Search Results (106)

The cells in the central nervous system (CNS) can adapt to injury and inflammation through structural and functional changes, many of which are mediated by the kynurenine pathway (KP). Studies using glia–neuron co-cultures showed that the biflavonoid agathisflavone (FAB), purified from the leaves of Cenostigma pyramidale Tul., a plant native to the Brazilian caatinga, exerts strong neuroprotective effects. This study evaluated whether agathisflavone (1 µM) modulates these responses in human and murine astrocytes and microglia exposed to inflammatory activation with lipopolysaccharide (LPS, 1 µg/mL), excitotoxic activation of NMDA receptors with quinolinic acid (QUIN, 500 µM), or inhibition of the KP rate-limiting enzyme indoleamine 2,3-dioxygenase 1 (IDO1) with 1-methyl tryptophan (1-MT, 1.5 μM). Co-treatment with FAB increased astrocyte viability relative to LPS, QUIN, or 1-MT alone, by up to 35% (p < 0.05), while reducing GFAP overexpression and other features of reactive astrogliosis. FAB decreased the proportion of Iba-1⁺ microglia, indicating anti-inflammatory effects. When combined with QUIN or 1-MT, FAB reversed the elevation of iNOS (p < 0.0001) and reduced IL1β upregulation. FAB also modulated KP activity in a cell type-specific manner. In astrocytes, FAB with QUIN or with 1-MT increased IDO activity, whereas in microglia, FAB alone reduced it. In microglia, kynurenine-3-monooxygenase (KMO) expression was significantly increased under FAB+QUIN or FAB+1-MT (p < 0.0001). Finally, astrocyte-conditioned medium from FAB-treated cells increased the viability of neuron-like PC12 cells by up to 40%. Collectively, these findings show that FAB confers cytoprotective and anti-inflammatory actions on glial cells, modulates KP signalling in a context-dependent manner, and supports neuronal survival under neuroinflammatory conditions. Full article

Minocycline (MINO), a classic antibiotic, may have psychotropic activity related to the modulation of the tryptophan-kynurenine pathway. In this study, we investigated the effects of MINO on (1) memory and anxiety behaviors, (2) the modulation of brain levels of amyloid precursor protein (APP) and 2,3-indoleamine dioxygenase (IDO1) levels, and (3) peripheral inflammatory markers in a streptozotocin (STZ)-induced rat model of sporadic Alzheimer’s disease (sAD). After repeated treatment with a dose of 35 mg/kg MINO for seven consecutive days, male Wistar rats with sAD showed (1) improvements in early (29 days after injection, probe test) reference memory (decreased latency to reach the platform, increased time in the critical quadrant of the Morris water maze) and anxiety disorders (increased time in the open arms of the elevated plus maze; increased exploration and entrances in the center of the white–light illuminated open field) 45–46 and 90–91 days after STZ injection; (2) reduced APP and IDO1 levels in the hippocampus and prefrontal cortex; and (3) induction of anti-inflammatory response in blood (increased TCD4⁺ lymphocyte number and interleukin-10 production). This suggests that MINO, due to its anti-inflammatory action, improves memory and anxiety behavior related to sAD, indicating its neuroprotective and psychotropic properties. Full article

Background: The liver’s role as a metabolic gatekeeper positions it uniquely to influence systemic metabolic homeostasis and potentially modulate leukemogenesis through hepato-hematopoietic crosstalk. Recent observations of rare hematological malignancies following mRNA vaccination warrant mechanistic investigation. Hypothesis: We propose that mRNA vaccines, through their preferential hepatic tropism via lipid nanoparticles (LNPs), may transiently dysregulate hepatic metabolism in susceptible individuals, creating metabolic perturbations that amplify pre-existing leukemogenic vulnerabilities through five interconnected mechanisms: (1) competitive folate sequestration for vaccine-induced lymphoproliferation, potentially starving bone marrow precursors of essential one-carbon units; (2) hepatic lipid processing overload from LNP accumulation, exacerbating phospholipid dysregulation in pre-leukemic clones; (3) cytokine-mediated upregulation of hepatic indoleamine 2,3-dioxygenase (IDO), accelerating tryptophan catabolism and creating an immunosuppressive milieu favoring leukemic escape; (4) inflammatory induction of hepcidin, sequestering hepatic iron while triggering compensatory intestinal iron hyperabsorption and potential bone marrow iron overload; and (5) increased hepatic NADPH demand for antioxidant defense and lipid metabolism, diverting reducing equivalents from bone marrow stromal support. Implications: This hypothesis suggests that transient hepatic metabolic perturbations may create a permissive milieu for leukemogenesis in metabolically vulnerable individuals. The proposed mechanisms generate testable predictions and identify potential therapeutic targets, including folate supplementation, IDO inhibition, and iron chelation in high-risk cohorts. Full article

