Search Results (164)

Diabetic retinopathy (DR), a major complication of diabetes, is driven by chronic inflammation in which retinal microglial cells play a central role. The Hippo pathway kinases NDR1/2 regulate macrophage function, but their role in microglia and DR remain unknown. This study investigates the function of the NDR2 kinase in microglial cells under high-glucose (HG) conditions. Using CRISPR-Cas9, we partially knocked out the Ndr2/Stk38l gene in BV-2 mouse microglial cells and analyzed metabolic activity, phagocytosis, migration, and cytokine release. We confirmed NDR2 expression in microglia and observed increased levels under HG, suggesting a role in hyperglycemia-induced stress. Ndr2/Stk38l (hereafter referred to as Ndr2) downregulation impaired mitochondrial respiration and reduced metabolic flexibility, indicating defective stress adaptation. Functionally, microglia with a partial downregulation of Ndr2 displayed reduced phagocytic and migratory capacity—both dependent on cytoskeletal dynamics. Moreover, Ndr2 downregulation altered the secretory profile, elevating pro-inflammatory cytokines (IL-6, TNF, IL-17, IL-12p70) even under normal glucose levels. These findings identify NDR2 protein kinase as a key regulator of microglial metabolism and inflammatory behavior under diabetic conditions. By modulating immune and metabolic responses, NDR2 may contribute to the neuroinflammatory processes underlying DR. Targeting NDR2 function in microglia may offer novel therapeutic strategies to mitigate retinal inflammation and progression of DR. Full article

Background: Prolonged hypoxia contributes to irreversible organ damage, particularly in the brain and heart. While chronic hypoxia is harmful, mild short-term hypoxia can trigger protective mechanisms. This study investigates how such hypoxic conditions affect BV-2 tolerant microglial cells in vitro, focusing on inflammation, metabolism, and functional activity. Although in vitro models provide a controlled setting, our findings may offer insights into microglial behavior in vivo under similar conditions. Methods: We used various molecular and biochemical techniques to assess the inflammatory state of BV-2 microglia under hypoxia, measuring glycolytic activity (via lactate production), and evaluating migratory and phagocytic capacities in vitro. Results: Hypoxic conditions induced a more tolerant, anti-inflammatory phenotype in BV-2 cells, with decreased pro-inflammatory mediators and reduced glycolytic activity, regulated by the MyD88/NF-κB p65 pathway. Tolerance supports increased migration and phagocytosis, but under hypoxic conditions, these effects were significantly declined compared to normoxic conditions, mediated through the ERK1/2 pathway. Conclusions: These findings suggest that short-term hypoxia may regulate microglial behavior and restore homeostasis, with implications for neuroinflammatory conditions. Full article

This study aimed to screen and identify a novel immune-enhancing peptide and explore the molecular mechanism. Five novel peptides were identified from Agaricus blazei Murrill (ABM), and their secondary structure components consisted of random coil (50.5%), α-helix (28.9%), β-turn (15.6%), and β-sheet (5.0%). A novel peptide (LNEDELRDA) with a molecular weight of 1074.0989 Da could bind with PI3K, AKT, mTOR, IL-6, IL-1β, and TNF-α through hydrogen bonding interactions, and the binding energies were −8.1, −8.3, −7.2, −6.0, −7.4, and −5.8 kcal/mol, respectively. This peptide was synthesized and validated for immune-enhancing ability, showing the strongest immune-enhancing capacity by increasing the cell viability and phagocytic activity of RAW 264.7 macrophages, significantly promoting the production of NO, cytokines TNF-α, IL-1β, and IL-6 in cells, and up-regulating the mRNA and protein expression levels of the PI3K/AKT/mTOR signaling pathway. Our results are the first to reveal that ABM-derived peptide LNEDELRDA could be considered as a promising food-borne immunomodulator that could contribute to enhancing immune function. Full article

