Crosstalk between estrogen, dendritic cells, and SARS-CoV-2 infection.

The novel coronavirus disease 2019 (Covid-19) first appeared in Wuhan and has so far killed more than four million people worldwide. Men are more affected than women by Covid-19, but the cellular and molecular mechanisms behind these differences are largely unknown. One plausible explanation is that differences in sex hormones could partially account for this distinct prevalence in both sexes. Accordingly, several papers have reported a protective role of 17ß-estradiol during Covid-19, which might help explain why women appear less likely to die from Covid-19 than men. 17ß-estradiol is the predominant and most biologically active endogenous estrogen, which signals through estrogen receptor α, estrogen receptor ß, and G protein-coupled estrogen receptor 1. These receptors are expressed in mature cells from the innate and the adaptive immune system, particularly on dendritic cells (DCs), suggesting that estrogens could modulate their effector functions. DCs are the most specialized and proficient antigen-presenting cells, acting at the interface of innate and adaptive immunity with a powerful capacity to prime antigen-specific naive CD8+ T cells. DCs are richly abundant in the lung where they respond to viral infection. A relative increase of mature DCs in broncho-alveolar lavage fluids from Covid-19 patients has already been reported. Here we will describe how SARS-CoV-2 acts on DCs, the role of estrogen on DC immunobiology, summarise the impact of sex hormones on the immune response against Covid-19, and explore clinical trials regarding Covid-19.

Rituximab use for lymphoplasmacytic lymphoma during continuous renal replacement therapy. / Uso de rituximabe no tratamento de linfoma linfoplasmocítico durante terapia de substituição renal contínua.

Rituximab safety and efficacy in patients with renal impairment have not been established, nor have the effects of hemodialysis on serum rituximab level. There are only a few published case reports assessing serum rituximab level pre- and postdialysis. No data have been published regarding the usage of rituximab in patients with continuous renal replacement therapy. The authors present a case of a 59-year-old female patient who presented with paraneoplastic tetraparesis. She was admitted to the intensive care unit due to alveolar hemorrhage with respiratory failure and acute kidney injury requiring continuous renal replacement therapy. After a diagnostic workup, the diagnosis of lymphoplasmacytic lymphoma was established. Therapy with rituximab and cyclophosphamide was started. Rituximab levels were determined in serum and dialysate. No rituximab was found in the dialysate. The patient died after 2 months in the intensive care unit from nosocomial pneumonia due to multidrug-resistant Pseudomonas aeruginosa.

A segurança e a eficácia do rituximabe em pacientes com comprometimento renal não foram estabelecidas, e o mesmo ocorre com os efeitos da hemodiálise nos níveis séricos de rituximabe. Atualmente, apenas alguns relatos de caso avaliaram o nível sérico de rituximabe antes e após a diálise. Não foram até aqui publicados dados relativos ao uso de rituximabe em pacientes sob terapia de substituição renal contínua. Os autores apresentam um caso referente a uma mulher com 59 anos de idade atendida com quadro de tetraparesia paraneoplásica. Ela foi admitida no serviço de medicina intensiva devido a hemorragia alveolar com insuficiência respiratória e lesão renal aguda, que necessitou da utilização de terapia de substituição renal contínua. Após os procedimentos diagnósticos, estabeleceu-se o diagnóstico de linfoma linfoplasmocítico. Deu-se início ao tratamento com rituximabe e ciclofosfamida. Os níveis de rituximabe foram determinados no soro e no dialisato. Não se encontrou qualquer nível de rituximabe no dialisato. A paciente faleceu após 2 meses no serviço de medicina intensiva por pneumonia nosocomial causada por Pseudomonas aeruginosa resistente a múltiplos fármacos.