The kynurenine (KYN) metabolic pathway sits at the crossroads of immunity, metabolism, and neurobiology, yet its clinical translation remains fragmented. Emerging spatial omics, wearable chronobiology, and synthetic microbiota studies reveal that tryptophan (Trp) metabolism is regulated by distinct cellular “checkpoints” along the gut–brain axis, finely modulated by sex differences, circadian rhythms, and microbiome composition. However, current interventions tackle single levers in isolation, leaving a key gap in the precision control of Trp’s fate. To address this, we drew upon an extensive body of the primary literature and databases, mapping enzyme expression across tissues at single-cell resolution and linking these profiles to clinical trials investigating dual indoleamine 2,3-dioxygenase 1 (IDO1)/tryptophan 2,3-dioxygenase (TDO) inhibitors, engineered probiotics, and chrono-modulated dosing strategies. We then developed decision-tree algorithms that rank therapeutic combinations against biomarker feedback loops derived from real-time saliva, plasma, and stool metabolomics. This synthesis pinpoints microglial and endothelial KYN hotspots, quantifies sex-specific chronotherapeutic windows, and identifies engineered Bifidobacterium consortia and dual inhibitors as synergistic nodes capable of reducing immunosuppressive KYN while preserving neuroprotective kynurenic acid. Here, we highlight a framework that couples lifestyle levers, bio-engineered microbes, and adaptive pharmaco-regimens into closed-loop “smart protocols.” By charting these intersections, this study offers a roadmap for biomarker-guided, multidisciplinary interventions that could recalibrate KYN metabolic activity across cancer, mood, neurodegeneration, and metabolic disorders, appealing to clinicians, bioengineers, and systems biologists alike. Full article

Skeletal muscle atrophy is a critical health issue affecting the quality of life of elderly individuals and patients with chronic diseases. These conditions induce dysregulation of glucocorticoid (GC) secretion. GCs play a critical role in maintaining homeostasis in the stress response and glucose metabolism. However, prolonged exposure to GC is directly linked to muscle atrophy, which is characterized by a reduction in muscle size and weight, particularly affecting fast-twitch muscle fibers. The GC-activated glucocorticoid receptor (GR) decreases protein synthesis and facilitates protein breakdown. Numerous antagonists have been developed to mitigate GC-induced muscle atrophy, including 11β-HSD1 inhibitors and myostatin and activin receptor blockers. However, the clinical trial results have fallen short of the expected efficacy. Recently, several emerging pathways and targets have been identified. For instance, GC-induced sirtuin 6 isoform (SIRT6) expression suppresses AKT/mTORC1 signaling. Lysine-specific demethylase 1 (LSD1) cooperates with the GR for the transcription of atrogenes. The kynurenine pathway and indoleamine 2,3-dioxygenase 1 (IDO-1) also play crucial roles in protein synthesis and energy production in skeletal muscle. Therefore, a deeper understanding of the complexities of GR transactivation and transrepression will provide new strategies for the discovery of novel drugs to overcome the detrimental effects of GCs on muscle tissues. Full article

