GM-CSF increases LPS-induced production of proinflammatory mediators via upregulation of TLR4 and CD14 in murine microglia

Crosstalk between CD64+MHCII+ macrophages and CD4+ T cells drives joint pathology during chikungunya

Communications between immune cells are essential to ensure appropriate coordination of their activities. Here, we observed the infiltration of activated macrophages into the joint-footpads of chikungunya virus (CHIKV)-infected animals. Large numbers of CD64+MHCII+ and CD64+MHCII- macrophages were present in the joint-footpad, preceded by the recruitment of their CD11b+Ly6C+ inflammatory monocyte precursors. Recruitment and differentiation of these myeloid subsets were dependent on CD4+ T cells and GM-CSF. Transcriptomic and gene ontology analyses of CD64+MHCII+ and CD64+MHCII- macrophages revealed 89 differentially expressed genes, including genes involved in T cell proliferation and differentiation pathways. Depletion of phagocytes, including CD64+MHCII+ macrophages, from CHIKV-infected mice reduced disease pathology, demonstrating that these cells play a pro-inflammatory role in CHIKV infection. Together, these results highlight the synergistic dynamics of immune cell crosstalk in driving CHIKV immunopathogenesis. This study provides new insights in the disease mechanism and offers opportunities for development of novel anti-CHIKV therapeutics.

Improvement of renal functions in mice with septic acute kidney injury using secretome of mesenchymal stem cells

Background

A potentially fatal complication of sepsis is septic acute kidney injury. Stem cell therapy is a potential new method of treating sepsis and has been applied to treat some human diseases.

Objectives

This study investigated the effects of secretome-MSCs on NGAL, CRP, NF-κB, and MMP-9 proteins, and histopathology in mice with septic AKI.

Methods

A post-test-only group design was conducted in 30 Balb/C male mice, which were randomly assigned to five groups: the control group was intraperitoneally injected with 0.5 ml of 0.9 % NaCl, the septic AKI, and the treatment groups (T1, T2, and T3) were intraperitoneally injected with 0.5 ml of 0.9 % NaCl and 0.3 mg/kg BW LPS single dose for three days. Three-day treatments of 150, 300, and 600 µl secretome-MSCs were administered intraperitoneally into the treatment groups. Furthermore, kidney and blood samples were collected for biochemical and histopathological analyses.

Results

The T1, T2, and T3 groups had lower expression of NF-κB and MMP-9 and significantly lower CRP and NGAL levels than that of septic AKI group. T1 (1.21 ± 0.19), T2 (0.75 ± 0.22), and T3 (0.38 ± 0.14) groups demonstrated lower average scores for inflammation, necrosis, hemorrhage, and degeneration compared to septic AKI group (2.17 ± 0.13).

Conclusions

Administration of 600 µl/20 g BW secretome-MSCs suppresses NF-κB and MMP-9 expression and reduces CRP and NGAL levels. Meanwhile, the 150 and 300 µl/20 g BW doses also indicated a greater improvement in renal tissue damage of mice with septic AKI.

Microbiomes in pancreatic cancer can be an accomplice or a weapon

Recently, several investigations have linked the microbiome to pancreatic cancer progression. It is critical to reveal the role of different microbiomes in the occurrence, development, and treatment of pancreatic cancer. The current review summarizes the various microbiota types in pancreatic cancer while updating and supplementing the mechanisms of the representative gut, pancreatic, and oral microbiota, and their metabolites during its pathogenesis and therapeutic intervention. Several novel strategies have been introduced based on the tumor-associated microbiome to optimize the early diagnosis and prognosis of pancreatic cancer. The pros and cons involving different microbiomes in treating pancreatic cancer are discussed. The microbiome-related clinical trials for pancreatic cancer theranostics are outlined. This convergence of cutting-edge knowledge will provide feasible ideas for developing innovative therapies against pancreatic cancer.

Granulocyte macrophage colony stimulating factor exerts dominant effects over macrophage colony stimulating factor during macrophage differentiation in vitro to induce an inflammatory phenotype

BACKGROUND

Macrophages (Mφ) can exist along a spectrum of phenotypes that include pro-inflammatory (M1) or anti-inflammatory (M2) immune cells. Mφ colony stimulating factor (M-CSF) and granulocyte Mφ colony stimulating factor (GM-CSF) are cytokines important in hematopoiesis, polarization and activation of Mφ.

METHODS AND RESULTS

To gain a greater understanding of the relationship between GM-CSF and M-CSF, we investigated an in vitro model of differentiation to determine if GM-CSF and M-CSF can antagonize each other, in terms of Mφ phenotype and functions. We determined that Mφ cultured in mixed M-CSF: GM-CSF ratios exhibit M1-like GM-CSF-treated macrophage phenotype when the ratios of the two cytokines are 1:1 in culture. Moreover, GM-CSF is dominant over M-CSF in influencing Mφ production of proinflammatory cytokines such as IL-6, TNFα, and IL-12p40, and the anti-inflammatory cytokine IL-10.

CONCLUSIONS

Our data established that GM-CSF is more dominant over M-CSF, triggering the Mφ to become pro-inflammatory cells. These findings provide insight into how GM-CSF can influence Mφ activation with implications in inflammatory diseases where the Mφ status can play a significant role in supporting the inflammatory conditions.

Enhancing Ocular Surface in Dry Eye Disease Patients: A Clinical Evaluation of a Topical Formulation Containing Sesquiterpene Lactone Helenalin

The aim of this work was to assess the tolerability, safety, and efficacy of an ophthalmic topical formulation containing helenalin from Arnica montana and hyaluronic acid 0.4% (HA) in patients with mild-to-moderate Dry Eye Disease (DED) exhibiting positive Matrix Metalloproteinase 9 (MMP-9) test results. Tolerability and safety were evaluated in 24 healthy subjects. Participants were instructed to apply one drop of the formulation three times a day in the study eye, for 2 weeks, followed by a clinical follow-up of 21 days. Efficacy was studied in 48 DED patients randomized into Study (Group 1/receiving the studied formulation) or Control (Group 2/Receiving HA 0.4% eye lubricant) groups for 1 month. Assessments included an MMP-9 positivity test, conjunctival impression cytology (CIC), Ocular Surface Disease Index (OSDI), non-invasive film tear breakup time (NIBUT), non-invasive average breakup time (NIAvg-BUT), ocular surface staining, Schirmer's test, and meibomiography. A crossover design with an additional 1-month follow-up was applied to both groups. Healthy subjects receiving the studied formulation exhibited good tolerability and no adverse events. Regarding the efficacy study, Group 1 exhibited a statistically significant reduction in the MMP-9 positivity rate compared to Group 2 (p < 0.001). Both Group 1 and Group 2 exhibited substantial improvements in OSDI and NIBUT scores (p < 0.001). However, Group 1 demonstrated a significant improvement in NI-Avg-BUT and Schirmer's test scores (p < 0.001), whereas Group 2 did not (p > 0.05). Finally, after the crossover, the proportion of MMP-9-positive subjects in Group 1 increased from 25% to 91.6%, while Group 2 showed a significant decrease from 87.5% to 20.8%. Overall, the topical formulation containing sesquiterpene helenalin from Arnica montana and hyaluronic acid was well tolerated and exhibited a favorable safety profile. Our formulation reduces DED symptomatology and modulates the ocular surface inflammatory process; this is evidenced by the enhancement of CIC, the improvement of DED-related tear film status, and the reduction of the MMP-9 positivity rate.

Mechanisms and structure-activity relationships of polysaccharides in the intervention of Alzheimer's disease: A review

Alzheimer's disease (AD) is a complex neurodegenerative disease. Despite several decades of research, the development of effective treatments and responses for Alzheimer's disease remains elusive. The utilization of polysaccharides for Alzheimer's disease became more popular due to their beneficial characteristics, notably their multi-target activity and low toxicity. This review mainly focuses on the researches of recent 5 years in the regulation of AD by naturally derived polysaccharides, systematically lists the possible intervention pathways of polysaccharides from different mechanisms, and explores the structure-activity relationship between polysaccharide structural activities, so as to provide references for the intervention and treatment of AD by polysaccharides.

An in vitro model for osteoarthritis using long-cultured inflammatory human macrophages repeatedly stimulated with TLR agonists

Osteoarthritis (OA) is characterized by an abundance of inflammatory M1-like macrophages damaging local tissues. The search for new potential drugs for OA suffers from the lack of appropriate methods of long-lasting inflammation. Here we developed and characterized an in vitro protocol of long-lasting culture of primary human monocyte-derived macrophages differentiated with a combination of M-CSF+GM-CSF that optimally supported long-cultured macrophages (LC-Mϕs) for up to 15 days, unlike their single use. Macrophages repeatedly stimulated for 15 days with the TLR2 ligand Pam3CSK4 (LCS-Mϕs), showed sustained levels over time of IL-6, CCL2, and CXCL8, inflammatory mediators that were also detected in the synovial fluids of OA patients. Furthermore, macrophages isolated from the synovia of two OA patients showed an expression profile of inflammation-related genes similar to that of LCS-Mϕs, validating our protocol as a model of chronically activated inflammatory macrophages. Next, to confirm that these LCS-Mϕs could be modulated by anti-inflammatory compounds, we employed dexamethasone and/or celecoxib, two drugs widely used in OA treatment, that significantly inhibited the production of inflammatory mediators. This easy-to-use in vitro protocol of long-lasting inflammation with primary human macrophages could be useful for the screening of new compounds to improve the therapy of inflammatory disorders.

