression severity is significant at a trend of P < .1. The high between-study heterogeneity (I2 = 78%) for depression severity could be answered by meta-regression (P = .02) for the duration of therapy.

CONCLUSION

There is no significant difference with minocycline compared to placebo for depression not responding to first-line antidepressant therapy. However, the treatment response varies with treatment duration and patients' neuroinflammatory state. Thus, larger and longer RCTs, especially in diverse disease subgroups, are needed for further insight. This is needed to allow greater precision medicine in depression and avoid elevated healthcare expenditure associated with hit-and-trial regimens.

REGISTRATION

CRD42023398476 (PROSPERO).

Mechanisms associated with post-stroke depression and pharmacologic therapy

Stroke is one of the most common cerebrovascular diseases, which is the cause of long-term mental illness and physical disability, Post-stroke depression (PSD) is the most common neuropsychiatric complication after stroke, and its mechanisms are characterized by complexity, plurality, and diversity, which seriously affects the quality of survival and prognosis of patients. Studies have focused on and recognized neurotransmitter-based mechanisms and selective serotonin-reuptake inhibitors (SSRIs) can be used to treat PSD. Neuroinflammation, neuroendocrinology, neurotrophic factors, and the site of the stroke lesion may affect neurotransmitters. Thus the mechanisms of PSD have been increasingly studied. Pharmacological treatment mainly includes SSRIs, noradrenergic and specific serotonergic antidepressant (NaSSA), anti-inflammatory drugs, vitamin D, ect, which have been confirmed to have better efficacy by clinical studies. Currently, there is an increasing number of studies related to the mechanisms of PSD. However, the mechanisms and pharmacologic treatment of PSD is still unclear. In the future, in-depth research on the mechanisms and treatment of PSD is needed to provide a reference for the prevention and treatment of clinical PSD.

A systematic review of the cell death mechanisms in retinal pigment epithelium cells and photoreceptors after subretinal hemorrhage - Implications for treatment options

Humans rely on vision as their most important sense. This is accomplished by photoreceptors (PRs) in the retina that detect light but cannot function without the support and maintenance of the retinal pigment epithelium (RPE). In subretinal hemorrhage (SRH), blood accumulates between the neurosensory retina and the RPE or between the RPE and the choroid. Blood breakdown products subsequently damage PRs and the RPE and lead to poor vision and blindness. Hence, there is a high need for options to preserve the retina and visual functions. We conducted a systematic review of the literature in accordance with the PRISMA guidelines to identify the cell death mechanisms in RPE and PRs after SRH to deepen our understanding of the pathways involved. After screening 736 publications published until November 8, 2022, we identified 19 records that assessed cell death in PRs and/or RPE in experimental models of SRH. Among the different cell death mechanisms, apoptosis was the most widely investigated mechanism (11 records), followed by ferroptosis (4), whereas necroptosis, pyroptosis, and lysosome-dependent cell death were only assessed in one study each. We discuss different therapeutic options that were assessed in these studies, including the removal of the hematoma/iron chelation, cytoprotection, anti-inflammatory agents, and antioxidants. Further systematic investigations will be necessary to determine the exact cell death mechanisms after SRH with respect to different blood breakdown components, cell types, and time courses. This will form the basis for the development of novel treatment options for SRH.

Brain organoids for hypoxic-ischemic studies: from bench to bedside

Our current knowledge regarding the development of the human brain mostly derives from experimental studies on non-human primates, sheep, and rodents. However, these studies may not completely simulate all the features of human brain development as a result of species differences and variations in pre- and postnatal brain maturation. Therefore, it is important to supplement the in vivo animal models to increase the possibility that preclinical studies have appropriate relevance for potential future human trials. Three-dimensional brain organoid culture technology could complement in vivo animal studies to enhance the translatability of the preclinical animal studies and the understanding of brain-related disorders. In this review, we focus on the development of a model of hypoxic-ischemic (HI) brain injury using human brain organoids to complement the translation from animal experiments to human pathophysiology. We also discuss how the development of these tools provides potential opportunities to study fundamental aspects of the pathophysiology of HI-related brain injury including differences in the responses between males and females.

Treating Traumatic Brain Injury with Minocycline

Traumatic brain injury (TBI) results in both rapid and delayed brain damage. The speed, complexity, and persistence of TBI present large obstacles to drug development. Preclinical studies from multiple laboratories have tested the FDA-approved anti-microbial drug minocycline (MINO) to treat traumatic brain injury. At concentrations greater than needed for anti-microbial action, MINO readily inhibits microglial activation. MINO has additional pleotropic effects including anti-inflammatory, anti-oxidant, and anti-apoptotic activities. MINO inhibits multiple proteins that promote brain injury including metalloproteases, caspases, calpain, and polyADP-ribose-polymerase-1. At these elevated doses, MINO is well tolerated and enters the brain even when the blood-brain barrier is intact. Most preclinical studies with a first dose of MINO at less than 1 h after injury have shown improved multiple outcomes after TBI. Fewer studies with more delayed dosing have yielded similar results. A small number of clinical trials for TBI have established the safety of MINO and suggested some drug efficacy. Studies are also ongoing that either improve MINO pharmacology or combine MINO with other drugs to increase its therapeutic efficacy against TBI. This review builds upon a previous, recent review by some of the authors (Lawless and Bergold, Neural Regen Res 17:2589-92, 2022). The present review includes the additional preclinical studies examining the efficacy of minocycline in preclinical TBI models. This review also includes recommendations for a clinical trial to test MINO to treat TBI.