Indoleamine 2,3-dioxygenase 1 (IDO-1) and interferon-gamma (IFN-γ) are proteins that play a significant role in inflammatory conditions and tumor development. The detection of IDO1 and IFN-γ is crucial for understanding their interplay in immune responses. This study introduced a novel method for the simultaneous quantitative determination of IDO-1 and IFN-γ in different biological samples/materials. The method is based on an optical biosensor, with surface plasmon resonance detection carried out by the imaging version of the sensor (SPRi). Biotinylated antibodies immobilized on the surfaces of the linker and carboxymethylated dextran served as the recognition elements for the developed biosensor. Relevant studies were conducted to optimize the activities of the biosensor by employing appropriate reagent concentrations. Validation was performed for each protein separately; low detection and quantification limits were obtained (for IDO-1 LOD = 0.27 ng/mL, LOQ = 0.81 ng/mL; for IFN-γ LOD = 1.76 pg/mL and LOQ = 5.29 pg/mL). The sensor operating ranges were 0.001–10 ng/mL for IDO-1 and 0.1–1000 pg/mL for IFN-γ. The constructed biosensor demonstrated its sensitivity and precision when the appropriate analytical parameters were determined, based on the proposed method. It can also selectively capture IDO-1 and IFN-γ from a large sample matrix. The biosensor efficiency was confirmed by the determination of IDO-1 and IFN-γ in simultaneous measurements of the plasma and urine samples of patients diagnosed with bladder cancer and the control group. The outcomes were compared to those obtained using a certified ELISA test, demonstrating convergence between the two methodologies. The preliminary findings demonstrate the biosensor’s efficacy and suitability for comprehensive analyses of the examined biological samples. Full article

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of immune cells that play a central role in regulating host immune responses during fungal infections. Their recruitment is mediated by pathogen recognition receptors, particularly Dectin-1 and CARD9 signaling, which promote the production of reactive oxygen species (ROS) and IL-1β. Once activated, MDSCs suppress T-cell and natural killer cell functions through immunosuppressive cytokines like IL-10 and TGF-β, as well as enzymes such as arginase-1 and indoleamine 2,3-dioxygenase 1 (IDO-1). This review explores the role of MDSCs in fungal infections caused by Candida spp., Paracoccidioides brasiliensis, Aspergillus spp., and Cryptococcus neoformans, emphasizing their impact on immune modulation and disease progression. The emerging evidence suggests that fungal bioactive compounds, such as polysaccharides, can influence MDSC activity and restore immune balance. Notably, therapies targeting MDSCs have demonstrated promise in both fungal infections. In particular, infections with P. brasiliensis and C. neoformans show improved T-cell responses following MDSC-targeted interventions. Additionally, polysaccharides from Grifola frondosa and exposure to Aspergillus sydowii affect MDSC behavior, supporting the potential of modulating these cells therapeutically. Together, these findings highlight the relevance of MDSCs in fungal pathogenesis and underscore their potential as targets for immunotherapeutic strategies in infectious diseases. Full article

Machine learning (ML) algorithms hold the potential to outperform the selection of patients for immunotherapy (ICIs) compared to previous biomarker studies. We analyzed the predictive performance of ML models and compared them to traditional clinical biomarkers (TCBs) in the field of gastrointestinal (GI) cancers. The study has been registered in PROSPERO (number: CRD42023465917). A systematic search of PubMed was conducted to identify studies applying different ML algorithms to GI cancer patients treated with ICIs using tumor RNA gene expression profiles. The outcomes included were response to immunotherapy (ITR) or survival. Additionally, we compared the ML methodology details and predictive power inherent in the published gene sets using 5-fold cross-validation and logistic regression (LR), on an available well-defined ICI-treated metastatic gastric cancer (GC) cohort (n = 45). A set of standard clinical ICI biomarkers (MLH, MSH, and CD8 genes, plus PMS2 and PD-L1)) and de-novo calculated principal components (PCs) of the original datasets were also included as additional points of comparison. Nine articles were identified as eligible to meet the inclusion criteria. Three were pan-cancer studies, five assessed GC, and one studied colorectal cancer (CRC). Classification and regression models were used to predict ICI efficacy. Next, using LR, we validated the predictive power of applied ML algorithms on RNA signatures, using their reported receiver operating characteristics (ROC) analysis area under the curve (AUC) values on a well-defined ICI-treated gastric cancer (GC) dataset (n = 45). In two cases our method has outperformed the published results (reported/LR comparison: 0.74/0.831, 0.67/0.735). Besides the published studies, we have included two benchmarks: a set of TCBs and using principal components based on the whole dataset (PCA, 99% explained variance, 40 components). Interestingly, a study using a selected gene set (immuno-oncology panel) with AUC = 0.83 was the only one that outperformed the TCB (AUC = 0.8) and the PCA (AUC =0.81) results. Cross-validation of the predictive performance of these genes on the same GC dataset and an investigation of their prognostic role on a collated multi-cohort GC dataset of n = 375 resected, or chemotherapy-treated patients revealed that genes mannose-6-phosphate receptor (M6PR), Indoleamine 2,3-Dioxygenase 1 (IDO1), Neuropilin-1 (NRP1), and MAGEA3 performed similarly, or better than established biomarkers like PD-L1 and MSI. We found an immuno-oncology panel with an AUC = 0.83 that outperformed the clinical benchmark or the PC results. We recommend further investigation and experimental validation in the case of M6PR, IDO1, NRP1, and MAGEA3 expressions based on their strong predictive power in GC ITR. Well-designed studies with larger sample sizes and nonlinear ML models might help improve biomarker selections. Full article