Uso de rituximabe no tratamento de linfoma linfoplasmocítico durante terapia de substituição renal contínua / Rituximab use for lymphoplasmacytic lymphoma during continuous renal replacement therapy

RESUMO A segurança e a eficácia do rituximabe em pacientes com comprometimento renal não foram estabelecidas, e o mesmo ocorre com os efeitos da hemodiálise nos níveis séricos de rituximabe. Atualmente, apenas alguns relatos de caso avaliaram o nível sérico de rituximabe antes e após a diálise. Não foram até aqui publicados dados relativos ao uso de rituximabe em pacientes sob terapia de substituição renal contínua. Os autores apresentam um caso referente a uma mulher com 59 anos de idade atendida com quadro de tetraparesia paraneoplásica. Ela foi admitida no serviço de medicina intensiva devido a hemorragia alveolar com insuficiência respiratória e lesão renal aguda, que necessitou da utilização de terapia de substituição renal contínua. Após os procedimentos diagnósticos, estabeleceu-se o diagnóstico de linfoma linfoplasmocítico. Deu-se início ao tratamento com rituximabe e ciclofosfamida. Os níveis de rituximabe foram determinados no soro e no dialisato. Não se encontrou qualquer nível de rituximabe no dialisato. A paciente faleceu após 2 meses no serviço de medicina intensiva por pneumonia nosocomial causada por Pseudomonas aeruginosa resistente a múltiplos fármacos.

ABSTRACT Rituximab safety and efficacy in patients with renal impairment have not been established, nor have the effects of hemodialysis on serum rituximab level. There are only a few published case reports assessing serum rituximab level pre- and postdialysis. No data have been published regarding the usage of rituximab in patients with continuous renal replacement therapy. The authors present a case of a 59-year-old female patient who presented with paraneoplastic tetraparesis. She was admitted to the intensive care unit due to alveolar hemorrhage with respiratory failure and acute kidney injury requiring continuous renal replacement therapy. After a diagnostic workup, the diagnosis of lymphoplasmacytic lymphoma was established. Therapy with rituximab and cyclophosphamide was started. Rituximab levels were determined in serum and dialysate. No rituximab was found in the dialysate. The patient died after 2 months in the intensive care unit from nosocomial pneumonia due to multidrug-resistant Pseudomonas aeruginosa.

Cellular and molecular mechanisms of glioblastoma malignancy: Implications in resistance and therapeutic strategies.

Glioblastoma (GB) is the more frequent and malignant brain tumour. In spite of all efforts, the median overall survival of GB patients remains approximately 15 months under therapy. The molecular biology underlying GB is complex, which highlight the need of specific treatment strategies. In fact, the deregulation of several molecular signalling pathways, the existence of the blood-brain barrier (BBB), that makes almost all the chemotherapeutic agents inaccessible to the tumour site, and the existence of a population of stem-like cells known to be responsible for tumour recurrence after therapy, can contribute to GB chemoresistance. In the present review, we summarize the reliable factors responsible for the failure of the most important chemotherapeutic agents in GB. Specifically, we describe the utmost important characteristics of the BBB, as well as the genetic, molecular and transcription factors alterations that lead to tumour malignancy, and ultimately their impact on stem-like cell plasticity modulation. Recently, nanocarriers have attracted increasing attention in brain- and tumour-targeted drug-delivery systems, owing to their potential ability to target cell surface specific molecules and to cross the BBB delivering the drug specifically to the tumour cells, improving efficacy and thus reducing non-specific toxicity. In this sense, we will lastly highlight the therapeutic challenges and improvements regarding GB treatment.

Choroidal thickness changes stratified by outcome in real-world treatment of diabetic macular edema.

PURPOSE: The aim of this study was to evaluate subfoveal choroidal thickness (SFCT) as a marker of outcome in real-world treatment of diabetic macular edema (DME) and to correlate it with choroidal thicknesses (CT) collected around the fovea. METHODS: Prospective interventional case series included a total of 126 eyes from 126 patients with recently diagnosed DME treated with a 3-monthly loading dose of ranibizumab or aflibercept and PRN thereafter until 24 months (M). CT was manually measured in the central 3500 µm area, subfoveally (SFCT), at 1750 µm right and left from the center in the horizontal plane and at 1750 µm up and down from the center in the vertical plane, by OCT. Anatomic (10% decrease in central retinal thickness) and functional (gain ≥ 5 letters) responses were assessed using univariate and multivariate analyses. The areas under ROC curves were used to assess whether baseline SFCT was a predictor of outcome. RESULTS: CT significantly decreased in all follow-ups (3 months after the 3 injections' loading dose (3M), 6 months (6M), 12 months (12M), 18 months (18M), 24 months (24M)). SFCT and other CT parameters are correlated. SFCT decrease from baseline was related with treatment (p = 0.003 to p < 0.001) but not with anatomic (3M, p = 0.858; 6M p = 0.762) or functional response (3M, p = 0.746; 6M, p = 0.156). SFCT was not found to be predictive of anatomic (AUC = 0.575, p = 0.172) or functional (AUC = 0.515, p = 0.779) outcome. CONCLUSIONS: SFCT is a reliable marker of choroidal thickness. Baseline SFCT decreased with anti-VEGF treatment but did not predict DME outcome.