Novel therapeutic approaches to target neurodegeneration

Ageing is the main risk factor common to most primary neurodegenerative disorders. Indeed, age-related brain alterations have been long considered to predispose to neurodegeneration. Although protein misfolding and the accumulation of toxic protein aggregates have been considered as causative events in neurodegeneration, several other biological pathways affected by brain ageing also contribute to pathogenesis. Here, we discuss the evidence showing the involvement of the mechanisms controlling neuronal structure, gene expression, autophagy, cell metabolism and neuroinflammation in the onset and progression of neurodegenerative disorders. Furthermore, we review the therapeutic strategies currently under development or as future approaches designed to normalize these pathways, which may then increase brain resilience to cope with toxic protein species. In addition to therapies targeting the insoluble protein aggregates specifically associated with each neurodegenerative disorder, these novel pharmacological approaches may be part of combined therapies designed to rescue brain function.

Minocycline protects against microgliopathy in a Csf1r haplo-insufficient mouse model of adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP)

BACKGROUND

Mutations in colony-stimulating factor 1 receptor (CSF1R) are known to cause adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP), which has been recently demonstrated as a primary microgliopathy characterized by cognitive impairment. Although the molecular mechanism underlying CSF1R-mediated microgliopathy remains unclear, therapeutic strategies have generally targeted modulation of microglial function. In particular, the microglial inhibitor, minocycline, has been shown to attenuate learning and memory deficits in several neurodegenerative diseases. The objectives of this study were to investigate the pathogenic mechanisms underlying ALSP and to explore the therapeutic effects of minocycline in an in vivo model of ALSP. We hypothesized that inhibiting microglial activation via minocycline could reverse the behavior and pathological defects in ALSP model mice.

METHODS

We generated a Csf1r haploinsufficiency mouse model of ALSP using CRISPR/Cas9 genome editing and conducted electrophysiological recordings of long-term potentiation (LTP) and behavioral tests to validate the recapitulation of clinical ALSP characteristics in 8- to 11-month-old mice. RNA-sequencing was used to explore enriched gene expression in the molecular pathogenesis of ALSP. Microglial activation was assessed by immunofluorescent detection of Iba1 and CD68 in brain sections of male ALSP mice and pro-inflammatory activation and phagocytosis were assessed in Csf1r^+/- microglia. Therapeutic effects were assessed by behavioral tests, histological analysis, and morphological examination after four weeks of intraperitoneal injection with minocycline or vehicle control in Csf1r^+/- mice and wild-type control littermates.

RESULTS

We found that synaptic function was reduced in LTP recordings of neurons in the hippocampal CA1 region, while behavioral tests showed impaired spatial and cognitive memory specifically in male Csf1r^+/- mice. Increased activation, pro-inflammatory cytokine production, and enhanced phagocytic capacity were also observed in Csf1r^+/- microglia. Treatment with minocycline could suppress the activation of Csf1r^+/- microglia both in vitro and in vivo. Notably, the behavioral and pathological deficits in Csf1r^+/- mice were partially rescued by minocycline administration, potentially due to inhibition of microglial inflammation and phagocytosis in Csf1r^+/- mice.

CONCLUSIONS

Our study shows that CSF1R deficiency results in aberrant microglial activation, characterized by a pro-inflammatory phenotype and enhanced phagocytosis of myelin. Our results also indicate that microglial inhibition by minocycline can ameliorate behavioral impairment and ALSP pathogenesis in CSF1R-deficient male mice, suggesting a potential therapeutic target for CSF1R-related leukoencephalopathy. Collectively, these data support that minocycline confers protective effects against CSF1R-related microgliopathy in male ALSP model mice.

The medicinal chemistry of Urtica dioica L.: from preliminary evidence to clinical studies supporting its neuroprotective activity

Urtica dioica is a perennial herb from the family of Urticaceae that is commonly known as stinging nettle. This plant is widespread in Europe, Africa, America, and a part of Asia, as it adapts to different environments and climatic conditions. The leaves, stalk, and bark of U. dioica found applications in the field of nutrition, cosmetics, textile, pest control and pharmacology. In this connection, bioactive chemical constituents such as flavonoids, phenolic acids, amino acids, carotenoids, and fatty acids have been isolated from the plant. With this review, we aim at providing an updated and comprehensive overview of the contributions in literature reporting computational, in vitro, pre-clinical and clinical data supporting the therapeutic applications of U. dioica. Experimental evidence shows that U. dioica constituents and extracts can provide neuroprotective effects by acting through a combination of different molecular mechanisms, that are discussed in the review. These findings could lay the basis for the identification and design of more effective tools against neurodegenerative diseases.

Minocycline alleviated scopolamine-induced amnesia by regulating antioxidant and cholinergic function

Background and aim

Minocycline, a tetracycline derivative, has been found to exert neuroprotective properties. The current project aimed to assess the antioxidant status and cholinergic function in the amnesia induced by scopolamine.

Methods

We evaluated the passive avoidance performance, acetylcholine esterase (AChE) enzyme activity, and the oxidative stress indicators in the following groups: Normal control, scopolamine, and the treatment groups (the animals were given minocycline (10-30 mg/kg)).

Results

Scopolamine (intraperitoneal) injection was associated with impairment of passive avoidance performance and neurotoxicity. Minocycline pronouncedly ameliorated scopolamine injury as presented by the increased latency time to darkness and stay time in lightness along with the decreased darkness entry. Moreover, minocycline decreased lipid peroxidation, while it elevated the levels of superoxide dismutase, AChE enzymes, and thiol groups in both the cortex and hippocampus.

Conclusion

Our data suggested that minocycline modulated the antioxidant status and AChE in the brains, which may contribute to its protective effects against scopolamine-induced amnesia.