Anti-Neuroinflammatory Effect of the Ethanolic Extract of Black Ginseng through TLR4-MyD88-Regulated Inhibition of NF-κB and MAPK Signaling Pathways in LPS-Induced BV2 Microglial Cells

Korean ginseng (Panax ginseng) contains various ginsenosides as active ingredients, and they show diverse biological activities. Black ginseng is manufactured by repeated steaming and drying of white ginseng, which alters the polarity of ginsenosides and improves biological activities. The aim of the present investigation was to examine the anti-neuroinflammatory effects of the ethanolic extract of black ginseng (BGE) in lipopolysaccharide (LPS)-induced BV2 microglial cells. Pre-treatment with BGE inhibited the overproduction of pro-inflammatory mediators including nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in LPS-induced BV2 cells. In addition, BGE reduced the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), p38 mitogen-activated protein kinase (MAPK), and c-jun N-terminal kinase (JNK) MAPK signaling pathways induced by LPS. These anti-neuroinflammatory effects were mediated through the negative regulation of the toll-like receptor 4 (TLR4)/myeloid differentiation primary response 88 (MyD88) signaling pathway. Among the four ginsenosides contained in BGE, ginsenosides Rd and Rg3 inhibited the production of inflammatory mediators. Taken together, this investigation suggests that BGE represents potential anti-neuroinflammatory candidates for the prevention and treatment of neurodegenerative diseases.

Emerging aspects of cytokine storm in COVID-19: The role of proinflammatory cytokines and therapeutic prospects

COVID-19 has claimed millions of lives during the last 3 years since initial cases were reported in Wuhan, China, in 2019. Patients with COVID-19 suffer from severe pneumonia, high fever, acute respiratory distress syndrome (ARDS), and multiple-organ dysfunction, which may also result in fatality in extreme cases. Cytokine storm (CS) is hyperactivation of the immune system, wherein the dysregulated production of proinflammatory cytokines could result in excessive immune cell infiltrations in the pulmonary tissues, resulting in tissue damage. The immune cell infiltration could also occur in other tissues and organs and result in multiple organs' dysfunction. The key cytokines implicated in the onset of disease severity include TNF-α, IFN-γ, IL-6, IL-1β, GM-CSF, and G-CSF. Controlling the CS is critical in treating COVID-19 disease. Therefore, different strategies are employed to mitigate the effects of CS. These include using monoclonal antibodies directed against soluble cytokines or the cytokine receptors, combination therapies, mesenchymal stem cell therapy, therapeutic plasma exchange, and some non-conventional treatment methods to improve patient immunity. The current review describes the role/s of critical cytokines in COVID-19-mediated CS and the respective treatment modalities.

TNFα induces matrix metalloproteinase-9 expression in monocytic cells through ACSL1/JNK/ERK/NF-kB signaling pathways

Studies have established the association between increased plasma levels of matrix metalloproteinase (MMP)-9 and adipose tissue inflammation. Tumor necrosis factor α (TNFα) was elevated in obesity and is involved in the induction of MMP-9 in monocytic cells. However, the underlying molecular mechanism was incompletely understood. As per our recent report, TNFα mediates inflammatory responses through long-chain acyl-CoA synthetase 1 (ACSL1). Therefore, we further investigated the role of ACSL1 in TNFα-mediated MMP-9 secretion in monocytic cells. THP-1 cells and primary monocytes were used to study MMP-9 expression. mRNA and protein levels of MMP-9 were determined by qRT-PCR and ELISA, respectively. Signaling pathways were studied using Western blotting, inhibitors, and NF-kB/AP1 reporter cells. We found that THP-1 cells and primary human monocytes displayed increased MMP-9 mRNA expression and protein secretion after incubation with TNFα. ACSL1 inhibition using triacsin C significantly reduced the expression of MMP-9 in the THP-1 cells. However, the inhibition of β-oxidation and ceramide biosynthesis did not affect the TNFα-induced MMP-9 production. Using small interfering RNA-mediated ACSL1 knockdown, we further confirmed that TNFα-induced MMP-9 expression/secretion was significantly reduced in ACSL1-deficient cells. TNFα-mediated MMP-9 expression was also significantly reduced by the inhibition of ERK1/ERK2, JNK, and NF-kB. We further observed that TNFα induced phosphorylation of SAPK/JNK (p54/46), ERK1/2 (p44/42 MAPK), and NF-kB p65. ACSL1 inhibition reduced the TNFα-mediated phosphorylation of SAPK/JNK, c-Jun, ERK1/2, and NF-kB. In addition, increased NF-κB/AP-1 activity was inhibited in triacsin C treated cells. Altogether, our findings suggest that ACSL1/JNK/ERK/NF-kB axis plays an important role in the regulation of MMP-9 induced by TNFα in monocytic THP-1 cells.

Treatment with Granulocyte-Macrophage Colony-Stimulating Factor Reduces Viral Titers in the Brains of West Nile Virus-Infected Mice and Improves Survival

West Nile virus (WNV) is the leading cause of epidemic arboviral encephalitis in the United States. As there are currently no proven antiviral therapies or licensed human vaccines, understanding the neuropathogenesis of WNV is critical for rational therapeutic design. In WNV-infected mice, the depletion of microglia leads to enhanced viral replication, increased central nervous system (CNS) tissue injury, and increased mortality, suggesting that microglia play a critical role in protection against WNV neuroinvasive disease. To determine if augmenting microglial activation would provide a potential therapeutic strategy, we administered granulocyte-macrophage colony-stimulating factor (GM-CSF) to WNV-infected mice. Recombinant human GM-CSF (rHuGMCSF) (sargramostim [Leukine]) is an FDA-approved drug used to increase white blood cells following leukopenia-inducing chemotherapy or bone marrow transplantation. Daily treatment of both uninfected and WNV-infected mice with subcutaneous injections of GM-CSF resulted in microglial proliferation and activation as indicated by the enhanced expression of the microglia activation marker ionized calcium binding adaptor molecule 1 (Iba1) and several microglia-associated inflammatory cytokines, including CCL2 (C-C motif chemokine ligand 2), interleukin 6 (IL-6), and IL-10. In addition, more microglia adopted an activated morphology as demonstrated by increased sizes and more pronounced processes. GM-CSF-induced microglial activation in WNV-infected mice was associated with reduced viral titers and apoptotic activity (caspase 3) in the brains of WNV-infected mice and significantly increased survival. WNV-infected ex vivo brain slice cultures (BSCs) treated with GM-CSF also showed reduced viral titers and caspase 3 apoptotic cell death, indicating that GM-CSF specifically targets the CNS and that its actions are not dependent on peripheral immune activity. Our studies suggest that stimulation of microglial activation may be a viable therapeutic approach for the treatment of WNV neuroinvasive disease. IMPORTANCE Although rare, WNV encephalitis poses a devastating health concern, with few treatment options and frequent long-term neurological sequelae. Currently, there are no human vaccines or specific antivirals against WNV infections, so further research into potential new therapeutic agents is critical. This study presents a novel treatment option for WNV infections using GM-CSF and lays the foundation for further studies into the use of GM-CSF as a treatment for WNV encephalitis as well as a potential treatment for other viral infections.

Dietary Protection against Cognitive Impairment, Neuroinflammation and Oxidative Stress in Alzheimer's Disease Animal Models of Lipopolysaccharide-Induced Inflammation

Alzheimer's disease (AD) is a rapidly growing epidemic with a heavy social and economic burden. Evidence suggests that systemic inflammation, dysregulation of the immune response and the resulting neuroinflammation and neurodegeneration play a significant role in AD pathogenesis. Currently, given that there is no fully convincing cure for AD, the interest in lifestyle factors (such as diet), which potentially delay onset and reduce the severity of symptoms, is increasing. This review is aimed at summarizing the effects of dietary supplementation on cognitive decline, neuroinflammation and oxidative stress in AD-like animal models with a focus on neuroinflammation induced by lipopolysaccharide (LPS) injection, which mimics systemic inflammation in animals. The compounds reviewed include curcumin, krill oil, chicoric acid, plasmalogens, lycopene, tryptophan-related dipeptides, hesperetin and selenium peptides. Despite the heterogeneity of these compounds, there is a strong consensus on their counteracting action on LPS-induced cognitive deficits and neuroinflammatory responses in rodents by modulating cell-signaling processes, such as the NF-κB pathway. Overall, dietary interventions could represent an important resource to oppose AD due to their influence in neuroprotection and immune regulation.

Neuroprotective effects of sesamol against LPS-induced spatial learning and memory deficits are mediated via anti-inflammatory and antioxidant activities in the rat brain

Objective

Sesamol is a phenolic lignan extracted from sesame seeds, and it possesses anti-inflammatory and antioxidant activities. Lipopolysaccharide (LPS) is known to produce neuroinflammatory responses and memory impairment. The current study aimed to investigate the protective influence of sesamol against LPS-mediated neuroinflammation and memory impairment.

Materials and Methods

Sesamol (10 and 50 mg/kg) was injected to Wistar rats for two weeks. Then, animals received LPS injection (1 mg/kg) for five days, while treatment with sesamol was performed 30 min before LPS injection. Spatial learning and memory were assessed by the Morris water maze (MWM), two hours after LPS injection on days 15-19. Biochemical assessments were performed after the end of behavioral experiments.