Nucleolin is expressed in patient-derived samples and glioblastoma cells, enabling improved intracellular drug delivery and cytotoxicity.

One of the major challenges in Glioblastoma (GBM) therapy relates with the existence of glioma stem-like cells (GSCs), known to be chemo- and radio-resistant. GSCs and non-stem GBM cells have the ability to interchange, emphasizing the importance of identifying common molecular targets among those cell sub-populations. Nucleolin overexpression has been recently associated with breast cancer sub-populations with different stem-like phenotype. The goal of this work was to evaluate the potential of cell surface nucleolin as a target in GBM cells. Different levels of nucleolin expression resulted in a 3.4-fold higher association of liposomes targeting nucleolin (functionalized with the nucleolin-binding F3 peptide) in U87, relative to GBM11 glioblastoma cells. Moreover, nucleolin was suggested as a potential marker in OCT4-, NANOG-positive GSC, and in the corresponding non-stem GBM cells, as well as in SOX2-positive GSC. Doxorubicin delivered by liposomes targeting nucleolin enabled a level of cytotoxicity that was 2.5- or 4.6-fold higher compared to the non-targeted counterparts. Importantly, an overexpression of nucleolin was also observed in cells of patient-derived samples, as compared with normal brain. Overall, these results suggested nucleolin as a therapeutic target in GBM.

Glioblastoma entities express subtle differences in molecular composition and response to treatment.

Glioblastoma (GBM) is a grade IV astrocytoma. GBM patients show resistance to chemotherapy such as temozolomide (TMZ), the gold standard treatment. In order to simulate the molecular mechanisms behind the different chemotherapeutic responses in GBM patients we compared the cellular heterogeneity and chemotherapeutic resistance mechanisms in different GBM cell lines. We isolated and characterized a human GBM cell line obtained from a GBM patient, named GBM11. We studied the GBM11 behaviour when treated with Tamoxifen (TMX) that, among other functions, is a protein kinase C (PKC) inhibitor, alone and in combination with TMZ in comparison with the responses of U87 and U118 human GBM cell lines. We evaluated the cell death, cell cycle arrest and cell proliferation, mainly through PKC expression, by flow cytometry and western blot analysis and, ultimately, cell migration capability and f-actin filament disorganization by fluorescence microscopy. We demonstrated that the constitutive activation of p-PKC seems to be one of the main metabolic implicated on GBM malignancy. Despite of its higher resistance, possibly due to the overexpression of P-glycoprotein and stem-like cell markers, GBM11 cells presented a subtle different chemotherapeutic response compared to U87 and U118 cells. The GBM11, U87, U118 cell lines show subtle molecular differences, which clearly indicate the characterization of GBM heterogeneity, one of the main reasons for tumor resistance. The adding of cellular heterogeneity in molecular behaviour constitutes a step closer in the understanding of resistant molecular mechanisms in GBM, and can circumvents the eventual impaired therapy.

The Expression of Connexins and SOX2 Reflects the Plasticity of Glioma Stem-Like Cells.

Glioblastoma (GBM) is the most malignant primary brain tumor, with an average survival rate of 15 months. GBM is highly refractory to therapy, and such unresponsiveness is due, primarily, but not exclusively, to the glioma stem-like cells (GSCs). This subpopulation express stem-like cell markers and is responsible for the heterogeneity of GBM, generating multiple differentiated cell phenotypes. However, how GBMs maintain the balance between stem and non-stem populations is still poorly understood. We investigated the GBM ability to interconvert between stem and non-stem states through the evaluation of the expression of specific stem cell markers as well as cell communication proteins. We evaluated the molecular and phenotypic characteristics of GSCs derived from differentiated GBM cell lines by comparing their stem-like cell properties and expression of connexins. We showed that non-GSCs as well as GSCs can undergo successive cycles of gain and loss of stem properties, demonstrating a bidirectional cellular plasticity model that is accompanied by changes on connexins expression. Our findings indicate that the interconversion between non-GSCs and GSCs can be modulated by extracellular factors culminating on differential expression of stem-like cell markers and cell-cell communication proteins. Ultimately, we observed that stem markers are mostly expressed on GBMs rather than on low-grade astrocytomas, suggesting that the presence of GSCs is a feature of high-grade gliomas. Together, our data demonstrate the utmost importance of the understanding of stem cell plasticity properties in a way to a step closer to new strategic approaches to potentially eliminate GSCs and, hopefully, prevent tumor recurrence.