Breaking down the cellular responses to type I interferon neurotoxicity in the brain

Since their original discovery, type I interferons (IFN-Is) have been closely associated with antiviral immune responses. However, their biological functions go far beyond this role, with balanced IFN-I activity being critical to maintain cellular and tissue homeostasis. Recent findings have uncovered a darker side of IFN-Is whereby chronically elevated levels induce devastating neuroinflammatory and neurodegenerative pathologies. The underlying causes of these 'interferonopathies' are diverse and include monogenetic syndromes, autoimmune disorders, as well as chronic infections. The prominent involvement of the CNS in these disorders indicates a particular susceptibility of brain cells to IFN-I toxicity. Here we will discuss the current knowledge of how IFN-Is mediate neurotoxicity in the brain by analyzing the cell-type specific responses to IFN-Is in the CNS, and secondly, by exploring the spectrum of neurological disorders arising from increased IFN-Is. Understanding the nature of IFN-I neurotoxicity is a crucial and fundamental step towards development of new therapeutic strategies for interferonopathies.

Anti-Inflammatory Therapy as a Promising Target in Neuropsychiatric Disorders

This chapter analyzes the therapeutic potential of current anti-inflammatory drugs in treating psychiatric diseases from a neuro-immunological perspective. Based on the bidirectional brain-immune system relationship, the rationale is that a dysregulated inflammation contributes to the pathogenesis of psychiatric and neurological disorders, while the immunology function is associated with psychological variables like stress, affective disorders, and psychosis. Under certain social, psychological, and environmental conditions and biological factors, a healthy inflammatory response and the associated "sickness behavior," which are aimed to resolve a physical injury and microbial threat, become harmful to the central nervous system. The features and mechanisms of the inflammatory response are described across the main mental illnesses with a special emphasis on the profile of cytokines and the function of the HPA axis. Next, it is reviewed the potential clinical utility of immunotherapy (cytokine agonists and antagonists), glucocorticoids, unconventional anti-inflammatory agents (statins, minocycline, statins, and polyunsaturated fatty acids (PUFAs)), the nonsteroidal anti-inflammatory drugs (NSAIDs), and particularly celecoxib, a selective cyclooxygenase-2 (Cox-2) inhibitor, as adjuvants of conventional psychiatric medications. The implementation of anti-inflammatory therapies holds great promise in psychiatry. Because the inflammatory background may account for the etiology and/or progression of psychiatric disorders only in a subset of patients, there is a need to elucidate the immune underpinnings of the mental illness progression, relapse, and remission. The identification of immune-related bio-signatures will ideally assist in the stratification of the psychiatric patient to predict the risk of mental disease, the prognosis, and the response to anti-inflammatory therapy.

New insight in the cross-talk between microglia and schizophrenia: From the perspective of neurodevelopment

Characterized by psychotic symptoms, negative symptoms and cognitive deficits, schizophrenia had a catastrophic effect on patients and their families. Multifaceted reliable evidence indicated that schizophrenia is a neurodevelopmental disorder. Microglia, the immune cells in central nervous system, related to many neurodevelopmental diseases. Microglia could affect neuronal survival, neuronal death and synaptic plasticity during neurodevelopment. Anomalous microglia during neurodevelopment may be associated with schizophrenia. Therefore, a hypothesis proposes that the abnormal function of microglia leads to the occurrence of schizophrenia. Nowadays, accumulating experiments between microglia and schizophrenia could afford unparalleled probability to assess this hypothesis. Herein, this review summarizes the latest supporting evidence in order to shed light on the mystery of microglia in schizophrenia.

Minocycline Protects Against Lipopolysaccharide-Induced Cognitive Impairment and Oxidative Stress: Possible Role of the CREB-BDNF Signaling Pathway

The oxidative stress-induced dysregulation of the cyclic AMP response element-binding protein- brain-derived neurotrophic factor (CREB-BDNF) cascade has been linked to cognitive impairment in several studies. This study aimed to investigate the effect of minocycline on the levels of oxidative stress markers, CREB, and BDNF in lipopolysaccharide (LPS)-induced cognitive impairment. Fifty adult male Sprague Dawley rats were divided randomly into five groups. Group 1 was an untreated control group. Groups 2, 3, 4 and 5 were treated concurrently with LPS (5 mg/kg, i.p) once on day 5 and normal saline (0.7 ml/rat, i.p) or minocycline (25 and 50 mg/kg, i.p) or memantine (10 mg/kg, i.p) once daily from day 1 until day 14, respectively. From day 15 to day 22 of the experiment, Morris Water Maze (MWM) was used to evaluate learning and reference memory in rats. The levels of protein carbonyl (PCO), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD) were determined by enzyme-linked immunosorbent assay (ELISA). CREB and BDNF expression and density were measured by immunohistochemistry and western blot analysis, respectively. LPS administration significantly increased escape latency to the hidden platform with decreased travelled distance, swimming speed, target crossings and time spent in the target quadrant. Besides, the hippocampal tissue of LPS rats showed increased levels of PCO and MDA, decreased levels of CAT and SOD, and reduced expression and density of BDNF and CREB. Treatment with minocycline reversed these effects in a dose-dependent manner, comparable to the effects of memantine. Both doses of minocycline treatment protect against LPS-induced cognitive impairment by reducing oxidative stress and upregulating the CREB-BDNF signalling pathway in the rat hippocampus.