Results

LPS-administered rats showed spatial learning and memory deficits, since they spent more time in the MWM to find the hidden platform and less time in the target quadrant. Besides these behavioral changes, tumor necrosis factor-α (TNF-α) and lipid peroxidation levels were increased, while total thiol level was decreased in the hippocampus and/or cerebral cortex. In addition, sesamol treatment (50 mg/kg) for three weeks decreased the escape latency and increased the time on probe trial. Sesamol also reduced lipid peroxidation and TNF-α level, while enhanced total thiol level in the brain of LPS-exposed rats.

Conclusion

Supplementation of sesamol attenuated learning and memory impairments in LPS-treated rats via antioxidative and anti-inflammatory activities in the rat brain.

Mitogen-activated protein kinase inhibitor PD98059 improves neuroimmune dysfunction in experimental autoimmune encephalomyelitis in SJL/J mice through the inhibition of nuclear factor-kappa B signaling in B cells

Multiple sclerosis (MS) is a severe autoimmune disease leading to demyelination, followed by consequent axonal degeneration, causing sensory, motor, cognitive, and visual symptoms. Experimental autoimmune encephalomyelitis (EAE) is the most well-studied animal model of MS. Most current MS treatments are not completely effective, and severe side effects remain a great challenge. In this study, we report the therapeutic efficacy of PD98059, a potent mitogen-activated protein kinase inhibitor, on proteolipid protein (PLP)_139-151-induced EAE in SJL/J mice. Following the induction of EAE, mice were intraperitoneally treated with PD98059 (5 mg/kg for 14 days) daily from day 14 to day 28. This study investigated the effects of PD98059 on C-C motif chemokine receptor 6 (CCR6), CD14, NF-κB p65, IκBα, GM-CSF, iNOS, IL-6, TNF-α in CD45R⁺ B lymphocytes using flow cytometry. Furthermore, we analyzed the effect of PD98059 on CCR6, CD14, NF-κB p65, GM-CSF, iNOS, IL-6, and TNF-α mRNA and protein expression levels using qRT-PCR analysis in brain tissues. Mechanistic investigations revealed that PD98059-treated in mice with EAE had reduced CD45R⁺CCR6⁺, CD45R⁺CD14⁺, CD45R⁺NF-κB p65⁺, CD45R⁺GM-CSF⁺, CD45R⁺iNOS⁺, CD45R⁺IL-6⁺, and CD45R⁺TNF-α⁺ cells and increased CD45R⁺IκBα⁺ cells compared with vehicle-treated control mice in the spleen. Moreover, downregulation of CCR6, CD14, NF-κB p65, GM-CSF, iNOS, IL-6, and TNF-α mRNA expression level was observed in PD98059-treated mice with EAE compared with vehicle-treated control mice in the brain tissue. The results of this study demonstrate that PD98059 modulates inflammatory mediators through multiple cellular mechanisms. The results of this study suggest that PD98059 may be pursued as a therapeutic agent for the treatment of MS.

Understanding the development of Th2 cell-driven allergic airway disease in early life

Allergic diseases, including atopic dermatitis, allergic rhinitis, asthma, and food allergy, are caused by abnormal responses to relatively harmless foreign proteins called allergens found in pollen, fungal spores, house dust mites (HDM), animal dander, or certain foods. In particular, the activation of allergen-specific helper T cells towards a type 2 (Th2) phenotype during the first encounters with the allergen, also known as the sensitization phase, is the leading cause of the subsequent development of allergic disease. Infants and children are especially prone to developing Th2 cell responses after initial contact with allergens. But in addition, the rates of allergic sensitization and the development of allergic diseases among children are increasing in the industrialized world and have been associated with living in urban settings. Particularly for respiratory allergies, greater susceptibility to developing allergic Th2 cell responses has been shown in children living in urban environments containing low levels of microbial contaminants, principally bacterial endotoxins [lipopolysaccharide (LPS)], in the causative aeroallergens. This review highlights the current understanding of the factors that balance Th2 cell immunity to environmental allergens, with a particular focus on the determinants that program conventional dendritic cells (cDCs) toward or away from a Th2 stimulatory function. In this context, it discusses transcription factor-guided functional specialization of type-2 cDCs (cDC2s) and how the integration of signals derived from the environment drives this process. In addition, it analyzes observational and mechanistic studies supporting an essential role for innate sensing of microbial-derived products contained in aeroallergens in modulating allergic Th2 cell immune responses. Finally, this review examines whether hyporesponsiveness to microbial stimulation, particularly to LPS, is a risk factor for the induction of Th2 cell responses and allergic sensitization during infancy and early childhood and the potential factors that may affect early-age response to LPS and other environmental microbial components.

Amanita muscaria extract potentiates production of proinflammatory cytokines by dsRNA-activated human microglia

Recent interest in mushrooms and their components as potential therapies for mental health, along with recent government and health authority approvals, has necessitated a more comprehensive understanding of their effects on the cellular microenvironment of the brain. Amanita muscaria has been ingested as a treatment for a variety of ailments for centuries, most notably those affecting the central nervous system and conditions associated with neuroinflammation. However, the effects of these extracts on neuroinflammatory cells, such as microglia, are unknown. The effect of commercially-sourced A. muscaria extract (AME-1) on human microglial cell line (HMC3) expression of surface receptors such as CD86, CXCR4, CD45, CD125 and TLR4 was determined by flow cytometry. AME-1 upregulated expression of all of these receptors. The effect of AME-1 on HMC3 production of IL-8 and IL-6 was determined and compared to tumor necrosis factor (TNF), polyinosinic-polycytidylic acid [poly(I:C)], substance P and lipopolysaccharide (LPS), all known activators of HMC-3 and primary microglia. HMC3 produced both IL-8 and IL-6 when activated with LPS, TNF and poly(I:C) but not when they were activated with substance P. Although AME-1 at higher concentrations increased IL-8 production of HMC3 on its own, AME-1 notably potentiated HMC3 production of IL-8 in response to poly(I:C). AME-1 altered expression of toll-like receptor 3 (TLR3) mRNA but not surface protein by HMC3. AME-1 also did not significantly alter expression of retinoic acid-inducible gene I (RIG-I) or melanoma differentiation-associated protein 5 (MDA5), both cytosolic sensors of dsRNA. Metabolomics analysis showed that AME-1 contained several metabolites, including the autophagy inducer, trehalose. Like AME-1, trehalose also potentiated HMC3 poly(I:C) mediated production of IL-8. This study suggests that A. muscaria extracts can modify HMC3 inflammatory responses, possibly due to their trehalose content.

A novel Pseudorabies virus vaccine developed using HDR-CRISPR/Cas9 induces strong humoral and cellular immune response in mice

Outbreaks of Pseudorabies (PR) by numerous highly virulent and antigenic variant Pseudorabies virus (PRV) strains have been causing severe economic losses to the pig industry in China since 2011. However, current commercial vaccines are often unable to induce thorough protective immunity. In this study, a TK/gI/gE deleted recombinant PRV expressing GM-CSF was developed by using the HDR-CRISPR/Cas9 system. Here, a four-sgRNA along with the Cas9^D10A targeting system was utilized for TK/gI/gE gene deletion and GM-CSF insertion. Our study showed that the four-sgRNA targeting system appeared to have higher knock-in efficiency for PRVs editing. The replication of the recombinant PRVs were slightly lower than that of the parental strain, but they appeared to have similar properties in terms of growth curves and plaque morphology. The mice vaccinated with the recombinant PRV expressing GM-CSF via intramuscular injection showed no obvious clinical symptoms, milder pathological lesions, and were completely protected against wild-type PRV challenge. When compared to the triple gene-deleted PRV, the gB antibodies and neutralizing antibody titers were improved and the immunized mice appeared to have lower viral load and higher mRNA levels of IL-2, IL-4, IL-6, and IFN-γ in spleens. Our study offers a novel approach for recombinant PRV construction, and the triple gene-deleted PRV expressing GM-CSF could serve as a promising vaccine candidate for PR control.

New models of Parkinson's like neuroinflammation in human microglia clone 3: Activation profiles induced by INF-γ plus high glucose and mitochondrial inhibitors

Microglia activation and neuroinflammation have been extensively studied in murine models of neurodegenerative diseases; however, to overcome the genetic differences between species, a human cell model of microglia able to recapitulate the activation profiles described in patients is needed. Here we developed human models of Parkinson's like neuroinflammation by using the human microglia clone 3 (HMC3) cells, whose activation profile in response to classic inflammatory stimuli has been controversial and reported only at mRNA levels so far. In fact, we showed the increased expression of the pro-inflammatory markers iNOS, Caspase 1, IL-1β, in response to IFN-γ plus high glucose, a non-specific disease stimulus that emphasized the dynamic polarization and heterogenicity of the microglial population. More specifically, we demonstrated the polarization of HMC3 cells through the upregulation of iNOS expression and nitrite production in response to the Parkinson's like stimuli, 6-hydroxidopamine (6-OHDA) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), the latter depending on the NF-κB pathway. Furthermore, we identified inflammatory mediators that promote the pro-inflammatory activation of human microglia as function of different pathways that can simulate the phenotypic transition according to the stage of the pathology. In conclusion, we established and characterized different systems of HMC3 cells activation as in vitro models of Parkinson's like neuroinflammation.