This study investigated the protective effects of Gardenia jasminoides Ellis polysaccharides (GP) on lipopolysaccharide (LPS)-induced immunosuppression and oxidative stress in mice and explored how GP modulates macrophage polarization through the TLR4/NF-κB signaling axis. The results showed that GP notably restored thymus and spleen indices in LPS-treated mice, markedly decreased the serum concentrations of malondialdehyde, and enhanced superoxide dismutase activity and total antioxidant capacity. In RAW 264.7 macrophage cultures, GP displayed immunostimulatory effects by improving phagocytic activity, promoting NO synthesis, and enhancing the secretion of pro-inflammatory cytokines, including IL-1β, IL-6, and TNF-α. These effects were observed in cells not pretreated with TAK-242 or PDTC; however, they were not observed in cells pretreated with these inhibitors. At 300 µg/mL concentration, GP markedly enhanced the transcriptional levels of iNOS and cytokine genes. Protein analysis revealed significant upregulation of TLR4, MyD88, TRAF6, NF-κB RelA/p65, and phosphorylated p65. Fluorescence imaging confirmed the nuclear translocation of p65. Collectively, these findings indicated that GP reversed systemic immunosuppression and oxidative stress, offering foundational insights for developing natural immune regulators. The observed immunomodulatory properties of GP are likely mediated through the TLR4/NF-κB signaling pathway. Full article

Egg yolk IgY antibody has significant application potential in aquaculture as a form of passive immunotherapy against various bacterial infections owing to its capacity for large-scale and cost-effective production. In this research, laying hens were immunized with live or inactivated Aeromonas hydrophila to produce IgY antibodies. Following this, experiments were carried out to assess the passive immune protection rates of the two types of IgY antibodies when used to immunize goldfish (Carassius auratus), which were then infected with A. hydrophila or Aeromonas veronii. ELISA experiments were conducted to demonstrate the interaction between the IgY antibodies and the bacteria. The kidneys of C. auratus were coated on a Luria–Bertani (LB) medium to evaluate bacterial content. The leukocyte phagocytosis was detected by a cell phagocytosis assay. The serum of C. auratus was used to assess the expression of antioxidant factors, and a qRT-PCR was conducted to evaluate the mRNA expression of inflammatory factors in visceral tissue. Furthermore, histopathology and immunofluorescence analysis were performed to evaluate the structural integrity, apoptosis, and DNA damage of visceral tissues. The results indicated that the live or inactivated A. hydrophila IgY antibodies exhibited passive immune protection rates against A. hydrophila and A. veronii and could recognize these two bacteria in vitro. Additionally, these two IgY improved the phagocytic ability of leukocytes, diminished renal bacterial concentration, and decreased the levels of antioxidant factors and mRNA expression of inflammatory factors. Meanwhile, the two IgY antibodies did not cause any pathology of the kidney, spleen, and intestine, and decreased the levels of DNA damage factor (γH2A.X) and cell apoptosis factor (p53) in renal tissue. Therefore, live and inactivated A. hydrophila IgY antibodies can resist bacterial infections, with live bacteria IgY providing greater protection than inactivated bacteria IgY. Further, A. hydrophila is an aquatic pathogen that causes minimal damage to laying hens, and the immunity of live A. hydrophila conforms to animal welfare. Altogether, live A. hydrophila IgY antibody can serve as a polyvalent passive immune vaccine candidate in aquaculture. Full article

Neurodegenerative diseases are characterized by progressive loss of neurons and remain largely incurable. Numerous mammalian models have been developed to study the mechanisms underlying their physiopathology; however, their high cost, complexity and time requirements highlight the need for alternative systems. Glial cells are increasingly recognized as key contributors to neurodegenerative disease progression through non-cell autonomous mechanisms. Planarians possess a nervous system with diverse neuronal subtypes and glial cells, offering an attractive combination of evolutionary conservation and remarkable regenerative capacity. Unlike mammalian glia, planarian glia originate from phagocytic progenitors and exhibit distinctive molecular markers, including if-1, cali and cathepsin. Emerging evidence suggests that planarian glia may contribute to neurotransmitter homeostasis, neuron–glia interactions and phagocytic activity. Additionally, planarians display robust and quantifiable behavioral responses, making them well suited for modeling neurodegenerative disease. In this review, we summarize the current findings regarding neuronal subtypes and glial cells in planaria, emphasizing their relevance as a model system. Further research into planarian glia will be crucial for understanding their roles in pathological contexts and for exploring their potential applications in neurodegenerative diseases research. Planarian simplicity, regenerative capacity, and compatibility with high-throughput approaches position planarians as a powerful model for investigating the cellular and molecular mechanisms underlying neurodegenerative diseases and for identifying potential therapeutic targets. Full article