Antibiotics and mental health: The good, the bad and the ugly

Antibiotics are recognised as, on occasion, producing psychiatric side effects, most notably depression and anxiety. Apart from antimicrobial activity, antibiotics have multiple off-target effects. The brain-gut-microbiota axis has multiple sites for off-target activity, which may produce either positive or negative antibiotic effects. Here we review how antibiotics impact mental health by acting through the brain-gut-microbiota axis. Microbes in the gut influence brain function by acting through the vagus nerve or by altering the production of short-chain fatty acids or the amino acid tryptophan, the building block of serotonin. Not all antimicrobial actions of antibiotics have a negative impact. The first antidepressant discovered was actually an antibiotic: isoniazid is an antibacterial drug developed for treating tuberculosis. Minocycline, which enters the brain and mediates its effects through microglia, shows antidepressant activity. Some antibiotics bring about a significant decrease in gut microbial diversity, and this is viewed as a risk factor for depression. Other risk factors induced by antibiotics include altered gut barrier function, activation of the hypothalamic-pituitary-adrenal axis, reducing levels of brain-derived neurotrophic factor or oxytocin and alteration of vagal tone. Although most patients taking antibiotics do not suffer from an iatrogenic psychiatric disorder, some do. As clinicians, we need to keep this in mind. The development of new antibiotics is primarily focused on antibiotic resistance, but efforts should be made to reduce off-target brain-gut-microbiota effects resulting in mental health problems.

Effect of regulating macrophage polarization phenotype on intervertebral disc degeneration

Background

Macrophages are the only inflammatory cells that can penetrate the closed nucleus pulposus and their polarization plays an important role in intervertebral disc degeneration (IVDD). This paper attempted to investigate the pathogenesis of IVDD by altering the polarization state of macrophages.

Methods

Macrophage RAW264.7 cells were induced by interferonγ (IFN‐γ) and lipopolysaccharide (LPS). The polarization of RAW264.7 cells was estimated by western blot and immunofluorescence. The expressions of inflammatory factors were detected by ELISA. Subsequently, RAW264.7 cells were treated with different concentrations of minocycline (Mino) and sinomenine (Sino), followed by the assessment of cell viability with cell counting kit‐8 kit. Then, RAW264.7 cell culture medium was collected for the culture of human nucleus pulposus cells (NPCs). Toluidine blue staining and type II collagen staining were applied to assay the level of type II collagen. The cell apoptosis, oxidative stress, and nitric oxide (NO) level were appraised by TUNEL, oxidative stress kits and NO kit, respectively. Western blot was employed to test the levels of apoptosis‐ and oxidative stress‐related proteins.

Results

IFN‐γ and LPS could induce M1 polarization of RAW264.7 cells. Mino and Sino could reduce the polarization of RAW264.7 cells toward M1. M1‐polarized medium inhibited LPS‐induced activity, inflammation, and damage of NPCs, which were enhanced by Mino and Sino in medium.

Conclusion

M1 polarization of macrophages promoted LPS‐induced inflammation and damage of NPCs.

The dual function of microglial polarization and its treatment targets in ischemic stroke

Stroke is the leading cause of disability and death worldwide, with ischemic stroke occurring in ~5% of the global population every year. Recently, many studies have been conducted on the inflammatory response after stroke. Microglial/macrophage polarization has a dual function and is critical to the pathology of ischemic stroke. Microglial/macrophage activation is important in reducing neuronal apoptosis, enhancing neurogenesis, and promoting functional recovery after ischemic stroke. In this review, we investigate the physiological characteristics and functions of microglia in the brain, the activation and phenotypic polarization of microglia and macrophages after stroke, the signaling mechanisms of polarization states, and the contribution of microglia to brain pathology and repair. We summarize recent advances in stroke-related microglia research, highlighting breakthroughs in therapeutic strategies for microglial responses after stroke, thereby providing new ideas for the treatment of ischemic stroke.

Minocycline attenuates cholinergic dysfunction and neuro-inflammation-mediated cognitive impairment in scopolamine-induced Alzheimer's rat model

OBJECTIVE

Minocycline, a semisynthetic tetracycline-derived antibiotic, has various pharmacological effect such as anti-inflammatory, anti-oxidative stress, and anti-apoptotic effects. The current study investigated the involvement of neuro-inflammatory, oxidative stress, and cholinergic markers in neuroprotection by minocycline against scopolamine-induced brain damage.

METHODS

Minocycline was administered (oral, 10, 15, and 30 mg/kg, daily) to groups of amnesic rats for 21 days. Passive avoidance memory and spatial learning and memory were assessed. Following that, oxidative stress, cholinergic function, and neuro-inflammation markers were evaluated in the brain tissue.

RESULTS

According to our biochemical data, treatment of the scopolamine-injured rats with minocycline decreased the levels of malondialdehyde and acetylcholinesterase (AChE) as well as mRNA expression of AChE and neuro-inflammation markers (tumor necrosis factor-α, interleukin (IL)-1β, IL-6). It also increased the total thiol levels and superoxide dismutase activity as well as mRNA expression of cholinergic receptor M1 (ChRM1). Moreover, minocycline modified distance and latencies in Morris water maze, prolonged latency to enter the black zone and light time while decreasing time spent and frequency of entries to darkness.

CONCLUSION

Taken together, the data indicate that treatment with minocycline improved memory dysfunction mediated possibly through restoring AChE and ChRM1 levels, oxidant/antioxidant balance, as well as inhibiting inflammatory responses.

Neighborhood-based inference and restricted Boltzmann machine for microbe and drug associations prediction

Background

Efficient identification of microbe-drug associations is critical for drug development and solving problem of antimicrobial resistance. Traditional wet-lab method requires a lot of money and labor in identifying potential microbe-drug associations. With development of machine learning and publication of large amounts of biological data, computational methods become feasible.