Urolithins impair cell proliferation, arrest the cell cycle and induce apoptosis in UMUC3 bladder cancer cells.

Ellagitannins have been gaining attention as potential anticancer molecules. However, the low bioavailability of ellagitannins and their extensive metabolization in the gastrointestinal tract into ellagic acid and urolithins suggest that the health benefits of consuming ellagitannins rely on the direct effects of their metabolites. Recently, chemopreventive and chemotherapeutic activities were ascribed to urolithins. Nonetheless, there is still a need to screen and evaluate the selectivity of these molecules and to elucidate their cellular mechanisms of action. Therefore, this work focused on the antiproliferative effects of urolithins A, B and C and ellagic acid on different human tumor cell lines. The evaluation of cell viability and the determination of the half-maximal inhibitory concentrations indicated that the sensitivity to the studied urolithins varied markedly between the different cell lines, with the bladder cancer cells (UMUC3) being the most susceptible. In UMUC3 cells, urolithin A was the most active molecule, promoting cell cycle arrest at the G2/M checkpoint, increasing apoptotic cell death and inhibiting PI3K/Akt and MAPK signaling. Overall, the present study emphasizes the chemopreventive/chemotherapeutic potential of urolithins, highlighting the stronger effects of urolithin A and its potential to target transitional bladder cancer cells.

Dual treatment with shikonin and temozolomide reduces glioblastoma tumor growth, migration and glial-to-mesenchymal transition.

PURPOSE: Glioblastomas (GBM) comprise 17% of all primary brain tumors. These tumors are extremely aggressive due to their infiltrative capacity and chemoresistance, with glial-to-mesenchymal transition (GMT) proteins playing a prominent role in tumor invasion. One compound that has recently been used to reduce the expression of these proteins is shikonin (SHK), a naphthoquinone with anti-tumor properties. Temozolomide (TMZ), the most commonly used chemotherapeutic agent in GBM treatment, has so far not been studied in combination with SHK. Here, we investigated the combined effects of these two drugs on the proliferation and motility of GBM-derived cells. METHODS: The cytotoxic and proliferative effects of SHK and TMZ on human GBM-derived cells were tested using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), Ki67 staining and BrdU incorporation assays. The migration capacities of these cells were evaluated using a scratch wound assay. The expression levels of ß3 integrin, metalloproteinases (MMPs) and GMT-associated proteins were determined by Western blotting and immunocytochemistry. RESULTS: We found that GBM-derived cells treated with a combination of SHK and TMZ showed decreases in their proliferation and migration capacities. These decreases were followed by the suppression of GMT through a reduction of ß3 integrin, MMP-2, MMP-9, Slug and vimentin expression via inactivation of PI3K/AKT signaling. CONCLUSION: From our results we conclude that dual treatment with SHK and TMZ may constitute a powerful new tool for GBM treatment by reducing therapy resistance and tumor recurrence.

Tamoxifen in combination with temozolomide induce a synergistic inhibition of PKC-pan in GBM cell lines.

BACKGROUND: Glioblastoma (GBM) is a highly proliferative, angiogenic grade IV astrocytoma that develops resistance to the alkylating agents used in chemotherapy, such as temozolomide (TMZ), which is considered the gold standard. The mean survival time for GBM patients is approximately 12 months, increasing to 14.6 months after TMZ treatment. The resistance of GBM to chemotherapy seems to be associated to genetic alterations and to the constitutive activation of several signaling pathways. Therefore, the combination of different drugs with different mechanisms of action may contribute to circumvent the chemoresistance of glioma cells. Here we describe the potential synergistic behavior of the therapeutic combination of tamoxifen (TMX), a known inhibitor of PKC, and TMZ in GBM. METHODS: We used two GBM cell lines incubated in absence and presence of TMX and/or TMZ and measured cell viability, proliferation, apoptosis, cell cycle, migration ability, cytoskeletal organization and the phosphorylated amount of the p-PKC-pan. RESULTS: The combination of low doses of TMX with increasing doses of TMZ shows an increased antiproliferative and apoptotic effect compared to the effect with TMX alone. CONCLUSIONS: The combination of TMX and TMZ seems to potentiate the effect of each other. These alterations seem to be associated to a decrease in the phosphorylation status of PKC. GENERAL SIGNIFICANCE: We emphasize that TMX is an inhibitor of the p-PKC-pan and that these combination is more effective in the reduction of proliferation and in the increase of apoptosis than each drug alone, which presents a new therapeutic strategy in GBM treatment.

