Potential immunomodulatory effect of allelochemical juglone in mice vaccinated with BCG

Prolyl isomerase Pin1 sculpts the immune microenvironment of colorectal cancer

Pin1, a peptide prolyl cis-trans isomerase, is overexpressed and/or overactivated in many human malignancies. However, whether Pin1 regulates the immunosuppressive TME has not been well defined. In this study, we detected the effect of Pin1 on immune cells and immune checkpoint PD-L1 in the TME of CRC and explored the anti-tumor efficacy of Pin1 inhibitor ATRA combined with PD-1 antibody. We found that Pin1 facilitated the immunosuppressive TME by raising the proportion of myeloid-derived suppressor cells (MDSCs) and declining the percentage of CD8+ T cells and CD4+ T cells. Pin1 restrained PD-L1 protein expression in CRC cells and the effect was tempered by endoplasmic reticulum (ER) stress inducers. Mechanically, Pin1 overexpression decreased the stability of PD-L1 and promoted its degradation by mitigating ER stress. Silencing or inhibiting Pin1 promoted PD-L1 protein expression by inducing ER stress. Hence, Pin1 inhibitor ATRA enhanced the anti-tumor efficacy of PD-1 antibody in the CRC allograft by upregulating PD-L1. Our results reveal the critical and pleiotropic effects of Pin1 on managing the immune cells and immune checkpoint PD-L1 in the TME of CRC, providing a new promising candidate for combination with immunotherapy.

Silk Fibroin-Coated Nano-MOFs Enhance the Thermal Stability and Immunogenicity of HBsAg

Vaccines are widely regarded as one of the most effective weapons in the fight against infectious diseases. Currently, vaccines must be stored and transported at low temperatures as high temperatures can lead to a loss of vaccine conformation and reduced therapeutic efficacy. Metal-organic frameworks (MOFs), such as zeolitic imidazole framework-8 (ZIF-8), are a new class of hybrid materials with large specific surface areas, high loading rates, and good biocompatibility and are successful systems for vaccine delivery and protection. Silk fibroin (SF) has a good biocompatibility and thermal stability. In this study, the hepatitis B surface antigen (HBsAg) was successfully encapsulated in ZIF-8 to form HBsAg@ZIF-8 (HZ) using a one-step shake and one-pot shake method. Subsequently, the SF coating modifies HZ through hydrophobic interactions to form HBsAg/SF@ZIF-8 (HSZ), which enhanced the thermal stability and immunogenicity of HBsAg. Compared to free HBsAg, HZ and HSZ improved the thermostability of HBsAg, promoted the antigen uptake and lysosomal escape, stimulated dendritic cell maturation and cytokine secretion, formed an antigen reservoir to promote antibody production, and activated CD4+ T and CD8+ T cells to enhance memory T-cell production. Importantly, HSZ induced a strong immune response even after 14 days of storage at 25 °C. Furthermore, the nanoparticles prepared by the one-step shake method exhibited superior properties compared to those prepared by the one-pot shake method. This study highlights the importance of SF-coated ZIF-8, which holds promise for investigating thermostable vaccines and breaking the vaccine cold chain.

Acute and sub-acute oral toxicity assessment of 5-hydroxy-1,4-naphthoquinone in mice

5-hydroxy-1,4-naphthoquinone (5NQ) or juglone is a bioactive molecule found in walnuts and has shown therapeutic effects in various disease models. Limited information is available regarding the toxicity of 5NQ, thereby limiting the clinical development of this drug. In the present study, oral acute (50, 300 and 2000 mg/kg) and sub-acute toxicity (5, 15 and 50 mg/kg) was assessed in mice to evaluate the safety of 5NQ. The acute toxicity study identified 118 mg/kg as the point-of-departure dose (POD) for single oral administration of 5NQ using benchmark dose modeling (BMD). Repeated administration of 5NQ at doses of 15 and 50 mg/kg/day caused reduction in food consumption and body weight of mice along with alterations in liver and renal function. Histopathological assessment revealed significant damage to hepatic and renal tissues at all doses in the acute toxicity study, and at higher doses of 15 and 50 mg/kg in the sub-acute toxicity study. We observed dose dependent mortality in sub-acute toxicity study and the no observed adverse effect level (NOAEL) was established as < 5 mg/kg/day. Modeling the survival response in sub-acute toxicity study identified 1.74 mg/kg/day as the POD for repeated administration of 5NQ. Serum levels of aspartate aminotransferase (AST) were most sensitive to 5NQ administration with a lower limit of BMD interval (BMDL) of 1.1 × 10-3 mg/kg/day. The benchmark doses reported in the study can be further used to determine a reference dose of 5NQ for human risk assessment.