Gut microbiota composition reflects disease progression, severity and outcome, and dysfunctional immune responses in patients with hypertensive intracerebral hemorrhage

OBJECTIVE

In this study, we aimed to explore the alterations in gut microbiota composition and cytokine responses related to disease progression, severity, and outcomes in patients with hypertensive intracerebral hemorrhage (ICH).

METHODS

Fecal microbiota communities of 64 patients with ICH, 46 coronary heart disease controls, and 23 healthy controls were measured by sequencing the V3-V4 region of the 16S ribosomal RNA (16S rRNA) gene. Serum concentrations of a broad spectrum of cytokines were examined by liquid chips and ELISA. Relationships between clinical phenotypes, microbiotas, and cytokine responses were analyzed in the group with ICH and stroke-associated pneumonia (SAP), the major complication of ICH.

RESULTS

In comparison with the control groups, the gut microbiota of the patients with ICH had increased microbial richness and diversity, an expanded spectrum of facultative anaerobes and opportunistic pathogens, and depletion of anaerobes. Enterococcus enrichment and Prevotella depletion were more significant in the ICH group and were associated with the severity and functional outcome of ICH. Furthermore, Enterococcus enrichment and Prevotella depletion were also noted in the SAP group in contrast to the non-SAP group. Enterococci were also promising factors in the prognosis of ICH. The onset of ICH induced massive, rapid activation of the peripheral immune system. There were 12 cytokines (Eotaxin, GM-CSF, IL-8, IL-9, IL-10, IL-12p70, IL-15, IL-23, IL-1RA, IP-10, RANTES, and TNF-α) changed significantly with prolongation of ICH, and the Th2 responses correlated with the 90-day outcomes. Cytokines TNF-α, IP-10, IL-1RA, IL-8, IL-18, and MIP-1β in SAP group significantly differed from non-SAP group. Among these cytokines, only IP-10 levels decreased in the SAP group. Enterococcus was positively associated with IL-1RA and negatively associated with IP-10, while Prevotella was inversely associated in both the ICH and SAP groups.

CONCLUSION

This study revealed that gut dysbiosis with enriched Enterococcus and depleted Prevotella increased the risk of ICH and subsequently SAP. The altered gut microbiota composition and serum cytokine profiles are potential biomarkers that reflect the inciting physiologic insult/stress involved with ICH.

Csf2ra deletion attenuates acute lung injuries induced by intratracheal inoculation of aerosolized ricin in mice

Specific therapeutics are not available for acute lung injury (ALI) induced by ricin toxin (RT). Inhibiting the host immune response in the course of pulmonary ricinosis is hypothesized to be of benefit and can be achieved by impairing granulocyte-macrophage colony-stimulating factor (GM-CSF) signaling, thereby reducing the pro-inflammatory response to exogenous foreign body invasion. However, it is unknown whether mice with impaired GM-CSF signaling can survive after RT inhalation. To test this, colony stimulating factor 2 receptor alpha (Csf2ra) knockout (KO) mice that lack GM-CSF signaling and wild-type (WT) mice models of intratracheal exposure to a lethal dose (2× LD₅₀) of RT were established. Survival was greater in Csf2ra KO mice 21 days after RT inhalation compared with WT mice. Highly co-expressed genes that probably attenuated the pro-inflammatory response in the lung of Csf2ra KO mice were identified. Bioinformatics analysis revealed that transcriptome changes involved mostly inflammation-related genes after RT exposure in both Csf2ra KO mice and WT mice. However, the activity levels of pro-inflammatory pathways, such as the TNF signaling pathway and NF-κB signaling pathway, in Csf2ra KO mice were significantly decreased and the degree of neutrophil chemotaxis and recruitment inhibited after RT-exposure relative to WT mice. RT-qPCR and flow cytometry validated results of RNA-Seq analysis. This work provides potential avenues for host-directed therapeutic applications that can mitigate the severity of ALI-induced by RT.

GM-CSF elicits antibodies to tumor-associated proteins when used as a prostate cancer vaccine adjuvant

Antibody responses to off-target cancer-associated proteins have been detected following immunotherapies for cancer, suggesting these may be the result of antigen spread. We have previously reported that serum antibodies to prostate cancer-associated proteins were detectable using a high-throughput peptide array. We hypothesized that the breadth of antibody responses elicited by a vaccine could serve as a measure of the magnitude of its induced antigen spread. Consequently, sera from patients with prostate cancer, treated prior to or after vaccination in one of four separate clinical trials, were evaluated for antibody responses to an array of 177,604 peptides derived from over 1600 prostate cancer-associated gene products. Antibody responses to the same group of 5680 peptides previously reported were identified following vaccinations in which patients were administered GM-CSF as an adjuvant, but not with vaccine in the absence of GM-CSF. Hence, antibody responses to off-target proteins following vaccination may not necessarily serve as evidence of antigen spread and must be interpreted with particular caution following vaccine strategies that use GM-CSF, as GM-CSF appears to have direct effects on the production of antibodies. The evaluation of T cell responses to non-target antigens is likely a preferred approach for detection of immune-mediated antigen spread.

Preventive effects of arctigenin from Arctium lappa L against LPS-induced neuroinflammation and cognitive impairments in mice

Arctigenin (Arc) is a phenylpropanoid dibenzylbutyrolactone lignan in Arctium lappa L, which has been widely applied as a traditional Chinese herbal medicine for treating inflammation. In the present study, we explored the neuroprotective effect and the potential mechanisms of arctigenin against LPS-evoked neuroinflammation, neurodegeneration, and memory impairments in the mice hippocampus. Daily administration of arctigenin (50 mg/kg per day, i.g.) for 28 days revealed noticeable improvements in spatial learning and memory deficits after exposure to LPS treatment. Arctigenin prevented LPS-induced neuronal/synaptic injury and inhibited the increases in Abeta (Aβ) generation and the levels of amyloid precursor protein (APP) and β-site amyloid precursor protein cleavage enzyme 1 (BACE1). Moreover, arctigenin treatment also suppressed glial activation and reduced the production of proinflammatory cytokines. In LPS-treated BV-2 microglial cells and mice, activation of the TLR4 mediated NF-κB signaling pathway was significantly suppressed by arctigenin administration. Mechanistically, arctigenin reduced the LPS-induced interaction of adiponectin receptor 1 (AdipoR1) with TLR4 and its coreceptor CD14 and inhibited the TLR4-mediated downstream inflammatory response. The outcomes of the current study indicate that arctigenin mitigates LPS-induced apoptotic neurodegeneration, amyloidogenesis and neuroinflammation as well as cognitive impairments, and suggest that arctigenin may be a potential therapeutic candidate for neuroinflammation/neurodegeneration-related diseases.

Microglial polarization in TBI: Signaling pathways and influencing pharmaceuticals

Traumatic brain injury (TBI) is a serious disease that threatens life and health of people. It poses a great economic burden on the healthcare system. Thus, seeking effective therapy to cure a patient with TBI is a matter of great urgency. Microglia are macrophages in the central nervous system (CNS) and play an important role in neuroinflammation. When TBI occurs, the human body environment changes dramatically and microglia polarize to one of two different phenotypes: M1 and M2. M1 microglia play a role in promoting the development of inflammation, while M2 microglia play a role in inhibiting inflammation. How to regulate the polarization direction of microglia is of great significance for the treatment of patients with TBI. The polarization of microglia involves many cellular signal transduction pathways, such as the TLR-4/NF-κB, JAK/STAT, HMGB1, MAPK, and PPAR-γ pathways. These provide a theoretical basis for us to seek therapeutic drugs for the patient with TBI. There are several drugs that target these pathways, including fingolimod, minocycline, Tak-242 and erythropoietin (EPO), and CSF-1. In this study, we will review signaling pathways involved in microglial polarization and medications that influence this process.

T cell transgressions: Tales of T cell form and function in diverse disease states

Insights into T cell form, function, and dysfunction are rapidly evolving. T cells have remarkably varied effector functions including protecting the host from infection, activating cells of the innate immune system, releasing cytokines and chemokines, and heavily contributing to immunological memory. Under healthy conditions, T cells orchestrate a finely tuned attack on invading pathogens while minimizing damage to the host. The dark side of T cells is that they also exhibit autoreactivity and inflict harm to host cells, creating autoimmunity. The mechanisms of T cell autoreactivity are complex and dynamic. Emerging research is elucidating the mechanisms leading T cells to become autoreactive and how such responses cause or contribute to diverse disease states, both peripherally and within the central nervous system. This review provides foundational information on T cell development, differentiation, and functions. Key T cell subtypes, cytokines that create their effector roles, and sex differences are highlighted. Pathological T cell contributions to diverse peripheral and central disease states, arising from errors in reactivity, are highlighted, with a focus on multiple sclerosis, rheumatoid arthritis, osteoarthritis, neuropathic pain, and type 1 diabetes.

