Immediate administration of hTERT-MSCs-IDO1-EVs reduces hypoalbuminemia after spinal cord injury

Spinal cord injury (SCI) presents challenging and unpredictable neurological recovery. During inflammatory conditions, the amount of serum albumin and nutrition consumption decreases. Currently, it is proposed to measure serum albumin and glucose content in human or animal subjects to predict the recovery rate and the efficiency of treatments following SCI. In this study, the effect of extra-cellular vesicles (EVs) from immortalized human adipose tissue-derived mesenchymal stem cells (hTERT-MSCs) equipped with the ectopic expression of the human indoleamine 2,3-dioxygenase-1 (IDO1) gene on serum albumin and glucose levels was investigated. After pre-clearing steps of 72-hr conditioned media, small EVs (sEVs) were isolated based on the ultra-filtration method. They were encapsulated with a chitosan-based hydrogel. Five experimental groups (female rats, N = 30, ~ 230 g) were considered, including SCI, sham, hydrogel, control green fluorescent protein (GFP)-EVs and IDO1-EVs. The 60.00 µL of hydrogel or hydrogels containing 100 µg sEVs from GFP or IDO1-EVs were locally injected immediately after SCI (laminectomy of the T10 vertebra and clip compression). After 8 weeks, non-fasting serum glucose and albumin levels were measured. The results indicated that the level of serum albumin in the animals received IDO1-EVs (3.52 ± 0.04) was increased in comparison with the SCI group (3.00 ± 0.94). Also, these animals indicated higher glucose levels in their serum (250.17 ± 69.61) in comparison with SCI ones (214 ± 45.34). Although these changes were not statistically significant, they could be considered as evidence for the beneficial effects of IDO1-EVs administration in the context of SCI to reduce hypoalbuminemia and improve energy consumption. More detailed experiments are required to confirm these results.

Changes in Immune Activation During Pregnancy and the Postpartum Period in Treated HIV Infection

Background

Pregnant women with HIV (PWWH) have high postpartum morbidity and mortality from infections like tuberculosis. Immunologic changes during pregnancy and postpartum periods may contribute to these risks, particularly the immunoregulatory kynurenine pathway of tryptophan catabolism, which contributes to both HIV and tuberculosis pathogenesis and increases in the early postpartum period.

Methods

Women with HIV initiating antiretroviral therapy (ART) in the Uganda AIDS Rural Treatment Outcomes (UARTO) cohort who were pregnant at enrollment or became pregnant during observation were studied (n = 54). Plasma kynurenine/tryptophan (KT) ratio, soluble CD14 (sCD14), sCD163, sCD27, interferon-inducible protein 10 (IP-10), D-dimer, interleukin-6, and intestinal fatty-acid binding protein levels were assessed through the first year of ART and at 3-month intervals throughout pregnancy and 1 year postpartum. Biomarker changes were assessed with linear mixed models adjusted for ART duration. Hemoglobin concentration changes were used to estimate pregnancy-related changes in plasma volume.

Results

The median pre-ART CD4 count was 134. D-dimer increased through the third trimester before returning to baseline postpartum, while most other biomarkers declined significantly during pregnancy, beyond what would be expected from pregnancy-associated plasma volume expansion. IP-10 and sCD14 remained suppressed for at least 12 months postpartum. KT ratio was the only biomarker that increased above prepregnancy baseline postpartum (mean + 30%; P < .001) and remained higher than baseline for ≥9 months (P ≤ .045 for all time points).

Conclusions

Several immune activation markers decline during pregnancy and remain suppressed postpartum, but the kynurenine pathway of tryptophan catabolism increases above baseline for ≥9 months postpartum. The mechanisms underlying postpartum kynurenine pathway activity are incompletely understood but may contribute to increased tuberculosis risk in this setting.