PKC signaling in glioblastoma.

Glioblastoma Multiforme (GBM) is the most aggressive brain tumor characterized by intratumoral heterogeneity at cytopathological, genomic and transcriptional levels. Despite the efforts to develop new therapeutic strategies the median survival of GBM patients is 12-14 months. Results from large-scale gene expression profile studies confirmed that the genetic alterations in GBM affect pathways controlling cell cycle progression, cellular proliferation and survival and invasion ability, which may explain the difficulty to treat GBM patients. One of the signaling pathways that contribute to the aggressive behavior of glioma cells is the protein kinase C (PKC) pathway. PKC is a family of serine/threonine-specific protein kinases organized into three groups according the activating domains. Due to the variability of actions controlled by PKC isoforms, its contribution to the development of GBM is poorly understood. This review intends to highlight the contribution of PKC isoforms to proliferation, survival and invasive ability of glioma cells.

Therapeutic implications of an enriched cancer stem-like cell population in a human osteosarcoma cell line.

BACKGROUND: Osteosarcoma is a bone-forming tumor of mesenchymal origin that presents a clinical pattern that is consistent with the cancer stem cell model. Cells with stem-like properties (CSCs) have been identified in several tumors and hypothesized as the responsible for the relative resistance to therapy and tumor relapses. In this study, we aimed to identify and characterize CSCs populations in a human osteosarcoma cell line and to explore their role in the responsiveness to conventional therapies. METHODS: CSCs were isolated from the human MNNG/HOS cell line using the sphere formation assay and characterized in terms of self-renewal, mesenchymal stem cell properties, expression of pluripotency markers and ABC transporters, metabolic activity and tumorigenicity. Cell's sensitivity to conventional chemotherapeutic agents and to irradiation was analyzed and related with cell cycle-induced alterations and apoptosis. RESULTS: The isolated CSCs were found to possess self-renewal and multipotential differentiation capabilities, express markers of pluripotent embryonic stem cells Oct4 and Nanog and the ABC transporters P-glycoprotein and BCRP, exhibit low metabolic activity and induce tumors in athymic mice. Compared with parental MNNG/HOS cells, CSCs were relatively more resistant to both chemotherapy and irradiation. None of the treatments have induced significant cell-cycle alterations and apoptosis in CSCs. CONCLUSIONS: MNNG/HOS osteosarcoma cells contain a stem-like cell population relatively resistant to conventional chemotherapeutic agents and irradiation. This resistant phenotype appears to be related with some stem features, namely the high expression of the drug efflux transporters P-glycoprotein and BCRP and their quiescent nature, which may provide a biological basis for resistance to therapy and recurrence commonly observed in osteosarcoma.

Knocking out of CD38 accelerates development of a lupus-like disease in lpr mice.

OBJECTIVES: CD38 participates in lymphocyte ontogeny and function and may be involved in autoimmunity. Absence of CD38 accelerates development of non-obese diabetic (NOD) mice diabetes and anti-CD38 antibodies are good markers of human disease. Little is known regarding systemic autoimmunity. Active SLE patients have higher numbers of CD38(+) T and B cells. CD38 is a candidate gene for the murine Lmb2 lupus locus. We aimed to investigate whether CD38 was involved in lupus development. METHODS: We developed Cd38(-/-)-Fas(lpr)/Fas(lpr) mice and monitored them for development of a lupus-like disease through measurement of protein excretion in urine, histological assessment of the kidneys, quantification of circulating immunoglobulins and autoantibodies. We have also immunophenotyped 2- and 6-month old Cd38(-/-)-Fas(lpr)/Fas(lpr) mice. RESULTS: We found that absence of CD38 accelerated disease development: female Cd38(-/-)-Fas(lpr)/Fas(lpr) mice presented severe proteinuria, GN, deposition of ICs in the renal medulla and increased amounts of circulating immunoglobulin G (IgG), although anti-dsDNA autoantibodies and RF were not significantly increased at disease onset. We have found that Cd38(-/-)-Fas(lpr)/Fas(lpr) male mice, similarly to other murine models of lupus, were able to control disease. Absence of CD38 in lpr mice altered differentiation of T cells and dendritic cells (DC). CONCLUSION: Although the role of CD38 in tolerance is still to be elucidated, we provide evidence that it may play an active role in the control of a murine lupus-like disease.