Methods

In this article, we proposed a computational model of neighborhood-based inference (NI) and restricted Boltzmann machine (RBM) to predict potential microbe-drug association (NIRBMMDA) by using integrated microbe similarity, integrated drug similarity and known microbe-drug associations. First, NI was used to obtain a score matrix of potential microbe-drug associations by using different thresholds to find similar neighbors for drug or microbe. Second, RBM was employed to obtain another score matrix of potential microbe-drug associations based on contrastive divergence algorithm and sigmoid function. Because generalization ability of individual method is poor, we used an ensemble learning to integrate two score matrices for predicting potential microbe-drug associations more accurately. In particular, NI can fully utilize similar (neighbor) information of drug or microbe and RBM can learn potential probability distribution hid in known microbe-drug associations. Moreover, ensemble learning was used to integrate individual predictor for obtaining a stronger predictor.

Results

In global leave-one-out cross validation (LOOCV), NIRBMMDA gained the area under the receiver operating characteristics curve (AUC) of 0.8666, 0.9413 and 0.9557 for datasets of DrugVirus, MDAD and aBiofilm, respectively. In local LOOCV, AUCs of 0.8512, 0.9204 and 0.9414 were obtained for NIRBMMDA based on datasets of DrugVirus, MDAD and aBiofilm, respectively. For five-fold cross validation, NIRBMMDA acquired AUC and standard deviation of 0.8569 ± -0.0027, 0.9248 ± -0.0014 and 0.9369 ± -0.0020 on the basis of datasets of DrugVirus, MDAD and aBiofilm, respectively. Moreover, case study for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) showed that 13 out of the top 20 predicted drugs were verified by searching literature. The other two case studies indicated that 17 and 17 out of the top 20 predicted microbes for the drug of ciprofloxacin and minocycline were confirmed by identifying published literature, respectively.

Hypothesized neuroprotective effect of minocycline against COVID-19-induced stroke and neurological dysfunction: possible role of matrix metalloprotease signaling pathway

Severe Acute Respiratory Syndrome Coronavirus-2 (COVID-19) is a respiratory disease that causes dysfunction in respiration. Since late 2019, this virus has infected and killed millions of people around the world and imposed many medical and therapeutic problems in the form of a pandemic. According to recent data, COVID-19 disease can increase the risk of stroke, which can be deadly or cause many neurological disorders after the disease. During the last two years, many efforts have been made to introduce new therapies for management of COVID-19-related complications, including stroke. To achieve this goal, several conventional drugs have been investigated for their possible therapeutic roles. Minocycline, a broad-spectrum, long-acting antibiotic with anti-inflammatory and antioxidant properties, is one such conventional drug that should be considered for treating COVID-19-related stroke, as indirect evidence indicates that it exerts neuroprotective effects, can modulate stroke occurrence, and can play an effective and strategic role in management of the molecular signals caused by stroke and its destructive consequences. The matrix metalloprotease (MMP) signaling pathway is one of the main signaling pathways involved in the occurrence and exacerbation of stroke; however, its role in COVID-19-induced stroke and the possible role of minocycline in the management of this signaling pathway in patients with COVID-19 is unclear and requires further investigation. Based on this concept, we hypothesize that minocycline might act via MMP signaling as a neuroprotective agent against COVID-19-induced neurological dysfunction, particularly stroke.

Insights into the roles of bacterial infection and antibiotics in Parkinson’s disease

Parkinson’s disease (PD) is one of the most common neurodegenerative disorders, which is accompanied with the classical motor symptoms and a range of non-motor symptoms. Bacterial infection affects the neuroinflammation associated with the pathology of PD and various antibiotics have also been confirmed to play an important role not only in bacterial infection, but also in the PD progression. This mini-review summarized the role of common bacterial infection in PD and introduced several antibiotics that had anti-PD effects.

Tetracyclines-An Important Therapeutic Tool for Dermatologists

Tetracyclines are a group of antibiotics whose first representative was discovered over 70 years ago. Since then, they have been of great interest in dermatology. In addition to their antibacterial activity, they are able to inhibit metalloproteinases and exhibit anti-inflammatory, anti-apoptotic and antioxidant effects. The side effects have been thoroughly studied over the years, the most characteristic and important ones in daily dermatological practice being: phototoxicity, hyperpigmentation, onycholysis, photoonycholysis, induced lupus erythematosus, and idiopathic intracranial hypertension. In this article, we summarize the use of tetracyclines in infectious diseases and inflammatory dermatoses, and further discuss the instances where the efficacy and safety of tetracyclines have been highlighted over the past few years.

Inherited Retinal Dystrophies: Role of Oxidative Stress and Inflammation in Their Physiopathology and Therapeutic Implications

Inherited retinal dystrophies (IRDs) are a large group of genetically and clinically heterogeneous diseases characterized by the progressive degeneration of the retina, ultimately leading to loss of visual function. Oxidative stress and inflammation play fundamental roles in the physiopathology of these diseases. Photoreceptor cell death induces an inflammatory state in the retina. The activation of several molecular pathways triggers different cellular responses to injury, including the activation of microglia to eliminate debris and recruit inflammatory cells from circulation. Therapeutical options for IRDs are currently limited, although a small number of patients have been successfully treated by gene therapy. Many other therapeutic strategies are being pursued to mitigate the deleterious effects of IRDs associated with oxidative metabolism and/or inflammation, including inhibiting reactive oxygen species’ accumulation and inflammatory responses, and blocking autophagy. Several compounds are being tested in clinical trials, generating great expectations for their implementation. The present review discusses the main death mechanisms that occur in IRDs and the latest therapies that are under investigation.