In order to take advantage of both immunotherapeutic and epigenetic antitumor agents, a series of imidazothiazole-based hydroxamic acid derivatives were designed based on the pharmacophore fusion strategy and evaluated as potent IDO1 and HDAC6 dual inhibitors. Among these inhibitors, the most potent compound 3-(4-Bromophenyl)-N-{4-[(7-(hydroxyamino)-7-oxoheptyl)amino]phenyl}imidazo[2,1-b]thiazole-5-carboxamide (10e) showed considerable IDO1 inhibitory activity and a good selectivity profile for HDAC6 over the other HDAC isoforms. The intracellular inhibition of HDAC6 by 10e was validated by Western blot analysis. Docking studies illustrated that the possible binding modes of compound 10e interacted with IDO1 and HDAC6. Moreover, compound 10e was found to arrest the cell cycle at the G2/M phase in HCT-116 cells. In particular, compound 10e also exhibited potent in vivo antitumor efficacy in CT26 tumor-bearing BALB/c mice models, with no significant toxicity. Collectively, this work provides a promising lead compound that serves as IDO1/HDAC6 dual inhibitor for the development of novel antitumor agents. Full article

Background and Objectives: Acute ulcerative colitis is characterized by excessive mucosal inflammation and epithelial disruption, often driven by dysregulated cytokine and immune signaling. Indoximod (1-methyl-DL-tryptophan), although not a direct enzymatic inhibitor, modulates the indoleamine 2,3-dioxygenase (IDO) pathway and has been reported to exert immunoregulatory effects in various models of inflammation. This study aimed to evaluate the protective effects of Indoximod in an acetic acid-induced colitis model in rats, focusing on histopathological changes and inflammatory mediators. Materials and Methods: Thirty male Wistar albino rats were randomly assigned to three groups (n = 10 per group): Group 1 (Control) received 0.9% saline oral gavage; Group 2 (Colitis) received intrarectal 4% acetic acid to induce colitis and were then treated with saline; Group 3 (Colitis + Indoximod) received 4% acetic acid followed by oral gavage administration of Indoximod (30 mg/kg) for 15 consecutive days. Histopathological evaluation of colonic tissues was performed using hematoxylin and eosin (H&E) staining. Colonic expression of Toll-like receptor 4 (TLR4) and plasma levels of tumor necrosis factor-alpha (TNF-α), pentraxin-3 (PTX-3), and platelet-activating factor (PAF) were quantified using enzyme-linked immunosorbent assay (ELISA). Results: Acetic acid-induced colitis significantly increased mucosal damage, TLR4 expression, and circulating levels of TNF-α, PTX-3, and PAF compared with controls (p < 0.001). Indoximod treatment markedly reduced histological injury and significantly suppressed TLR4 and TNF-α levels (p < 0.01), along with partial reductions in PTX-3 (p < 0.05). However, PAF levels remained elevated despite treatment, indicating limited efficacy in PAF-associated pathways. Conclusions: Indoximod exhibited anti-inflammatory effects in this acute colitis model, likely by downregulating key proinflammatory mediators. Full article