Background/Objectives: Macrophages with the M2 phenotype are an immune population with great relevance for tumor development. We have previously demonstrated that mesenchymal stromal cells (MSCs) from cervical cancer (CeCa-MSCs) enhance the immunomodulatory activity of CeCa cells on T lymphocytes; however, the effect of these cells on the ability of tumor cells to polarize macrophages had not been evaluated to date. Methods: To address this, we set out to analyze the effect of normal cervix (NCx) and CeCa-MSCs interacting with CeCa tumor cells (TCs) to polarize macrophages in a coculture system. Results: Our results show that macrophages from TC/NCx-MSC cocultures decreased CD163 expression. In turn, we observed that macrophages from TC/CeCa-MSC cocultures, in contrast to those in the presence of TCs/NCx-MSCs, increased the intracellular production of IDO, IL-4, and IL-10; decreased T lymphocyte proliferation; and increased the presence of soluble IL-10. Interestingly, coculture in the presence of TCs/NCx-MSCs decreased the capacity of macrophages to generate regulatory T lymphocyte populations, as well as their phagocytic capacity, and increased IL-6 secretion, unlike the coculture of macrophages in the presence of TCs/CeCa-MSCs. Our results show that TCs/CeCa-MSCs in cocultures, unlike TCs/NCx-MSCs, have a greater capacity to polarize macrophages to an M2 phenotype and that such macrophages have a greater immunosuppressive potential. Conclusions: This in vitro study suggests that intracellular communication between MSCs and tumor cells in CeCa may promote tumor growth through the polarization of macrophages with increased immunosuppressive activity. Full article

The sea cucumber (Apostichopus japonicus) is a commercially important marine species. However, its survival is increasingly threatened by frequent outbreaks of Skin Ulceration Syndrome caused by Vibrio splendidus. This study evaluated the effects of dietary supplementation with ferrous sulfate (FeSO₄) at two concentrations (0.5% and 1%) over short-term (21 days) and long-term (56 days) feeding periods on immune defense, antioxidant capacity, and resistance to V. splendidus infection. Key parameters measured included survival rate, cellular immune activity, antioxidant enzyme levels, and expression of immune-related genes. Long-term (56 days) supplementation with 1% FeSO₄ significantly improved survival after infection (90 ± 4.7%). Phagocytic activity and respiratory burst were enhanced by approximately ~1.9-fold and ~1.8-fold, respectively (p < 0.05). The expression of sod, ferritin, and hsp70 genes was upregulated by ~2.1-fold, ~2.0-fold, and ~1.6-fold, respectively (p < 0.05). These results indicate strengthened cellular immunity and antioxidant capacity. Long-term (56 days) supplementation with 0.5% FeSO₄ increased lysozyme activity (~1.3-fold) and c3 expression (~4-fold) (p < 0.05), thereby enhancing humoral immunity. In contrast, short-term (21 days) supplementation increased ACP and AKP activities by approximately ~2-fold each, and LZM activity by ~1.2-fold (p < 0.05). However, it did not significantly improve survival, indicating limited protective effects. Overall, 56-day dietary supplementation with FeSO₄, particularly at 1%, effectively enhances immune and antioxidant responses in A. japonicus. This supplementation represents a promising strategy for preventing V. splendidus-induced skin ulceration in aquaculture. Full article

Neonatal pneumonia, a leading cause of morbidity and mortality, is frequently caused by Group B Streptococcus (GBS). The mechanisms underlying protective immunity to this pathogen in the neonatal lung remain incompletely understood. Using a clinically relevant neonatal mouse model of GBS pneumonia, we investigated the immune mechanisms influencing disease severity. We demonstrate that neutrophils are effectively recruited to the lungs of infected neonates, but their phenotype differs with disease severity. In pups with moderate disease, we observe significant infiltration of SiglecF^hi neutrophils, a phenotype associated with enhanced phagocytic capacity and bacterial clearance. In contrast, pups with severe disease failed to develop SiglecF^hi neutrophils, resulting in reduced bacterial clearance and worsened pathology. We further show that severity is associated with increased expression of calcitonin gene-related peptide (CGRP) in the lungs. CGRP suppressed neutrophil activation into the SiglecF^hi phenotype, thereby limiting their antibacterial function. Our findings show that GBS exploits the neuroimmune axis to evade host immunity through CGRP-mediated suppression of neutrophil activation. Full article