Blue Light Induces RPE Cell Necroptosis, Which Can Be Inhibited by Minocycline

Purpose:

Damage to and death of the retinal pigment epithelium (RPE) are closely related to retinal degeneration. Blue light is a high-energy light that causes RPE damage and triggers inflammatory responses. This study investigates whether blue light induces RPE necroptosis, explores pharmacologic therapy and specific mechanisms, and provides hints for research on retinal degeneration.

Methods

The human RPE cell line ARPE-19 was cultured and subjected to blue light insult in vitro. Annexin V/PI was used to evaluate RPE survival. Minocycline was applied to inhibit the death of RPE. Proteomic measurement was used to analyze protein expression. Inhibitors of necroptosis and apoptosis were applied to assess the death mode. Immunofluorescence of protein markers was detected to analyze the mechanism of cell death. Subcellular structural changes were detected by transmission electron microscopy. Reactive oxygen species (ROS) was tested by DCFH-DA. Mitochondrial membrane potential (Δψ_m) was detected by JC-1. BALB/c mice received bule light exposure, and RPE flatmounts were stained for verification in vivo.

Results

Blue light illumination induced RPE death, and minocycline significantly diminished RPE death. Proteomic measurement showed that minocycline effectively mitigated protein hydrolysis and protein synthesis disorders. Necroptosis inhibitors (Nec-1s, GSK-872) increased the survival of RPE cells, but apoptosis inhibitors (Z-VAD-FMK) did not. After blue light illumination, high-mobility group box-1 (HMGB1) was released from the nucleus, receptor-interacting protein kinase 3 (RIPK3) aggregated, and mixed-lineage kinase domain-like protein (MLKL) increased in the RPE. The application of minocycline alleviated the above phenomena. After blue light illumination, RPE cells exhibited necrotic characteristics accompanied by destruction of cell membranes and vacuole formation, but nuclear membranes remained intact. Minocycline improved the morphology of RPE. Blue light increased ROS and decreased Δψ_m of RPE, minocycline did not reduce ROS but kept Δψ_m stable. In vivo, HMGB1 release and RIPK3 aggregation appeared in the RPE of BALB/c mice after blue light illumination, and minocycline alleviated this effect.

Conclusions

Blue light exposure causes RPE necroptosis. Minocycline reduces the death of RPE by keeping Δψ_m stable, inhibiting necroptosis, and preventing HMGB1 release. These results provide new ideas for the pathogenesis and treatment of retinal degeneration.

Minocycline plus Zinc Oxide Eugenol Cement Might Be A Promising Alternative for Acute Pulpitis

Objective

To investigate the clinical effect of minocycline plus zinc oxide eugenol cement in the treatment of acute pulpitis and its effect on the levels of HIF-1α, Bcl-2, and tumor necrosis factor α.

Methods

A total of 286 patients with acute pulpitis who were treated in our hospital from January 2019 to October 2020 were recruited and assigned (1 : 1) via random number table method to receive either minocycline (control group) or minocycline plus zinc oxide eugenol cement (study group). Outcome measures included treatment effect, tooth mobility, tooth percussion pain score, hypoxia-inducible factor (HIF)-1α and B-lymphocyte tumor (Bcl)-2 positive rate, and tumor necrosis factor (TNF-α).

Results

Minocycline plus zinc oxide eugenol cement was associated with significantly lower scores of teeth mobility and percussion pain versus minocycline alone (p < 0.05). Minocycline plus zinc oxide eugenol cement resulted in a significantly higher treatment efficacy (97.20%) versus minocycline alone (72.73%) (p < 0.05). Minocycline plus zinc oxide eugenol cement was associated with significantly lower positive rates of HIF-1α and Bcl-2 and lower levels of TNF-α versus minocycline alone (p < 0.05). The patients receiving minocycline plus zinc oxide eugenol cement showed significantly lower visual analogue scale (VAS) scores and faster pain relief versus those given minocycline alone (p < 0.05).

Conclusion

Minocycline plus zinc oxide eugenol cement offers a viable alternative for acute pulpitis as it mitigates the pain of patients, alleviates inflammatory responses, and lowers the positive rate of HIF-1α and Bcl-2, so it is worthy of clinical promotion.

Neuroprotective Properties of Minocycline Against Methylphenidate-Induced Neurodegeneration: Possible Role of CREB/BDNF and Akt/GSK3 Signaling Pathways in Rat Hippocampus

Neurodegeneration is a side effect of methylphenidate (MPH), and minocycline possesses neuroprotective properties. This study aimed to investigate the neuroprotective effects of minocycline against methylphenidate-induced neurodegeneration mediated by signaling pathways of CREB/BDNF and Akt/GSK3. Seven groups of seventy male rats were randomly distributed in seven groups (n = 10). Group 1 received 0.7 ml/rat of normal saline (i.p.), and group 2 was treated with MPH (10 mg/kg, i.p.). Groups 3, 4, 5, and 6 were simultaneously administered MPH (10 mg/kg) and minocycline (10, 20, 30, and 40 mg/kg, i.p.) for 21 days. Minocycline alone (40 mg/kg, i.p.) was administrated to group 7. Open field test (OFT) (on day 22), forced swim test (FST) (on day 24), and elevated plus maze (on day 26) were conducted to analyze the mood-related behaviors; hippocampal oxidative stress, inflammatory, and apoptotic parameters, as well as the levels of protein kinase B (Akt-1), glycogen synthase kinase 3 (GSK3), cAMP response element-binding protein (CREB), and brain-derived neurotrophic factor (BDNF), were also assessed. Furthermore, localization of total CREB, Akt, and GSK3 in the DG and CA1 areas of the hippocampus were measured using immunohistochemistry (IHC). Histological changes in the mentioned areas were also evaluated. Minocycline treatment inhibited MPH-induced mood disorders and decreased lipid peroxidation, oxidized form of glutathione (GSSG), interleukin 1 beta (IL-1β), alpha tumor necrosis factor (TNF-α), Bax, and GSK3 levels. In the contrary, it increased the levels of reduced form of glutathione (GSH), Bcl-2, CREB, BDNF, and Akt-1 and superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) activities in the experimental animals' hippocampus. IHC data showed that minocycline also improved the localization and expression of CREB and Akt positive cells and decreased the GSK3 positive cells in the DG and CA1 regions of the hippocampus of MPH-treated rats. Minocycline also inhibited MPH-induced changes of hippocampal cells' density and shape in both DG and CA1 areas of the hippocampus. According to obtained data, it can be concluded that minocycline probably via activation of the P-CREB/BDNF or Akt/GSK3 signaling pathway can confer its neuroprotective effects against MPH-induced neurodegeneration.