Nitric oxide stimulates the proliferation of neural stem cells bypassing the epidermal growth factor receptor.

Nitric oxide (NO) was described to inhibit the proliferation of neural stem cells. Some evidence suggests that NO, under certain conditions, can also promote cell proliferation, although the mechanisms responsible for a potential proliferative effect of NO in neural stem cells have remained unaddressed. In this work, we investigated and characterized the proliferative effect of NO in cell cultures obtained from the mouse subventricular zone. We found that the NO donor NOC-18 (10 microM) increased cell proliferation, whereas higher concentrations (100 microM) inhibited cell proliferation. Increased cell proliferation was detected rapidly following exposure to NO and was prevented by blocking the mitogen-activated kinase (MAPK) pathway, independently of the epidermal growth factor (EGF) receptor. Downstream of the EGF receptor, NO activated p21Ras and the MAPK pathway, resulting in a decrease in the nuclear presence of the cyclin-dependent kinase inhibitor 1, p27(KIP1), allowing for cell cycle progression. Furthermore, in a mouse model that shows increased proliferation of neural stem cells in the hippocampus following seizure injury, we observed that the absence of inducible nitric oxide synthase (iNOS(-/-) mice) prevented the increase in cell proliferation observed following seizures in wild-type mice, showing that NO from iNOS origin is important for increased cell proliferation following a brain insult. Overall, we show that NO is able to stimulate the proliferation of neural stem cells bypassing the EGF receptor and promoting cell division. Moreover, under pathophysiological conditions in vivo, NO from iNOS origin also promotes proliferation in the hippocampus.

CXCL12/CXCR4 promotes motility and proliferation of glioma cells.

Glioblastoma (GBM) is the most aggressive and malignant brain tumor. Recent studies indicated that glioma samples are characterized by increased expression of CXCR4, the CXCL12/SDF-1 chemokine receptor. To better understand the role of CXCR4 in GBM biology we performed an integrated study where we simultaneously evaluate the contribution of the CXCR4/CXCL12 signaling pathway to the proliferation, survival and motility of a human GBM cell line. Our results indicated that CXCR4/CXCL12 axis induced an increase in cell proliferation and in cell motility. The blockage of CXCR4 induced a significant increase of apoptosis. Together, our results indicated that CXCR4/CXCL12 signalling pathway may contribute to GBM development and emphasize the therapeutic potential of this pathway in patients with GBM.

CD38 plays a role in effective containment of mycobacteria within granulomata and polarization of Th1 immune responses against Mycobacterium avium.

CD38 is a multifunctional ectoenzyme that behaves either as an enzyme, a cell adhesion molecule or as a cell surface receptor involved in cell signalling. It is expressed in cells of several lineages, including B and T lymphocytes, and macrophages. CD38 was shown to be important for the development of T-cell dependent humoral immune responses against extracellular pathogens. It also appears to be functionally important in macrophages, which are the host cells of Mycobacterium avium, an intracellular parasite that survives within these cells by avoiding a number of their microbicidal strategies. The present work aimed at investigating whether CD38 had any role on the immune response against mycobacterial infection. After intraperitoneal M. avium infection, the immune response of CD38KO mice was compared to that of their parental strain, C57Bl.6 mice. Absence of CD38 rendered mice more susceptible to mycobacterial infection. This susceptibility seems to be due to ineffective Th1 differentiation and polarization, which is essential for the control of M. avium infection. In addition, absence of CD38 seems to compromise the maintenance of the granulomatous barrier, leading to dissemination and unrestrained growth of mycobacteria.