Egg yolk immunoglobulin Y (IgY) has significant application potential in aquaculture as passive immunotherapy against various bacterial infections owing to its capacity for large-scale and cost-effective production. In this study, IgY antibodies of live or inactivated Aeromonas veronii were generated by laying hens immunization. Subsequently, passive immune protection experiments of the two IgY antibodies were conducted on goldfish (Carassius auratus) infected with A. veronii and Aeromonas hydrophila. The results indicated that both live and inactivated bacteria IgY antibodies provided significant passive protection rates (p < 0.05). Furthermore, ELISA tests demonstrated that the two IgY antibodies, as well as the serum of C. auratus, interacted with A. veronii or A. hydrophila (p < 0.05) in vitro. The bacterial loads in the kidneys of C. auratus immunized with the two IgY antibodies were decreased (p < 0.05), and C. auratus phagocytes had enhanced phagocytic activity. The expression levels of antioxidant factors (SOD, CAT, GSH-Px) and inflammatory factors mRNA (TNF-α, IL-1β, IL-6, IL-8) were down-regulated (p < 0.05). Additionally, histopathological analysis indicated that the renal, splenic, and intestinal tissue structures remained intact, and the immunofluorescence confirmed that apoptosis and DNA damage factors of p53 and γH2A.X reduced (p < 0.05), respectively. Thus, the IgY antibodies of live and inactivated A. veronii exhibit passive immune-protective effects against different pathogenic bacteria in C. auratus. Further, inactivated A. veronii immunization causes less damage to laying hens than that of live bacteria, which aligns more closely with welfare standards for laying hens, and the IgY of inactivated A. veronii is anticipated as a cross-protection against A. veronii and A. hydrophila infections in aquaculture. Full article

Microglia are resident phagocytes of the central nervous system that play an essential role in brain development and homeostasis. When the intracellular lipid content exceeds the metabolic capacity of microglia, lipid droplets accumulate, giving rise to a distinct population termed lipid-laden microglia (LLMs). LLMs have been implicated in various neuroinflammatory and neurodegenerative diseases, functioning as both regulators/indicators of inflammation and potential therapeutic targets. This review summarizes the current research on LLMs, focusing on disease-specific regulators and functions, protective roles, interactions with neighboring cells, and advances in diagnostic and analytical tools. We also discuss the blurred distinction between LLMs and macrophages, inconsistent terminology, and major knowledge gaps across different disease contexts. Deciphering the composition, formation, and dynamics of lipid droplets in microglia is critical for uncovering how microglial states shift under diverse pathological stimuli. A clearer view of these mechanisms may reveal novel roles of LLMs and open new avenues for therapeutic intervention. Full article

Studies on plant extracts as growth promoters and immunostimulants have shown promising results. However, their effects on fish health and growth remain unclear. This study evaluated the in vitro and in vivo effects of Eucalyptus globulus pyroligneous extract (PE) on Nile tilapia. In vitro, minimal inhibitory and bactericidal concentration (MIC and MBC) and antibiogram analyses showed that PE could eliminate key bacterial strains affecting fish and human health, but only if its volatile components were preserved. In vivo, Oreochromis niloticus juveniles were fed diets containing 0.5% and 1% PE. We assessed fish hematology, phagocytosis, survival against Streptococcus agalactiae, and growth parameters. Fish fed 1% PE had lower erythrocyte and lymphocyte counts but higher neutrophil levels than controls. Their phagocytic capacity was significantly enhanced compared to both the control and 0.5% groups. However, the 0.5% PE group had a higher phagocytic index than both the control and 1% groups. No protection against S. agalactiae or significant effects on growth were observed. In conclusion, distilled E. globulus PE shows potential as an immunostimulant for fish. However, further studies are needed to preserve its volatile compounds and optimize its use in aquaculture. Full article

The immunomodulatory polysaccharide CPP-3a, purified from Chlorella pyrenoidosa, was investigated for its effects on RAW264.7 macrophages and underlying mechanisms, revealing that CPP-3a significantly enhanced phagocytic capacity and nitric oxide production while upregulating pro-inflammatory cytokines TNF-α and IL-6 and elevating the co-stimulatory molecule CD86, collectively driving robust M1 polarization. Mechanistically, TLR4-, TLR2-specific inhibitors, and TLR4-knockout cells confirmed TLR4 as the primary receptor for CPP-3a, with TLR2 playing a secondary role in cytokine modulation. CPP-3a activated NF-κB and p38 MAPK signaling pathways via the MyD88-dependent pathway, evidenced by phosphorylation of NF-κB/p65 with its nuclear translocation and increased phosphorylation of p38 MAPK, with these signaling activations further validated by specific pathway inhibitors that abolished M1 polarization phenotypes. Collectively, CPP-3a emerges as a potent TLR4-targeted immunomodulator with adjuvant potential for inflammatory and infectious diseases. Full article