Alzheimer’s Disease: An Update and Insights Into Pathophysiology

Alzheimer’s disease (AD) is an irreversible brain disorder associated with slow, progressive loss of brain functions mostly in older people. The disease processes start years before the symptoms are manifested at which point most therapies may not be as effective. In the hippocampus, the key proteins involved in the JAK2/STAT3 signaling pathway, such as p-JAK2-Tyr1007 and p-STAT3-Tyr705 were found to be elevated in various models of AD. In addition to neurons, glial cells such as astrocytes also play a crucial role in the progression of AD. Without having a significant effect on tau and amyloid pathologies, the JAK2/STAT3 pathway in reactive astrocytes exhibits a behavioral impact in the experimental models of AD. Cholinergic atrophy in AD has been traced to a trophic failure in the NGF metabolic pathway, which is essential for the survival and maintenance of basal forebrain cholinergic neurons (BFCN). In AD, there is an alteration in the conversion of the proNGF to mature NGF (mNGF), in addition to an increase in degradation of the biologically active mNGF. Thus, the application of exogenous mNGF in experimental studies was shown to improve the recovery of atrophic BFCN. Furthermore, it is now coming to light that the FGF7/FGFR2/PI3K/Akt signaling pathway mediated by microRNA-107 is also involved in AD pathogenesis. Vascular dysfunction has long been associated with cognitive decline and increased risk of AD. Vascular risk factors are associated with higher tau and cerebral beta-amyloid (Aβ) burden, while synergistically acting with Aβ to induce cognitive decline. The apolipoprotein E4 polymorphism is not just one of the vascular risk factors, but also the most prevalent genetic risk factor of AD. More recently, the research focus on AD shifted toward metabolisms of various neurotransmitters, major and minor nutrients, thus giving rise to metabolomics, the most important “omics” tool for the diagnosis and prognosis of neurodegenerative diseases based on an individual’s metabolome. This review will therefore proffer a better understanding of novel signaling pathways associated with neural and glial mechanisms involved in AD, elaborate potential links between vascular dysfunction and AD, and recent developments in “omics”-based biomarkers in AD.

Drug Repurposing to Target Neuroinflammation and Sensory Neuron-Dependent Pain

Around 20% of the American population have chronic pain and estimates in other Western countries report similar numbers. This represents a major challenge for global health care systems. Additional problems for the treatment of chronic and persistent pain are the comparably low efficacy of existing therapies, the failure to translate effects observed in preclinical pain models to human patients and related setbacks in clinical trials from previous attempts to develop novel analgesics. Drug repurposing offers an alternative approach to identify novel analgesics as it can bypass various steps of classical drug development. In recent years, several approved drugs were attributed analgesic properties. Here, we review available data and discuss recent findings suggesting that the approved drugs minocycline, fingolimod, pioglitazone, nilotinib, telmisartan, and others, which were originally developed for the treatment of different pathologies, can have analgesic, antihyperalgesic, or neuroprotective effects in preclinical and clinical models of inflammatory or neuropathic pain. For our analysis, we subdivide the drugs into substances that can target neuroinflammation or substances that can act on peripheral sensory neurons, and highlight the proposed mechanisms. Finally, we discuss the merits and challenges of drug repurposing for the development of novel analgesics.

Phosphorylation at Ser 727 Increases STAT3 Interaction with PKCε Regulating Neuron–Glia Crosstalk via IL-6-Mediated Hyperalgesia In Vivo and In Vitro

Methods

A rat hyperalgesia model was induced using an intraplantar injection of Freund's complete adjuvant (FCA) or an intrathecal injection of IL-6. Mechanical allodynia was evaluated using von Frey filament tests after intrathecal injections of T-5224 (c-Fos/AP-1 inhibitor), minocycline (Mino, a specific microglia inhibitor), L-2-aminoadipic acid (LAA, an astroglial toxin), PKCε inhibitor peptide, APTSTAT3-9R (STAT3 inhibitor), or anti-IL-6 antibody. The c-Fos, GFAP, Iba-1, PKCε, STAT3, pSTAT3^Tyr705 and pSTAT3^Ser727, and IL-6 expression at the spinal cord level was assessed by Western blot analysis. The interactive effects of PKCε and STAT3 were determined using immunofluorescence staining and immunoprecipitation in vivo and in vitro. Interleukin-6 promoter activity was examined using luciferase assays.

Results

T-5224, Mino, and LAA attenuated FCA- or IL-6-mediated inflammatory pain, with a decrease in c-Fos, GFAP, Iba-1, PKCε, and IL-6 expression. PKCε inhibitor peptide and APTSTAT3-9R reversed FCA-induced nociceptive behavior, while decreasing pSTAT3^Ser727, IL-6, c-Fos, GFAP, and Iba-1 expression and PKCε and STAT3 coexpression. Interleukin-6 promoter activity increased in the presence of PKCε and STAT3. The interaction with PKCε increased on phosphorylating STAT3 at Ser727 but not at Tyr705.