Gas6/TAM Signalling Negatively Regulates Inflammatory Induction of GM-CSF in Mouse Brain Microglia

Microglia and astrocytes are the main CNS glial cells responsible for the neuroinflammatory response, where they release a plethora of cytokines into the CNS inflammatory milieu. The TAM (Tyro3, Axl, Mer) receptors and their main ligand Gas6 are regulators of this response, however, the underlying mechanisms remain to be determined. We investigated the ability of Gas6 to modulate the CNS glial inflammatory response to lipopolysaccharide (LPS), a strong pro-inflammatory agent, through a qPCR array that explored Toll-like receptor signalling pathway-associated genes in primary cultured mouse microglia. We identified the Csf2 gene, encoding granulocyte-macrophage colony-stimulating factor (GM-CSF), as a major Gas6 target gene whose induction by LPS was markedly blunted by Gas6. Both the Csf2 gene induction and the suppressive effect of Gas6 on this were emulated through measurement of GM-CSF protein release by cells. We found distinct profiles of GM-CSF induction in different glial cell types, with microglia being most responsive during inflammation. Also, Gas6 markedly inhibited the LPS-stimulated nuclear translocation of NF-κB p65 protein in microglia. These results illustrate microglia as a major resident CNS cellular source of GM-CSF as part of the neuroinflammatory response, and that Gas6/TAM signalling inhibits this response through suppression of NF-κB signalling.

Association of CD14 genetic variants and circulating level with systemic lupus erythematosus risk in Egyptian children and adolescents

Aim: To demonstrate whether sCD14 and CD14 (rs2569190 A/G and rs2569191 C/T) genetic variants are associated with systemic lupus erythematosus (SLE) risk, for the first time, in Egyptian pediatrics and adolescents. Materials & methods: sCD14 concentrations were determined in plasma of 95 SLE cases and 98 healthy controls using ELISA assay. Genotyping was performed using TaqMan technology. Results: sCD14 levels were elevated in SLE. Individuals with T, CT and TT genotypes in rs2569191 were of significant risk (odds ratio = 1.471-2.035, 95% CI = 1.138-3.471) and those with combined CT+TT and haplotype GT were of higher risk of SLE (odds ratio = 1.660-1.758, 95% CI = 1.003-3.106, p < 0.05). sCD14 levels and CD14 polymorphism were not correlated with SLE clinical and laboratory features. Conclusion: In SLE, sCD14 levels are associated with rs2569190 A/G. Genotype CT+TT in rs2569191 C/T and haplotype GT are associated with SLE risk in Egyptian pediatric and adolescents.

Colony stimulating factors in the nervous system

Although traditionally seen as regulators of hematopoiesis, colony-stimulating factors (CSFs) have emerged as important players in the nervous system, both in health and disease. This review summarizes the cellular sources, patterns of expression and physiological roles of the macrophage (CSF-1, IL-34), granulocyte-macrophage (GM-CSF) and granulocyte (G-CSF) colony stimulating factors within the nervous system, with a particular focus on their actions on microglia. CSF-1 and IL-34, via the CSF-1R, are required for the development, proliferation and maintenance of essentially all CNS microglia in a temporal and regional specific manner. In contrast, in steady state, GM-CSF and G-CSF are mainly involved in regulation of microglial function. The alterations in expression of these growth factors and their receptors, that have been reported in several neurological diseases, are described and the outcomes of their therapeutic targeting in mouse models and humans are discussed.

Microglia and BDNF at the crossroads of stressor related disorders: Towards a unique trophic phenotype

Stressors ranging from psychogenic/social to neurogenic/injury to systemic/microbial can impact microglial inflammatory processes, but less is known regarding their effects on trophic properties of microglia. Recent studies do suggest that microglia can modulate neuronal plasticity, possibly through brain derived neurotrophic factor (BDNF). This is particularly important given the link between BDNF and neuropsychiatric and neurodegenerative pathology. We posit that certain activated states of microglia play a role in maintaining the delicate balance of BDNF release onto neuronal synapses. This focused review will address how different "activators" influence the expression and release of microglial BDNF and address the question of tropomyosin receptor kinase B (TrkB) expression on microglia. We will then assess sex-based differences in microglial function and BDNF expression, and how microglia are involved in the stress response and related disorders such as depression. Drawing on research from a variety of other disorders, we will highlight challenges and opportunities for modulators that can shift microglia to a "trophic" phenotype with a view to potential therapeutics relevant for stressor-related disorders.

FGF21 alleviates chronic inflammatory injury in the aging process through modulating polarization of macrophages

Previous studies reported that FGF21 prolongs life span and delays the body senescence, but the mechanism is not clear. The present study was designed to investigate the effects of FGF21 on hepatic senescence in aging mice and further research the mechanism. The 14-month-old male mice were administered with PBS, FGF21 or metformin once daily for 6 months. Results showed that FGF21 alleviated liver injury and inhibited accumulation of senescence markers SASP, P53 and P16 in the livers of aging mice. Subsequently we found that the aging mice treated by FGF21 showed transition of type 1 macrophages (M1) to type 2 macrophages (M2) in the livers. Next, we used THP-1 macrophages triggered by LPS to study effects of FGF21 on macrophages. Macrophages triggered by LPS exhibited features of M1, but the addition of FGF21 decreased the expression of M1 markers, and promoted the macrophages to exhibit features of M2. Results showed that the effects of FGF21 on macrophages were associated with the AMPK pathway. After adding AMPK inhibitor, the effects of FGF21 were inhibited, which was associated with the NF-κB signaling pathway. Finally, co-culturing differentiated macrophages and hepatocytes, we found that the large amount of pro-inflammatory factors such as IL-6 promoted hepatocyte senescence, which exhibited enhanced P53, P16 and β-galactosidase. This was contrary to hepatocytes co-cultured with macrophages treated by FGF21. These results indicate that FGF21 alleviates hepatic senescence injury by modulating the polarization of macrophages through the AMPK /NF-κB signaling pathway.

Inhibition of TLR4 Signaling Impedes Tumor Growth in Colitis-Associated Colon Cancer

Patients suffering from ulcerative colitis are at increased risk of developing colorectal cancer. Although the exact underlying mechanisms of inflammation-associated carcinogenesis remain unknown, the intestinal microbiota as well as pathogenic bacteria are discussed as contributors to inflammation and colitis-associated colon cancer (CAC). In the present study, we analyzed the impact of TLR4, the receptor for Gram-negative bacteria derived lipopolysaccharides, on intestinal inflammation and tumorigenesis in a murine model of CAC. During the inflammatory phases of CAC development, we observed a strong upregulation of Tlr4 expression in colonic tissues. Blocking of TLR4 signaling by a small-molecule-specific inhibitor during the inflammatory phases of CAC strongly diminished the development and progression of colonic tumors, which was accompanied by decreased numbers of infiltrating macrophages and reduced colonic pro-inflammatory cytokine levels compared to CAC control mice. Interestingly, inhibiting bacterial signaling by antibiotic treatment during the inflammatory phases of CAC also protected mice from severe intestinal inflammation and almost completely prevented tumor growth. Nevertheless, application of antibiotics involved rapid and severe body weight loss and might have unwanted side effects. Our results indicate that bacterial activation of TLR4 on innate immune cells in the colon triggers inflammation and promotes tumor growth. Thus, the inhibition of the TLR4 signaling during intestinal inflammation might be a novel approach to impede CAC development.

Immune and vascular contributions to organogenesis of the testis and ovary

Gonad development is a highly regulated process that coordinates cell specification and morphogenesis to produce sex-specific organ structures that are required for fertility, such as testicular seminiferous tubules and ovarian follicles. While sex determination occurs within specialized gonadal supporting cells, sexual differentiation is evident throughout the entire organ, including within the interstitial compartment, which contains immune cells and vasculature. While immune and vascular cells have been traditionally appreciated for their supporting roles during tissue growth and homeostasis, an increasing body of evidence supports the idea that these cell types are critical drivers of sexually dimorphic morphogenesis of the gonad. Myeloid immune cells, such as macrophages, are essential for multiple aspects of gonadogenesis and fertility, including for forming and maintaining gonadal vasculature in both sexes at varying stages of life. While vasculature is long known for supporting organ growth and serving as an export mechanism for gonadal sex steroids in utero, it is also an important component of fetal testicular morphogenesis and differentiation; additionally, it is vital for ovarian corpus luteal function and maintenance of pregnancy. These findings point toward a new paradigm in which immune cells and blood vessels are integral components of sexual differentiation and organogenesis. In this review, we discuss the state of the field regarding the diverse roles of immune and vascular cells during organogenesis of the testis and ovary and highlight outstanding questions in the field that could stimulate new research into these previously underappreciated constituents of the gonad.

Preventive electroacupuncture ameliorates D-galactose-induced Alzheimer's disease-like inflammation and memory deficits, probably via modulating the microbiota-gut-brain axis

OBJECTIVES

We aimed to observe the effects of preventive electroacupuncture (EA) on the microbiota-gut-brain axis and spatial learning and memory deficits and to investigate the possible mechanism using D-galactose (D-gal)-induced aging rats.

MATERIALS AND METHODS

D-gal was intraperitoneally injected to establish the aging model. We used Morris water maze to detect spatial learning and memory function of rats. RT-PCR was applied to test targeted gut microbes. The expression of zonula occludens-1 (ZO-1) and Toll-like receptor 4 (TLR4)/nuclear factor (NF)-κB pathway proteins were detected by Western blotting. ELISA was employed to evaluate the level of lipopolysaccharides (LPS), diamine oxidase (DAO) and S-100β. Additionally, we observed ionized calcium-binding adapter molecule-1 (Iba-1) expression in the hippocampal CA1 area by immunofluorescence.