The Gut Microbiota, Kynurenine Pathway, and Immune System Interaction in the Development of Brain Cancer

Human gut microbiota contains a large, complex, dynamic microbial community of approximately 10¹⁴ microbes from more than 1,000 microbial species, i.e., equivalent to 4 × 10⁶ genes. Numerous evidence links gut microbiota with human health and diseases. Importantly, gut microbiota is involved in the development and function of the brain through a bidirectional pathway termed as the gut-brain axis. Interaction between gut microbiota and immune responses can modulate the development of neuroinflammation and cancer diseases in the brain. With respect of brain cancer, gut microbiota could modify the levels of antioxidants, amyloid protein and lipopolysaccharides, arginase 1, arginine, cytochrome C, granulocyte-macrophage colony-stimulating factor signaling (GM-CSF), IL-4, IL-6, IL-13, IL-17A, interferon gamma (IFN-γ), reactive oxygen species (ROS), reactive nitrogen species (e.g., nitric oxide and peroxynitrite), short-chain fatty acids (SCFAs), tryptophan, and tumor necrosis factor-β (TGF-β). Through these modifications, gut microbiota can modulate apoptosis, the aryl hydrocarbon receptor (AhR), autophagy, caspases activation, DNA integrity, microglia dysbiosis, mitochondria permeability, T-cell proliferation and functions, the signal transducer and activator of transcription (STAT) pathways, and tumor cell proliferation and metastasis. The outcome of such interventions could be either oncolytic or oncogenic. This review scrutinizes the oncogenic and oncolytic effects of gut microbiota by classifying the modification mechanisms into (i) amino acid deprivation (arginine and tryptophan); (ii) kynurenine pathway; (iii) microglia dysbiosis; and (iv) myeloid-derived suppressor cells (MDSCs). By delineating the complexity of the gut-microbiota-brain-cancer axis, this review aims to help the research on the development of novel therapeutic strategies that may aid the efficient eradication of brain cancers.

Abnormal Levels of Some Biomarkers of Immune Activation Despite Very Early Treatment of Human Immunodeficiency Virus

BACKGROUND

Despite early antiretroviral therapy (ART), ART-suppressed people with human immunodeficiency virus (HIV) (PWH) remain at higher risk for infections and infection-related cancers than the general population. The immunologic pathways that remain abnormal in this setting, potentially contributing to these complications, are unclear.

METHODS

ART-suppressed PWH and HIV-negative controls, all cytomegalovirus seropositive and enriched for HIV risk factors, were sampled from an influenza vaccine responsiveness study. PWH were stratified by timing of ART initiation (within 6 months of infection [early ART] vs later) and nadir CD4+ T-cell count among later initiators. Between-group differences in kynurenine-tryptophan (KT) ratio, interferon-inducible protein 10, soluble CD14 and CD163, soluble tumor necrosis factor receptor 2, interleukin 6, and soluble urokinase plasminogen activator receptor were assessed after confounder adjustment.

RESULTS

Most participants (92%) were male, reflecting the demographics of early-ART initiators in San Francisco. Most biomarkers were higher among later-ART initiators. Participants in the early-ART group achieved near-normal soluble tumor necrosis factor receptor 2, interleukin 6, and soluble urokinase plasminogen activator receptor levels, but substantially higher KT ratio than those without HIV after confounder adjustment (P = .008). Soluble CD14, soluble CD163, and interferon-inducible protein 10 trended similarly.

CONCLUSIONS

While early-ART initiators restore near-normal levels of many inflammatory markers, the kynurenine pathway of tryptophan catabolism remains abnormally high. Because this pathway confers adaptive immune defects and predicts tuberculosis and cancer progression, this it may contribute to persistent risks of these complications in this setting.

Triple drugs co-delivered by a small gemcitabine-based carrier for pancreatic cancer immunochemotherapy