Plant Phenolics as Pathogen-Carrier Immunogenicity Modulator Haptens

Background

Pathogens use multiple mechanisms to disrupt cell functioning in their host and allow pathogenesis. These mechanisms involve communication between the pathogen and the host cell through protein-protein interactions.

Methods

Protein-protein interactions chains referred to as signal transduction pathways are the processes by which a chemical or physical signal transmits through a cell as series of molecular events so the pathogen needs to intercept these molecular pathways at few positions to induce pathogenesis such as pathogen viability, infection or hypersensitivity.

Results

The pathogen nodes of interception are not necessarily the most immunogenic; so that novel immunogenicity-improvement strategies need to be developed thought a chemical conjugation of the pathogen-carrier nodes to develop an efficient immune response in order to block pathogenesis. On the other hand, if pathogen-carriers are immunogens; toleration ought to be induced by this conjugation avoiding hypersensitivity. Thus, this paper addresses the biological plausibility of plant-phenolics as pathogen-carrier immunogenicity modulator haptens.

Conclusion

The plant-phenolic compounds have in their structure functional groups such as hydroxyl, carbonyl, carboxyl, ester, or ether, capable of reacting with the amino or carbonyl groups of the amino acids of a pathogen-carrier to form conjugates. Besides, the varied carbon structures these phenolic compounds have; it is possible to alter the pathogen-carrier related factors that determine the immunogenicity: 1) Structural complexity, 2) Molecular size, 3) Structural heterogeneity, 4) Accessibility to antigenic determinants or epitopes, 5) Optical configuration, 6) Physical state, or 7) Molecular rigidity.

Distinct epigenetic regulation in patients with multidrug-resistant TB-HIV co-infection and uninfected individuals

BACKGROUND

Mycobacterium tuberculosis (Mtb) is an airborne pathogenic microorganism that causes tuberculosis (TB). This pathogen invades lung tissues causing pulmonary infections and disseminates into other host organs. The Bacillus Calmette-Guérin (BCG) vaccine is employed to provide immune protection against TB; however, its efficacy is dependent on the age, immune status and geographic location of vaccinated individuals. Advanced diagnostic approaches such as GeneXpert MTB/RIF® and line probe assays (LPAs) have allowed rapid detection of drug-resistant, multidrug-resistant (MDR) and extensively drug-resistant (XDR) Mtb strains. However, in sub-Saharan Africa, public and private health institutions are further burdened by the high prevalence of Human Immunodeficiency Virus (HIV), the causative agent of acquired immunodeficiency syndrome (AIDS) and TB co-infections across different age groups. Epigenetic mechanisms have been widely exploited by Mtb and HIV to bypass the host's innate and adaptive immune responses, leading to microbial proliferation and disease manifestation. In the current study, we investigated the impact of epigenetic mechanisms in regulating target gene expression in healthy and patients co-infected with MDR TB-HIV.

Juglone eliminates MDSCs accumulation and enhances antitumor immunity

Myeloid-derived suppressor cells (MDSCs) contribute to immune activity suppression and promote the tumor progression. Elimination of MDSCs is a promising cancer therapeutic strategy, and some chemotherapeutic agents have been reported to hamper tumor progression by suppressing MDSCs. Juglone has been showed to exert a direct cytotoxic effect on tumor cells. However, the effect of juglone on MDSCs and anti-tumor immune statue has remained unexplored. In our study, we observed that juglone suppressed tumor growth and metastasis markedly, and the tumor growth suppression in immunocompetent mice was more drastic than that in immunodeficient mice. Juglone reduced the accumulation of MDSCs and increased IFN-γ production by CD8⁺ T cells. Consistently, juglone affected myeloid cells differentiation and maturation, impairing the immunosuppressive functions of MDSCs. Moreover, juglone down-regulated the level of IL-1β which was mediating accumulation of MDSCs. In addition, juglone inhibited 5FU-induced liver injury in a colorectal carcinoma-bearing mice model. Thus, our work suggests that the anti-tumor effect of juglone is mediated, at least in part, by eliminating accumulation of MDSCs.