Mesenchymal stromal cells (MSCs) influence tumor biology and immunology by releasing cytokines, chemokines and growth factors. Currently, cisplatin is an integral part of drug-based tumor therapy, for example, in head and neck squamous cell carcinoma (HNSCC). Cisplatin treatment induces apoptosis as a primary mechanism of action; however, additional immunomodulatory effects of cisplatin are gaining interest. The aim of this study is to evaluate the possible immunomodulatory effects of cisplatin in human MSCs (hMSCs). The MSCs, obtained from human bone marrow, were characterized by analyzing plastic adherence, typical surface features, and ability to differentiate. Toxicity analysis of cisplatin’s effects on primary MSCs, including the determination of a subtoxic concentration, was performed using the MTT assay. Enzyme-linked immunosorbent assays (ELISA) and a quantitative real-time polymerase chain reaction (qRT-PCR) were used to identify potentially immunomodulatory factors. Additionally, a scratch assay was performed to evaluate cell migration. First, subtoxic cisplatin concentrations were determined. A significantly reduced protein expression of indoleamine 2,3-dioxygenase 1 (IDO1) in MSCs under the influence of subtoxic cisplatin concentrations was demonstrated. Similarly, IL-6 protein expression was qualitatively reduced at subtoxic concentrations, although without statistical significance. At the mRNA level, qRT-PCR showed a non-significant, cisplatin concentration-dependent reduction in the expression of both IL-6 and IDO1. The scratch assay showed no statistically significant influence on migration after cisplatin treatment. In MSCs, there is tendency to a decrease in IL-6 and IDO1 at both protein and mRNA level after cisplatin exposure. These effects are congruent with each other and dose-dependent. This indicates that cisplatin not only acts via the known cytotoxic effect, but may induce a reduction in tumor-supporting proteins, like IL-6 and IDO1, by MSCs in the tumor microenvironment at subtoxic concentrations. Traditional cytostatic compounds, which can favorably modulate the immune system in the tumor microenvironment, may open new avenues to explore treatment strategies specifically targeting immunomodulation. Overall, the results indicate beneficial immunomodulation by cisplatin. Full article

Objectives: The aim was to simultaneously investigate inflammatory biomarkers, neopterin, the kynurenine/tryptophan (Kyn/Trp) pathway, vitamin D (VitD), vitamin D binding protein (VDBP), and erythrocyte folate, in cerebral palsy (CP). Methods: A case–control study was conducted at Mersin University Hospital. Three- to ten-year-old patients with spastic CP (n = 50) and age- and gender-matched healthy controls (n = 55) were included. Serum levels of neopterin, Trp, Kyn and 25OHD, plasma VDBP, and erythrocyte folate concentrations were measured. Indoleamine-2,3-dioxygenase 1 (IDO-1) enzyme activity was evaluated according to the Kyn/Trp ratio. Comparison and correlation analyses were performed. Results: The levels of neopterin, Trp, and Kyn were lower in children with CP than in healthy controls (p = 0.037, p < 0.001, and p = 0.003, respectively). IDO1 was not significantly different between the CP and control groups (p = 0.214). The levels of VitD and VDBP were higher in children with CP (p < 0.001 and p = 0.001, respectively). The level of erythrocyte folate was also higher in children with CP (p < 0.001). No significant correlation was found between age and inflammatory biomarkers in the CP group. Neopterin was correlated with the level of Gross Motor Function Classification System (GMFCS) level (r = 0.292, p = 0.044), while there was no significant correlation between the other biomarkers and the level of GMFCS in the CP group. Conclusions: Inflammatory biomarkers of neopterin and Kyn are lower, inflammatory biomarkers of VDBP and erythrocyte folate are higher, and anti-inflammatory VitD is higher in children with spastic CP compared to healthy children. More knowledge is needed to demonstrate inflammatory and anti-inflammatory status in children with CP. Full article