Poor tumor penetration and highly immunosuppressive tumor microenvironment are two major factors that limit the therapeutic efficacy for the treatment of pancreatic ductal adenocarcinoma (PDA). In this work, a redox-responsive gemcitabine (GEM)-conjugated polymer, PGEM, was employed as a tumor penetrating nanocarrier to co-load an immunomodulating agent (NLG919, an inhibitor of indoleamine 2,3-dioxygenase 1 (IDO1) and a chemotherapeutic drug (paclitaxel (PTX)) for immunochemo combination therapy. The NLG919/PTX co-loaded micelles showed very small size of ~15 nm. In vivo tumor imaging study indicated that PGEM was much more effective than the relatively large-sized POEG-co-PVD nanoparticles (~160 nm) in deep tumor penetration and could reach the core of the pancreatic tumor. PTX formulated in the PGEM carrier showed improved tumor inhibition effect compared with PGEM alone. Incorporation of NLG919 in the formulation led to a more immunoactive tumor microenvironment with significantly decreased percentage of Treg cells, and increased percentages of CD4+ IFNγ+ T and CD8+ IFNγ+ T cells. PGEM micelles co-loaded with PTX and NLG919 showed the best anti-tumor activity in pancreatic (PANC02) as well as two other tumor models compared to PGEM micelles loaded with PTX or NLG919 alone, suggesting that codelivery of NLG919 and PTX via PGEM may represent an effective strategy for immunochemotherapy of PDA as well as other types of cancers. STATEMENT OF SIGNIFICANCE: In order to effectively accumulate and penetrate the PDA that is poorly vascularized and enriched with dense fibrotic stroma, the size of nanomedicine has to be well controlled. Here, we reported an immunochemotherapy regimen based on co-delivery of GEM, PTX and IDO1 inhibitor NLG919 through an ultra-small sized GEM-based nanocarrier (PGEM). We demonstrated that the PGEM carrier was effective in accumulating and penetrating into PDA tumors. Besides, PGEM co-loaded with PTX and NLG9 induced an improved anti-tumor immune response and was highly efficacious in inhibiting tumor growth as well as in prolonging the survival rate in PANC02 xenograft model. Our work represents a potential strategy for enhancing PDA tumor penetration and immunochemotherapy.

Triple drugs co-delivered by a small gemcitabine-based carrier for pancreatic cancer immunochemotherapy

Poor tumor penetration and highly immunosuppressive tumor microenvironment are two major factors that limit the therapeutic efficacy for the treatment of pancreatic ductal adenocarcinoma (PDA). In this work, a redox-responsive gemcitabine (GEM)-conjugated polymer, PGEM, was employed as a tumor penetrating nanocarrier to co-load an immunomodulating agent (NLG919, an inhibitor of indoleamine 2,3-dioxygenase 1 (IDO1) and a chemotherapeutic drug (paclitaxel (PTX)) for immunochemo combination therapy. The NLG919/PTX co-loaded micelles showed very small size of ~15 nm. In vivo tumor imaging study indicated that PGEM was much more effective than the relatively large-sized POEG-co-PVD nanoparticles (~160 nm) in deep tumor penetration and could reach the core of the pancreatic tumor. PTX formulated in the PGEM carrier showed improved tumor inhibition effect compared with PGEM alone. Incorporation of NLG919 in the formulation led to a more immunoactive tumor microenvironment with significantly decreased percentage of Treg cells, and increased percentages of CD4⁺ IFNγ⁺ T and CD8⁺ IFNγ⁺ T cells. PGEM micelles co-loaded with PTX and NLG919 showed the best anti-tumor activity in pancreatic (PANC02) as well as two other tumor models compared to PGEM micelles loaded with PTX or NLG919 alone, suggesting that codelivery of NLG919 and PTX via PGEM may represent an effective strategy for immunochemotherapy of PDA as well as other types of cancers. STATEMENT OF SIGNIFICANCE: In order to effectively accumulate and penetrate the PDA that is poorly vascularized and enriched with dense fibrotic stroma, the size of nanomedicine has to be well controlled. Here, we reported an immunochemotherapy regimen based on co-delivery of GEM, PTX and IDO1 inhibitor NLG919 through an ultra-small sized GEM-based nanocarrier (PGEM). We demonstrated that the PGEM carrier was effective in accumulating and penetrating into PDA tumors. Besides, PGEM co-loaded with PTX and NLG9 induced an improved anti-tumor immune response and was highly efficacious in inhibiting tumor growth as well as in prolonging the survival rate in PANC02 xenograft model. Our work represents a potential strategy for enhancing PDA tumor penetration and immunochemotherapy.