RESULTS

Morris water maze test showed decreased mean escape latency and increased target quadrant time after EA treatment. The gut microbiota composition has been modified in EA treated rats. Molecular examination indicated that expression of ZO-1 was improved and the the concentration of LPS in blood and hippocampus were reduced in EA treated rats. Further, we observed an inhibition of activated microglia and TLR4/NF-κB pathway in EA groups.

CONCLUSION

Preventive EA may alleviate the impairments of the microbiota-gut-brain axis and spatial learning and memory in aging, and the mechanism may be related to the inhibition of TLR4/NF-kB signaling pathway. The combination of acupoints GV20 and ST36 can enhance the therapeutic effect in aging rats.

Granulocyte macrophage colony-stimulating factor has come of age: From a vaccine adjuvant to antiviral immunotherapy

GM-CSF acts as a pro-inflammatory cytokine and a key growth factor produced by several immune cells such as macrophages and activated T cells. In this review, we discuss recent studies that point to the crucial role of GM-CSF in the immune response against infections. Upon induction, GM-CSF activates four main signalling networks including the JAK/STAT, PI3K, MAPK, and NFκB pathways. Many of these transduction pathways such as JAK/STAT signal via proteins commonly activated with other antiviral signalling cascades, such as those induced by IFNs. GM-CSF also helps defend against respiratory infections by regulating alveolar macrophage differentiation and enhancing innate immunity in the lungs. Here, we also summarize the numerous clinical trials that have taken advantage of GM-CSF's mechanistic attributes in immunotherapy. Moreover, we discuss how GM-CSF is used as an adjuvant in vaccines and how its activity is interfered with to reduce inflammation such as in the case of COVID-19. This review brings forth the current knowledge on the antiviral actions of GM-CSF, the associated signalling cascades, and its application in immunotherapy.

Organotypic Brain Slice Culture Microglia Exhibit Molecular Similarity to Acutely-Isolated Adult Microglia and Provide a Platform to Study Neuroinflammation

Microglia are central nervous system (CNS) resident immune cells that have been implicated in neuroinflammatory pathogenesis of a variety of neurological conditions. Their manifold context-dependent contributions to neuroinflammation are only beginning to be elucidated, which can be attributed in part to the challenges of studying microglia in vivo and the lack of tractable in vitro systems to study microglia function. Organotypic brain slice cultures offer a tissue-relevant context that enables the study of CNS resident cells and the analysis of brain slice microglial phenotypes has provided important insights, in particular into neuroprotective functions. Here we use RNA sequencing, direct digital quantification of gene expression with nCounter® technology and targeted analysis of individual microglial signature genes, to characterize brain slice microglia relative to acutely-isolated counterparts and 2-dimensional (2D) primary microglia cultures, a widely used in vitro surrogate. Analysis using single cell and population-based methods found brain slice microglia exhibited better preservation of canonical microglia markers and overall gene expression with stronger fidelity to acutely-isolated adult microglia, relative to in vitro cells. We characterized the dynamic phenotypic changes of brain slice microglia over time, after plating in culture. Mechanical damage associated with slice preparation prompted an initial period of inflammation, which resolved over time. Based on flow cytometry and gene expression profiling we identified the 2-week timepoint as optimal for investigation of microglia responses to exogenously-applied stimuli as exemplified by treatment-induced neuroinflammatory changes observed in microglia following LPS, TNF and GM-CSF addition to the culture medium. Altogether these findings indicate that brain slice cultures provide an experimental system superior to in vitro culture of microglia as a surrogate to investigate microglia functions, and the impact of soluble factors and cellular context on their physiology.

CD8+ T Cell-Mediated Mechanisms Contribute to the Progression of Neurocognitive Impairment in Both Multiple Sclerosis and Alzheimer's Disease?

Neurocognitive impairment (NCI) is one of the most relevant clinical manifestations of multiple sclerosis (MS). The profile of NCI and the structural and functional changes in the brain structures relevant for cognition in MS share some similarities to those in Alzheimer's disease (AD), the most common cause of neurocognitive disorders. Additionally, despite clear etiopathological differences between MS and AD, an accumulation of effector/memory CD8+ T cells and CD8+ tissue-resident memory T (Trm) cells in cognitively relevant brain structures of MS/AD patients, and higher frequency of effector/memory CD8+ T cells re-expressing CD45RA (TEMRA) with high capacity to secrete cytotoxic molecules and proinflammatory cytokines in their blood, were found. Thus, an active pathogenetic role of CD8+ T cells in the progression of MS and AD may be assumed. In this mini-review, findings supporting the putative role of CD8+ T cells in the pathogenesis of MS and AD are displayed, and putative mechanisms underlying their pathogenetic action are discussed. A special effort was made to identify the gaps in the current knowledge about the role of CD8+ T cells in the development of NCI to "catalyze" translational research leading to new feasible therapeutic interventions.

GM-CSF: A Promising Target in Inflammation and Autoimmunity

The cytokine, granulocyte macrophage-colony stimulating factor (GM-CSF), was firstly identified as being able to induce in vitro the proliferation and differentiation of bone marrow progenitors into granulocytes and macrophages. Much preclinical data have indicated that GM-CSF has a wide range of functions across different tissues in its action on myeloid cells, and GM-CSF deletion/depletion approaches indicate its potential as an important therapeutic target in several inflammatory and autoimmune disorders, for example, rheumatoid arthritis. In this review, we discuss briefly the biology of GM-CSF, raise some current issues and questions pertaining to this biology, summarize the results from preclinical models of a range of inflammatory and autoimmune disorders and list the latest clinical trials evaluating GM-CSF blockade in such disorders.

Site-specific metastasis: A cooperation between cancer cells and the metastatic microenvironment

The conclusion derived from the information provided in this review is that disseminating tumor cells (DTC) collaborate with the microenvironment of a future metastatic organ site in the establishment of organ‐specific metastasis. We review the basic principles of site‐specific metastasis and the contribution of the cross talk between DTC and the microenvironment of metastatic sites (metastatic microenvironment [MME]) to the establishment of the organ‐specific premetastatic niche; the targeted migration of DTC to the endothelium of the future organ‐specific metastasis; the transmigration of DTC to this site and the seeding and colonization of DTC in their future MME. We also discuss the role played by DTC‐MME interactions on tumor dormancy and on the differential response of tumor cells residing in different MMEs to antitumor therapy. Finally, we summarize some studies dealing with the effects of the MME on a unique site‐specific metastasis—brain metastasis.

Ipriflavone and Ipriflavone loaded albumin nanoparticles reverse lipopolysaccharide induced neuroinflammation in rats

BACKGROUND

Neuroinflammation causes neurodegenerative conditions like Alzheimer's disease (AD). Ipriflavone (IP), therapeutic compound to postmenopausal osteoporosis, has limited estrogenic activity and is accounted as AChE inhibitor. The developing of drug delivery systems to enable drug targeting to specific sites increases the drug therapeutic effect.

OBJECTIVE

The aim of the present study was to formulate and evaluate ipriflavone loaded albumin nanoparticles (IP-Np) along with free ipriflavone against lipopolysaccharide (LPS) induced neuroinflammation in rats.

METHODS

Neuroinflammation was induced by intra-peritoneal (i.p) injection of LPS (250 μg/kg rat body weight) then treatments were conducted with (1) ipriflavone at two doses 50 mg/kg and 5 mg/kg, (2) IP-Np (5 mg ipriflavone/kg) or (3) IP-Np coated with polysorbate 80 (IP-Np-T80) (5 mg ipriflavone/kg). The alteration of the inflammatory response in male adult Wistar rats' brain hippocampus was investigated by examining associated indices using biochemical and molecular analyses.

RESULTS

A significant upsurge in inflammatory mediators and decline in antioxidant status were observed in LPS-induced rats. In one hand, ipriflavone (50 mg/kg), IP-Np and IP-Np-T80 ameliorated LPS induced brain hippocampal inflammation where they depreciated the level of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) and enhanced antioxidant status. In another hand, ipriflavone at dose (5 mg/kg) didn't show the same therapeutic effect.

CONCLUSION

The current study provides evidence for the potential neuroprotective effect of ipriflavone (50 mg/kg) against LPS-induced neuroinflammation in rats through its anti-inflammatory and antioxidant activities. Moreover, nanoparticles significantly attenuated neuroinflammation in concentration lower than the effective therapeutic dose of free drug ten times.