Indoleamine 2,3-dioxygenase 1 (IDO1) and IDO2 originated from gene duplication before vertebrate divergence. While IDO1 has a well-defined role in immune regulation, the biological role of IDO2 remains unclear. Discovered in 2007, IDO2 is located near the IDO1 gene. Because of their high sequence similarity, IDO2 was initially thought to be a tryptophan (Trp)-degrading enzyme like IDO1. Differently from what expected, IDO2 displays extremely low catalytic activity toward Trp. Nevertheless, many studies, often contradictory, have tried to demonstrate that IDO2 modulates immune responses by catabolizing Trp into kynurenine, an unconvincing hypothesis linked to an incomplete understanding of IDO2’s activity. In this study, we review IDO2’s functional role beyond Trp metabolism. IDO2’s evolutionary persistence across species, despite being almost inactive as an enzyme, suggests it has some relevant biological importance. IDO2 expression in human normal cells is poor, but significant in various cancers, with two prevalent SNPs. Overall, the comparison of IDO2 to IDO1 as a Trp-degrading enzyme may have led to misunderstandings about IDO2’s true physiological and pathological roles. New insights suggest that IDO2 might function more as a signaling molecule, particularly in cancer contexts, and further studies could reveal its potential as a target for cancer therapy. Full article

Amelanotic melanoma (AM) is a subtype of hypomelanotic or completely amelanotic melanoma. AM is a rare subtype of melanoma that exhibits a higher recurrence rate and aggressiveness as well as worse surveillance than typical melanoma. AM shows a dysregulation of melanin production, cell cycle control, and apoptosis pathways. Knowing these pathways has an application in medicine due to targeted therapies based on the inhibiting elements of the abovementioned pathways. Therefore, we summarized and discussed AM biochemical and molecular induction pathways and personalized medicine approaches, clinical management, and future directions due to the fact that AM is relatively rare. AM is commonly misdiagnosed. Hence, the role of biomarkers is becoming significant. Nonetheless, there is a shortage of biomarkers specific to AM. BRAF, NRAS, and c-KIT genes are the main targets of therapy. However, the role of BRAF and KIT in AM varied among studies. BRAF inhibitors combined with MAK inhibitors demonstrate better results. Immune checkpoint inhibitors targeting CTLA-4 combined with a programmed death receptor 1 (PD-1) show better outcomes than separately. Fecal microbiota transplantation may overcome resistance to immune checkpoint therapy of AM. Immune-modulatory vaccines against indoleamine 2,3-dioxygenase (IDO) and PD ligand (PD-L1) combined with nivolumab may be efficient in melanoma treatment. Full article

Although therapies based on mesenchymal stromal cells (MSCs) are being implemented in clinical settings, many aspects regarding these procedures require further optimization. Domestic dogs suffer from numerous immune-mediated diseases similar to those found in humans. This study aimed to assess the immunomodulatory activity of canine (c) Wharton jelly (WJ)-derived MSCs and refer them to human (h) MSCs isolated from the same tissue. Canine MSC(WJ)s appeared to be more prone to in vitro aging than their human counterparts. Both canine and human MSC(WJ)s significantly inhibited the activation as well as proliferation of CD4+ and CD8+ T cells. The treatment with IFNγ significantly upregulated indoleamine-2,3-dioxygenase 1 (IDO1) synthesis in human and canine MSC(WJ)s, and the addition of poly(I:C), TLR3 ligand, synergized this effect in cells from both species. Unstimulated human and canine MSC(WJ)s released TGFβ at the same level (p > 0.05). IFNγ significantly increased the secretion of TGFβ in cells from both species (p < 0.05); however, this response was significantly stronger in human cells than in canine cells. Although the properties of canine and human MSC(WJ)s differ in detail, cells from both species inhibit the proliferation of activated T cells to a very similar degree and respond to pro-inflammatory stimulation by enhancing their anti-inflammatory activity. These results suggest that testing MSC transplantation in naturally occurring immune-mediated diseases in dogs may have high translational value for human clinical trials. Full article