Glioblastoma is a highly aggressive brain tumor with an overall poor prognosis due to its immunosuppressive tumor microenvironment (TME). Microglia and tumor-associated macrophages (TAMs) with pro-tumorigenic properties are dominant populations of immune cells in the glioblastoma TME. To date, several studies targeting TAMs to fight tumor progression in different tumor entities have been initiated. However, the impact of standard therapy schemes of glioblastoma cells on macrophage polarization, activation, and phagocytosis remains controversial. The same applies to the relevance of PD-1/PD-L1 blockade in the interaction between macrophages and tumor cells. Our study, therefore, investigated patient-oriented treatment of GLIOBLASTOMA by examining the phagocytic capacity of polarized M1- and M2-like macrophages using GL261-luc2 tumor cells as a preclinical model system. Additionally, we analyzed the expression of activation and immune checkpoint markers on these macrophage subtypes following contact with tumor cells and their microenvironment. These factors were also determined after PD-1 blockade was initiated. The analyses revealed that the immunoregulatory M2-like macrophages generally exhibited a higher phagocytosis rate than the pro-inflammatory M1-like macrophages; however, this was not influenced by the pretreatment of glioblastoma cells with chemo- or radiotherapy. This could not be improved by blocking the PD-1 receptor. Furthermore, there were no modulations in the expression of differentiation, activation, or immune checkpoint molecules of M1- and M2-like macrophages after cell-to-cell contact with glioblastoma cells. But the medium conditioned by tumor cells strongly altered M1-like macrophages toward a more activated state, whereas M2-like cells were only mildly influenced. This was further enhanced by tumor cell treatment, with the most prominent effect after irradiation. These results suggest that conventional GLIOBLASTOMA tumor cell treatment affects the immunogenic status of macrophage subtypes, which is relevant for enhancing the anti-tumor immune response in brain tumors. Full article

Peripheral blood leukocytes are able to migrate to the inflamed tissue, and to engulf and kill invading microbes. This requires rapid modifications of cell morphology and volume through fast movements of osmotic water into or out of the cell. In this process, membrane water channels, aquaporins (AQPs), are critical for cell shape changes as AQP-mediated water movement indirectly affects the cell cytoskeleton and, thereby, the signaling cascades. Recent studies have shown that the deletion or gating of two immune cell AQPs, AQP3 and AQP9, impairs inflammation and improves survival in microbial sepsis. Here, we assessed the expression and distribution of AQP3 and AQP9 in human leukocytes and investigated their involvement in the phagocytosis and killing of the Gram-negative pathogenic bacterium Klebsiella pneumoniae, and their role in lipopolysaccharide (LPS)-induced cell migration. By RT-qPCR, AQP3 mRNA was found in peripheral blood mononuclear cells (PBMCs) but it was undetectable in polymorphonuclear white blood cells (PMNs). AQP9 was found both in PBMCs and PMNs, particularly in neutrophil granulocytes. Immunofluorescence confirmed the AQP3 expression in monocytes and, to a lesser degree, in lymphocytes. AQP9 was expressed both in PBMCs and neutrophils. Specific inhibitors of AQP3 (DFP00173) and AQP9 (HTS13286 and RG100204) were used for bacterial phagocytosis and killing studies. No apparent involvement of individually blocked AQP3 or AQP9 was observed in the phagocytosis of K. pneumoniae by neutrophils or monocytes after 10, 30, or 60 min of bacterial infection. A significant impairment in the phagocytic capacity of monocytes but not neutrophils was observed only when both AQPs were inhibited simultaneously and when the infection lasted for 60 min. No impairment in bacterial clearance was found when AQP3 and AQP9 were individually or simultaneously blocked. PBMC migration was significantly impaired after exposure to the AQP9 blocker RG100204 in the presence or absence of LPS. The AQP3 inhibitor DFP00173 reduced PBMC migration only under LPS exposure. Neutrophil migration was considerably reduced in the presence of RG100204 regardless of whether there was an LPS challenge or not. Taken together, these results indicate critical but distinct involvements for AQP3 and AQP9 in leukocyte motility, while no roles are played in bacterial killing. Further studies are needed in order to understand the precise ways in which these two AQPs intervene during bacterial infections. Full article