Rhein Suppresses Neuroinflammation via Multiple Signaling Pathways in LPS-Stimulated BV2 Microglia Cells

As a bioactive absorbed compound of rhubarb, Rhein is applied for the treatment of brain injury. However, the underlying pharmacological mechanisms remain unclear. In this study, we aimed to explore antineuroinflammatory functions and underlying mechanisms of Rhein in vitro. BV2 microglia cells were chosen and irritated by LPS. The influence of Rhein on cell viability was determined using MTT assay. We finely gauged the proinflammatory cytokines of TNF-α and IL-1β through tests of immunofluorescence staining, ELISA, RT-qPCR, and western blot. Additionally, mediators including IL-6, IL-12, iNOS, and IL-10 were surveyed by ELISA. Furthermore, protein levels of the underlying signaling pathways (PI3K/Akt, p38, ERK1/2, and TLR4/NF-κB) were tested adopting western blot. We found that Rhein reduced the secretion of pivotal indicators including TNF-α and IL-1β, effectively restraining their mRNA and protein expression in LPS-activated BV2 microglial cells. Besides, Rhein treatment demoted the production of IL-6, IL-12, and iNOS and promoted the excretion of IL-10. Subsequent mechanistic experiments revealed that Rhein obviously downregulated the phosphorylation levels of PI3K, Akt, p38, and ERK1/2 and simultaneously upregulated the PTEN expression. In addition, Rhein antagonized the increase of TLR4, p-IκBα, and NF-κB. In summary, Rhein suppresses neuroinflammation via multiple signaling pathways (PI3K/Akt, p38, ERK1/2, and TLR4/NF-κB) in LPS-stimulated BV2 microglia cells. This study highlights a natural agent for prevention and treatment of neuroinflammation.

Targeting Granulocyte-Monocyte Colony-Stimulating Factor Signaling in Rheumatoid Arthritis: Future Prospects

Rheumatoid arthritis (RA) is a systemic, autoimmune disease that affects joints and extra-articular structures. In the last decade, the management of this chronic disease has dramatically changed with the introduction of several targeted mechanisms of action, such as tumor necrosis factor-α inhibition, T-cell costimulation inhibition, B-cell depletion, interleukin-6 blockade, and Janus kinase inhibition. Beyond its well-known hematopoietic role on the proliferation and differentiation of myeloid cells, granulocyte-monocyte colony-stimulating factor (GM-CSF) is a proinflammatory mediator acting as a cytokine, with a proven pathogenetic role in autoimmune disorders such as RA. In vitro studies clearly demonstrated the effect of GM-CSF in the communication between resident tissue cells and activated macrophages at chronic inflammation sites, and confirmed the elevation of GM-CSF levels in inflamed synovial tissue of RA subjects compared with healthy controls. Moreover, a pivotal role of GM-CSF in the perception of pain has been clearly confirmed. Therefore, blockade of the GM-CSF pathway by monoclonal antibodies directed against the cytokine itself or its receptor has been investigated in refractory RA patients. Overall, the safety profile of GM-CSF inhibitors seems to be very favorable, with a particularly low incidence of infectious complications. The efficacy of this new mechanism of action is comparable with main competitors, even though the response rates reported in phase II randomized controlled trials (RCTs) appear to be numerically lower than the response rates observed with other biological disease-modifying antirheumatic drugs already licensed for RA. Mainly because of this reason, nowadays the development program of most GM-CSF blockers for RA has been discontinued, with the exception of otilimab, which is under evaluation in two phase III RCTs with a head-to head non-inferiority design against tofacitinib. These studies will likely be useful for better defining the potential role of GM-CSF inhibition in the therapeutic algorithm of RA. On the other hand, the potential role of GM-CSF blockade in the treatment of other rheumatic diseases is now under investigation. Phase II trials are ongoing with the aim of evaluating mavrilimumab for the treatment of giant cell arteritis, and namilumab for the treatment of spondyloarthritis. Moreover, GM-CSF inhibitors have been tested in osteoarthritis and diffuse subtype of systemic sclerosis. This review aims to describe in detail the available evidence on the GM-CSF blocking pathway in RA management, paving the way to a possible alternative treatment for RA patients. Novel insights regarding the potential use of GM-CSF blockers for alternative indications will be also addressed.

SOCS3 Attenuates GM-CSF/IFN-γ-Mediated Inflammation During Spontaneous Spinal Cord Regeneration

SOCS3, a feedback inhibitor of the JAK/STAT signal pathway, negatively regulates axonal regrowth and inflammation in the central nervous system (CNS). Here, we demonstrated a distinct role of SOCS3 in the injured spinal cord of the gecko following tail amputation. Severing the gecko spinal cord did not evoke an inflammatory cascade except for an injury-stimulated elevation of the granulocyte/macrophage colony-stimulating factor (GM-CSF) and interferon gamma (IFN-γ) cytokines. Simultaneously, the expression of SOCS3 was upregulated in microglia, and unexpectedly not in neurons. Enforced expression of SOCS3 was sufficient to suppress the GM-CSF/IFN-γ-driven inflammatory responses through its KIR domain by attenuating the activities of JAK1 and JAK2. SOCS3 was also linked to GM-CSF/IFN-γ-induced cross-tolerance. Transfection of adenovirus overexpressing SOCS3 in the injured cord resulted in a significant decrease of inflammatory cytokines. These results reveal a distinct role of SOCS3 in the regenerating spinal cord, and provide new hints for CNS repair in mammals.

Implication of HMGB1 signaling pathways in Amyotrophic lateral sclerosis (ALS): From molecular mechanisms to pre-clinical results

Amyotrophic lateral sclerosis (ALS) is a devastating and rapidly progressing neurodegenerative disorder with no effective disease-modifying treatment up to date. The underlying molecular mechanisms of ALS are not yet completely understood. However, the critical role of the innate immune system and neuroinflammation in ALS pathogenesis has gained increased attention. High mobility group box 1 (HMGB1) is a typical damage-associated molecular pattern (DAMP) molecule, acting as a pro-inflammatory cytokine mainly through activation of its principal receptors, the receptor for advanced glycation end products (RAGE) and toll-like receptor 4 (TLR4) which are crucial components of the innate immune system. HMGB1 is an endogenous ligand for both RAGE and TLR4 that mediate its biological effects. Herein, on the ground of pre-clinical findings we unravel the underlying mechanisms behind the plausible contribution of HMGB1 and its receptors (RAGE and TLR4) in the ALS pathogenesis. Furthermore, we provide an account of the therapeutic outcomes associated with inhibition/blocking of HMGB1 receptor signalling in preventing motor neuron's death and delaying disease progression in ALS experimental models. There is strong evidence that HMGB1, RAGE and TLR4 signaling axes might present potential targets against ALS, opening a novel headway in ALS research that could plausibly bridge the current treatment gap.

The CD14 gene -159C/T polymorphism and the risk of ischemic stroke: a meta-analysis

BACKGROUND

To investigate the association between the CD14 -159C/T polymorphism and ischemic stroke (IS).

METHODS

Relevant literature was searched by retrieving EMBASE, Web of Science, Chinese National Knowledge Infrastructure, and PubMed databases. R version 3.33 software was applied to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Seven qualified studies with a total of 2058 IS patients and 2123 controls were included. There was no significant association between the CD14 -159C/T polymorphism and IS risk in the total population (TT vs CC: OR = 0.84, 95% CI = 0.58-1.20; CT vs CC: OR = 0.96, 95% CI = 0.82-1.12; dominant model: OR = 1.02, 95% CI = 0.80-1.30; recessive model: OR = 0.82, 95% CI = 0.57-1.19). Similarly, subgroup analysis according to ethnicity and Hardy-Weinberg equilibrium also found no significant interrelation.

CONCLUSION

Our findings suggest that the CD14 -159C/T polymorphism does not contribute to the risk of IS. Well-designed studies with more subjects are required to further validate these results.

The roles played by TLR4 in the pathogenesis of multiple sclerosis; A systematic review article

Multiple sclerosis (MS) is a world-wide pro-inflammatory based disease, which is prevalent among young individuals. The etiology of the disease and its related complications are yet to be clarified. It has been hypothesized that environmental factors, including pathogen-associated molecular patterns (PAMPs) and the internal factors such as damage-associated molecular patterns (DAMPs), may be the most important inducers/stimulators of the disorder and its related complications. Previous investigations proved that pathogen recognition receptors (PRRs) are the main sensors for the PAMPs and DAMPs. Therefore, it seems that the PRRs have been considered to be the plausible molecules participating in the etiology of MS. Toll-like receptors (TLRs) have been the widely studied PRRs and their roles have been documented in human-related diseases. TLR4 is the main PRR expressed on the cell surface of several immune cells including macrophages and dendritic cells. Several investigations reported that TLR4 to be the main molecule involved in the pathogenesis of pro-inflammatory based diseases. Thus, it has been hypothesized that TLR4 may be a part of the MS puzzle. This review article discusses the role of TLR4 in the MS pathogenesis using recent in vitro and in vivo investigations.

Granulocyte-Macrophage Colony Stimulating Factor As an Indirect Mediator of Nociceptor Activation and Pain

The interaction between the immune system and the nervous system has been at the center of multiple research studies in recent years. Whereas the role played by cytokines as neuronal mediators is no longer contested, the mechanisms by which cytokines modulate pain processing remain to be elucidated. In this study, we have analyzed the involvement of granulocyte-macrophage colony stimulating factor (GM-CSF) in nociceptor activation in male and female mice. Previous studies have suggested GM-CSF might directly activate neurons. However, here we established the absence of a functional GM-CSF receptor in murine nociceptors, and suggest an indirect mechanism of action, via immune cells. We report that GM-CSF applied directly to magnetically purified nociceptors does not induce any transcriptional changes in nociceptive genes. In contrast, conditioned medium from GM-CSF-treated murine macrophages was able to drive nociceptor transcription. We also found that conditioned medium from nociceptors treated with the well established pain mediator, nerve growth factor, could also modify macrophage gene transcription, providing further evidence for a bidirectional crosstalk.SIGNIFICANCE STATEMENT The interaction of the immune system and the nervous system is known to play an important role in the development and maintenance of chronic pain disorders. Elucidating the mechanisms of these interactions is an important step toward understanding, and therefore treating, chronic pain disorders. This study provides evidence for a two-way crosstalk between macrophages and nociceptors in the peripheral nervous system, which may contribute to the sensitization of nociceptors by cytokines in pain development.