Galectin 3 protects from cisplatin-induced acute kidney injury by promoting TLR-2-dependent activation of IDO1/Kynurenine pathway in renal DCs

Strategies targeting cross-talk between immunosuppressive renal dendritic cells (DCs) and T regulatory cells (Tregs) may be effective in treating cisplatin (CDDP)-induced acute kidney injury (AKI). Galectin 3 (Gal-3), expressed on renal DCs, is known as a crucial regulator of immune response in the kidneys. In this study, we investigated the role of Gal-3 for DCs-mediated expansion of Tregs in the attenuation of CDDP-induced AKI. Methods: AKI was induced in CDDP-treated wild type (WT) C57BL/6 and Gal-3 deficient (Gal-3^-/-) mice. Biochemical, histological analysis, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, real-time PCR, magnetic cell sorting, flow cytometry and intracellular staining of renal-infiltrated immune cells were used to determine the differences between CDDP-treated WT and Gal-3^-/- mice. Newly synthesized selective inhibitor of Gal-3 (Davanat) was used for pharmacological inhibition of Gal-3. Recombinant Gal-3 was used to demonstrate the effects of exogenously administered soluble Gal-3 on AKI progression. Pam3CSK4 was used for activation of Toll-like receptor (TLR)-2 in DCs. Cyclophosphamide or anti-CD25 antibody were used for the depletion of Tregs. 1-Methyl Tryptophan (1-MT) was used for pharmacological inhibition of Indoleamine 2,3-dioxygenase-1 (IDO1) in TLR-2-primed DCs which were afterwards used in passive transfer experiments. Results: CDDP-induced nephrotoxicity was significantly more aggravated in Gal-3^-/- mice. Significantly reduced number of immunosuppressive TLR-2 and IDO1-expressing renal DCs, lower serum levels of KYN, decreased presence of IL-10-producing Tregs and significantly higher number of inflammatory IFN-γ and IL-17-producing neutrophils, Th1 and Th17 cells were observed in the CDDP-injured kidneys of Gal-3^-/- mice. Pharmacological inhibitor of Gal-3 aggravated CDDP-induced AKI in WT animals while recombinant Gal-3 attenuated renal injury and inflammation in CDDP-treated Gal-3^-/- mice. CDDP-induced apoptosis, driven by Bax and caspase-3, was aggravated in Gal-3^-/- animals and in WT mice that received Gal-3 inhibitor (CDDP+Davanat-treated mice). Recombinant Gal-3 managed to completely attenuate CDDP-induced apoptosis in CDDP-injured kidneys of Gal-3^-/- mice. Genetic deletion as well as pharmacological inhibition of Gal-3 in renal DCs remarkably reduced TLR-2-dependent activation of IDO1/KYN pathway in these cells diminishing their capacity to prevent transdifferentiation of Tregs in inflammatory Th1 and Th17 cells. Additionally, Tregs generated by Gal-3 deficient DCs were not able to suppress production of IFN-γ and IL-17 in activated neutrophils. TLR-2-primed DCs significantly enhanced capacity of Tregs for attenuation of CDDP-induced AKI and inflammation and expression of Gal-3 on TLR-2-primed DCs was crucially important for their capacity to enhance nephroprotective and immunosuppressive properties of Tregs. Adoptive transfer of TLR-2-primed WTDCs significantly expanded Tregs in the kidneys of CDDP-treated WT and Gal-3^-/- recipients resulting in the suppression of IFN-γ and IL-17-driven inflammation and alleviation of AKI. Importantly, this phenomenon was not observed in CDDP-treated WT and Gal-3^-/- recipients of TLR-2-primed Gal-3^-/-DCs. Gal-3-dependent nephroprotective and immunosuppressive effects of renal DCs was due to the IDO1-induced expansion of renal Tregs since either inhibition of IDO1 activity in TLR-2-primed DCs or depletion of Tregs completely diminished DCs-mediated attenuation of CDDP-induced AKI. Conclusions: Gal-3 protects from CDDP-induced AKI by promoting TLR-2-dependent activation of IDO1/KYN pathway in renal DCs resulting in increased expansion of immunosuppressive Tregs in injured kidneys. Activation of Gal-3:TLR-2:IDO1 pathway in renal DCs should be further explored as new therapeutic approach for DC-based immunosuppression of inflammatory renal diseases.