Cyclooxygenase-Derived Prostaglandin E2 Drives IL-1-Independent Mycobacterium bovis Bacille Calmette-Guérin-Triggered Skin Dendritic Cell Migration to Draining Lymph Node

BCG infection dose guides dendritic cell migration and T cell priming in the draining lymph node

In contrast to delayed-type hypersensitivity (DTH) and other hallmark reactions of cell-mediated immunity that correlate with vaccine-mediated protection against Mycobacterium tuberculosis, the contribution of vaccine dose on responses that emerge early after infection in the skin with Bacille Calmette-Guérin (BCG) is not well understood. We used a mouse model of BCG skin infection to study the effect of BCG dose on the relocation of skin Dendritic cells (DCs) to draining lymph node (DLN). Mycobacterium antigen 85B-specific CD4+ P25 T cell-receptor transgenic (P25 TCRTg) cells were used to probe priming to BCG in DLN. DC migration and T cell priming were studied across BCG inocula that varied up to 100-fold (104 to 106 Colony-forming units-CFUs). In line with earlier results in guinea pigs, DTH reaction in our model correlated with BCG dose. Importantly, priming of P25 TCRTg cells in DLN also escalated in a dose-dependent manner, peaking at day 6 after infection. Similar dose-escalation effects were seen for DC migration from infected skin and the accompanying transport of BCG to the DLN. BCG-triggered upregulation of co-stimulatory molecules on migratory DCs was restricted to the first 24 hour after infection and was independent of BCG dose over a 10-fold range (105 to 106 CFUs). The dose seemed to be a determinant of the number of total skin DCs that move to the DLN. In summary, our results support the use of higher BCG doses to detect robust DC migration and T cell priming.

NET-targeted therapy: effects, limitations, and potential strategies to enhance treatment efficacy

Neutrophil extracellular traps (NETs) are complex structures released by activated neutrophils during inflammatory responses. Due to their unique potential for causing tissue damage and modulating immune responses, there is increasing interest in studying these structures as potential targets for the treatment of infectious diseases, autoimmune diseases, and cancer. However, therapeutic targeting of NETs might trigger deleterious effects that may limit treatment efficacy. NET disruption may increase the microbial load in infection; in autoimmunity, NET targeting might impair peripheral tolerance, but it might reduce adaptive immune responses in cancer. In this review, we explore the therapeutic and deleterious effects of NET-targeted therapy while shedding light on novel strategies to overcome treatment-related limitations and enhance treatment efficacy.

Glucose metabolism and its role in the maturation and migration of human CD1c+ dendritic cells following exposure to BCG

Introduction

Tuberculosis (TB) still kills over 1 million people annually. The only approved vaccine, BCG, prevents disseminated disease in children but shows low efficacy at preventing pulmonary TB. Myeloid dendritic cells (mDCs) are promising targets for vaccines and immunotherapies to combat infectious diseases due to their essential role in linking innate and adaptive immune responses. DCs undergo metabolic reprogramming following exposure to TLR agonists, which is thought to be a prerequisite for a successful host response to infection. We hypothesized that metabolic rewiring also plays a vital role in the maturation and migration of DCs stimulated with BCG. Consequently, we investigated the role of glycolysis in the activation of primary human myeloid CD1c⁺ DCs in response to BCG.

Methods/results

We show that CD1c⁺ mDC mature and acquire a more energetic phenotype upon challenge with BCG. Pharmacological inhibition of glycolysis with 2-deoxy-D-glucose (2-DG) decreased cytokine secretion and altered cell surface expression of both CD40 and CCR7 on BCG-challenged, compared to untreated, mDCs. Furthermore, inhibition of glycolysis had differential effects on infected and uninfected bystander mDCs in BCG-challenged cultures. For example, CCR7 expression was increased by 2-DG treatment following challenge with BCG and this increase in expression was seen only in BCG-infected mDCs. Moreover, although 2-DG treatment inhibited CCR7-mediated migration of bystander CD1C⁺ DCs in a transwell assay, migration of BCG-infected cells proceeded independently of glycolysis.

Discussion

Our results provide the first evidence that glycolysis plays divergent roles in the maturation and migration of human CD1c⁺ mDC exposed to BCG, segregating with infection status. Further investigation of cellular metabolism in DC subsets will be required to determine whether glycolysis can be targeted to elicit better protective immunity against Mtb.

Secretome of human umbilical cord mesenchymal stem cell maintains skin homeostasis by regulating multiple skin physiological function

Skin is the largest organ in the body and the first defense to resist various diseases and external stimuli that easily cause infection and inflammation. Aseptic inflammation, barrier damage, and foreign aid pressure induce the destruction and damage to the skin microenvironment. Subsequently, it destroys the skin's physiological function, leading to the maintenance and circulation of steady-state imbalance and aggravating the process of skin disorders. Our study evaluated the therapeutic potential of the secretome of human umbilical cord mesenchymal stem cells (UC-CM) for dermatological diseases in adult human skin cells, ex vivo skin tissue, and a 3D skin model. Our data suggested several advantages of UC-CM due to (1) their low cytotoxicity and sensitization properties; (2) their anti-inflammatory capacity for treating inflammatory chronic cutaneous diseases; (3) their enhanced capacity of the skin barrier for treating abnormal barrier metabolism; and (4) their positive impact on restoring skin homeostasis due to effective regulation ability of skin physiological function including cell apoptosis, detoxification, and anti-aging. We thus envisage that the possibility of harnessing the therapeutic potential of UC-CM might benefit patients suffering from inflammatory skin disorders such as atopic dermatitis, acne, and psoriasis.