Microglial activation and responses to vasculature that result from an acute LPS exposure

Bacterial cell wall endotoxins, i.e. lipopolysaccharides (LPS), are some of the original compounds shown to evoke the classic signs of systemic inflammation/innate immune response and neuroinflammation. The term neuroinflammation often is used to infer the elaboration of proinflammatory mediators by microglia elicited by neuronal targeted activity. However, it also is possible that the microglia are responding to vasculature through several signaling mechanisms. Microglial activation relative to the vasculature in the hippocampus and parietal cortex was determined after an acute exposure of a single subcutaneous injection of 2 mg/kg LPS. Antibodies to allograft inflammatory factor (Aif1, a.k.a. Iba1) were used to track and quantify morphological changes in microglia. Immunostaining of platelet/endothelial cell adhesion molecule 1 (Pecam1, a.k.a. Cd31) was used to visualize vasculature in the forebrain and glial acidic fibrillary protein (GFAP) to visualize astrocytes. Neuroinflammation and other aspects of neurotoxicity were evaluated histologically at 3 h, 6 h, 12 h, 24 h, 3 d and 14 d following LPS exposure. LPS did not cause neurodegeneration as determined by Fluoro Jade C labeling. Also, there were no signs of mouse IgG leakage from brain vasculature due to LPS. Some changes in microglia size occurred at 6 h, but by 12 h microglial activation had begun with the combined soma and proximal processes size increasing significantly (1.5-fold). At 24 h, almost all the microglia soma and proximal processes in the hippocampus, parietal cortex, and thalamus were closely associated with the vasculature and had increased almost 2.0-fold in size. In many areas where microglia were juxtaposed to vasculature, astrocytic endfeet appeared to be displaced. The microglial activation had subsided slightly by 3 d with microglial size 1.6-fold that of control. We hypothesize that acute LPS activation can result in vascular mediated microglial responses through several mechanisms: 1) binding to Cd14 and Tlr4 receptors on microglia processes residing on vasculature; 2) damaging vasculature and causing the release of cytokines; and 3) possibly astrocytic endfeet damage resulting in cytokine release. These acute responses may serve as an adaptive mechanism to exposure to circulating LPS where the microglia surround the vasculature. This could further prevent the pathogen(s) circulating in blood from entering the brain. However, diverting microglial interactions away from synaptic remodeling and other types of microglial interactions with neurons may have adverse effects on neuronal function.

Association of CD14 gene -260C>T and -561C>T polymorphisms with cancer susceptibility: A meta-analysis

BACKGROUND

Two polymorphisms, -260C>T (rs2569190) and -561C>T (rs5744455), in the CD14 gene have been implicated in susceptibility to cancer. However, the results remain inconclusive. The current meta-analysis was carried out aiming to confirm the function of these two polymorphisms on the susceptibility of cancer.

METHODS

We collected eligible studies from databases, including PubMed, EMBASE, CNKI, Wanfang, and VIP (Weipu). We used logistic regression calculation to compute odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

After strict selection, 24 studies with 5854 cases and 10339 controls for -260C>T and seven studies with 1809 cases and 7289 controls for -561C>T were finally enlisted into our analysis reference material. Pool results revealed that neither -260C>T, nor -561C>T was found to have any association with overall cancer susceptibility. Nevertheless, when stratified by cancer type, we detected a decreased risk associated with other cancers in a heterozygous model (OR = 0.69, 95% CI = 0.51-0.93, p = 0.014) and a dominant model (OR = 0.70, 95% CI = 0.53-0.93, p = 0.012) for -561C>T. An increased risk was found in other cancers under an allele model (OR = 1.29, 95% CI = 1.03-1.62, p = 0.026), in laryngeal cancer under a dominant model (OR = 1.38, 95% CI = 1.11-1.71, p = 0.003) and for a score ≤ 9 under a recessive model (OR = 1.45, 95% CI = 1.09-1.91, p = 0.009) for -561C>T.

CONCLUSIONS

In the present study, we conclude that the CD14 -260C>T and -561C>T polymorphisms might not be associated with overall cancer risk. Further studies are encouraged to confirm this conclusion.

Current Perspectives in Immunotherapy for Liver Cancer

Liver cancer is a particularly aggressive group of malignancies with historically low survival rates. Despite advancements in cancer treatments in general in the last few decades, incidence and mortality have not changed. Even though some phase 1 and 2 studies have shown promising results, many medication have failed to reach a sustainable level of efficacy to move into the clinical setting. Immunotherapy drugs have shown impressive results in the treatment of specific immunogenic cancers, prompting the possibility of their use in liver cancers. Immunotherapy medications approved for other cancers have received FDA accelerated approval for treatment of hepatocellular carcinoma. But, these approvals are contingent upon verification and description of clinical benefit in confirmatory trials. With more treatments in development involving cancer vaccines and natural killer cell-mediated therapy, liver cancer treatment is being reinvigorated with a broad array of new treatment angles. In this review article, we discuss these treatments, focusing on mechanism of action and clinical trials. Much needed advancements in treating late- and early-stage liver cancers will require new and innovative immunotherapeutic treatments.

Meisoindigo Protects Against Focal Cerebral Ischemia-Reperfusion Injury by Inhibiting NLRP3 Inflammasome Activation and Regulating Microglia/Macrophage Polarization via TLR4/NF-κB Signaling Pathway

Ischemic stroke is a devastating disease with long-term disability. However, the pathogenesis is unclear and treatments are limited. Meisoindigo, a second-generation derivative of indirubin, has general water solubility and is well-tolerated. Previous studies have shown that meisoindigo reduces inflammation by inhibiting leukocyte chemotaxis and migration. In the present study, we investigated the hypothesis that meisoindigo was also protective against ischemic stroke, then evaluated its underlying mechanisms. In vivo, adult male C57BL/6J wild-type mice were used to produce a middle cerebral artery occlusion (MCAO) stroke model. On day three after reperfusion, obvious improvement in neurological scores, infarct volume reduction and cerebral edema amelioration were observed in meisoindigo treatment. Moreover, immunofluorescence staining and western-blot showed that the expression of NLRP3 inflammasome and its associated proteins in neurons and microglia was inhibited by meisoindigo. The effects of Meisoindigo on NLRP3 inflammasome inactivation and increased the M2 phenotype of microglia/macrophage through shifting from a M1 phenotype, which was possibly mediated by inhibition of TLR4/NF-κB. Furthermore, we verified the inhibitory effect of meisoindigo on TLR4/NF-κB signaling pathway, and found that meisoindigo treatment could significantly suppressed the expression of TLR4/NF-κB pathway-associated proteins in a dose-dependent manner, meanwhile, which resulted in downregulation of HMGB1 and IL-1β. Next, we established an in vitro oxygen glucose deprivation/Reperfusion (OGD/R) model in HT-22 and BV2 cells to simulate ischemic conditions. Cytotoxicity assay showed that meisoindigo substantially improved relative cell vitality and in HT-22 and BV2 cells following OGD/R in vitro. After suffering OGD/R, the TLR4/NF-κB pathway was activated, the expression of NLRP3 inflammasome-associated proteins and M1 microglia/macrophage were increased, but meisoindigo could inhibit above changes in both HT-22 and BV2 cells. Additionally, though lipopolysaccharide stimulated the activation of TLR4 signaling in OGD/R models, meisoindigo co-treatment markedly reversed the upregulation of TLR4 and following activation of NLRP3 inflammasome and polarization of M1 microglia/macrophages mediated by TLR4. Overall, we demonstrate for the first time that meisoindigo post-treatment alleviates brain damage induced by ischemic stroke in vivo and in vitro experiments through blocking activation of the NLRP3 inflammasome and regulating the polarization of microglia/macrophages via inhibition of the TLR4/NF-κB signaling pathway.

Long-Term Microgliosis Driven by Acute Systemic Inflammation

Severe sepsis, a systemic inflammatory response to infection, is an increasing cause of morbidity in intensive care units. During sepsis, the vasculature is profoundly altered, leading to release of microbial virulence factors and proinflammatory mediators to surrounding tissue, causing severe systemic inflammatory responses and hypoxic injury of multiple organs. To date, multiple studies have explored pathologic conditions in many vital organs, including lungs, liver, and kidneys. Although data suggest that sepsis is emerging as a key driver of chronic brain dysfunction, the immunological consequence of severe inflammatory responses in the brain remain poorly understood. In this study, we used C57BL/6 sepsis mouse models to establish a disease phenotype in which septic mice with various degrees of severity recover. In the early phases of sepsis, monocytes infiltrate the brain with significantly elevated proinflammatory cytokine levels. In recovered animals, monocytes return to vehicle levels, but the number of brain-resident microglia is significantly increased in the cortex, the majority of which remain activated. The increase in microglia number is mainly due to self-proliferation, which is completely abolished in CCR2 knockout mice. Collectively our data suggest that early monocyte infiltration causes permanent changes to microglia during sepsis, which may ultimately dictate the outcome of future infections and neuropathological diseases.