Conclusion

STAT3 phosphorylation at Ser 727 and the interaction with PKCε contribute to hyperalgesia via the IL-6-mediated signaling pathway, thus regulating neuron–glia crosstalk during inflammatory pain.

The Current Status of Neuroprotection in Congenital Heart Disease

Neurological deficits are a serious and common sequelae of congenital heart disease (CHD). While their underlying mechanisms have not been fully characterized, their manifestations are well-known and understood to persist through adulthood. Development of therapies to address or prevent these deficits are critical to attenuate future morbidity and improve quality of life. In this review, we aim to summarize the current status of neuroprotective therapy in CHD. Through an exploration of present research in the pre-operative, intra-operative, and post-operative phases of patient management, we will describe existing clinical and bench efforts as well as current endeavors underway within this research area.

Selected Molecular Targets for Antiepileptogenesis

The term epileptogenesis defines the usually durable process of converting normal brain into an epileptic one. The resistance of a significant proportion of patients with epilepsy to the available pharmacotherapy prompted the concept of a causative treatment option consisting in stopping or modifying the progress of epileptogenesis. Most antiepileptic drugs possess only a weak or no antiepileptogenic potential at all, but a few of them appear promising in this regard; these include, for example, eslicarbazepine (a sodium and T-type channel blocker), lamotrigine (a sodium channel blocker and glutamate antagonist) or levetiracetam (a ligand of synaptic vehicle protein SV2A). Among the approved non-antiepileptic drugs, antiepileptogenic potential seems to reside in losartan (a blocker of angiotensin II type 1 receptors), biperiden (an antiparkinsonian drug), nonsteroidal anti-inflammatory drugs, antioxidative drugs and minocycline (a second-generation tetracycline with anti-inflammatory and antioxidant properties). Among other possible antiepileptogenic compounds, antisense nucleotides have been considered, among these an antagomir targeting microRNA-134. The drugs and agents mentioned above have been evaluated in post-status epilepticus models of epileptogenesis, so their preventive efficacy must be verified. Limited clinical data indicate that biperiden in patients with brain injuries is well-tolerated and seems to reduce the incidence of post-traumatic epilepsy. Exceptionally, in this regard, our own original data presented here point to c-Fos as an early seizure duration, but not seizure intensity-related, marker of early epileptogenesis. Further research of reliable markers of early epileptogenesis is definitely needed to improve the process of designing adequate antiepileptogenic therapies.

A Characterization of the Effects of Minocycline Treatment During Adolescence on Structural, Metabolic, and Oxidative Stress Parameters in a Maternal Immune Stimulation Model of Neurodevelopmental Brain Disorders

BACKGROUND

Minocycline (MIN) is a tetracycline with antioxidant, anti-inflammatory, and neuroprotective properties. Given the likely involvement of inflammation and oxidative stress (IOS) in schizophrenia, MIN has been proposed as a potential adjuvant treatment in this pathology. We tested an early therapeutic window, during adolescence, as prevention of the schizophrenia-related deficits in the maternal immune stimulation (MIS) animal model.

METHODS

On gestational day 15, Poly I:C or vehicle was injected in pregnant Wistar rats. A total 93 male offspring received MIN (30 mg/kg) or saline from postnatal day (PND) 35-49. At PND70, rats were submitted to the prepulse inhibition test. FDG-PET and T2-weighted MRI brain studies were performed at adulthood. IOS markers were evaluated in frozen brain tissue.

RESULTS

MIN treatment did not prevent prepulse inhibition test behavioral deficits in MIS offspring. However, MIN prevented morphometric abnormalities in the third ventricle but not in the hippocampus. Additionally, MIN reduced brain metabolism in cerebellum and increased it in nucleus accumbens. Finally, MIN reduced the expression of iNOS (prefrontal cortex, caudate-putamen) and increased the levels of KEAP1 (prefrontal cortex), HO1 and NQO1 (amygdala, hippocampus), and HO1 (caudate-putamen).

CONCLUSIONS

MIN treatment during adolescence partially counteracts volumetric abnormalities and IOS deficits in the MIS model, likely via iNOS and Nrf2-ARE pathways, also increasing the expression of cytoprotective enzymes. However, MIN treatment during this peripubertal stage does not prevent sensorimotor gating deficits. Therefore, even though it does not prevent all the MIS-derived abnormalities evaluated, our results suggest the potential utility of early treatment with MIN in other schizophrenia domains.

Use of minocycline for the treatment of prurigo pigmentosa with intraepidermal vesiculation: a case report

Pruritus pigmentosa is a skin disease mainly characterized by pruritus, inflammatory rash and reticular and macular pigmentation. The disease more commonly affects young women and may persist for several years. In this article, we report a case of a 20-year-old female patient who presented with erythema and blisters on the neck and trunk with pruritus for 20 days. Dermatological examination revealed a reticular distribution of erythema on the chest and abdomen and some areas of erythema covered with crusts. Additionally, blisters and bullae with clear fluid and negative Nikolsky's sign were noted. On the neck and back, erythema was also in a reticular distribution, and erythema secondary to erosion and/or crusts was present. In addition, histopathological analysis of the lesions showed hyperkeratosis and intraepidermal multilocular vesiculation and confirmed increased migration of inflammatory cells into the epidermis and infiltration of inflammatory cells, including lymphocytes, histiocytes and eosinophils, in the superficial dermis. The expression levels of IgG, IgM, IgA and C3 were all negative. This patient was diagnosed with prurigo pigmentosa, and the condition improved after treatment with minocycline.