Necrotic Cell Death and Inflammasome NLRP3 Activity in Mycobacterium bovis-Infected Bovine Macrophages

Mycobacterium bovis is a facultative intracellular bacterium that produces cellular necrosis in granulomatous lesions in bovines. Although M. bovis-induced inflammation actively participates in granuloma development, its role in necrotic cell death and in bovine macrophages has not been fully explored. In this study, we evaluate the effect of M. bovis AN5 and its culture filtrate protein extract (CFPE) on inflammasome activation in bovine macrophages and its consequences on cell death. Our results show that both stimuli induce necrotic cell death starting 4 h after incubation. CFPE treatment and M. bovis infection also induce the maturation of IL-1β (>3000 pg/mL), oligomerization of ASC (apoptosis-associated speck-like protein containing CARD), and activation of caspase-1, following the canonical activation pathway of the NLRP3 inflammasome. Inhibiting the oligomerization of NLRP3 and caspase-1 decreases necrosis among the infected or CFPE-stimulated macrophages. Furthermore, histological lymph node sections of bovines naturally infected with M. bovis contained cleaved gasdermin D, mainly in macrophages and giant cells within the granulomas. Finally, the induction of cell death (apoptosis and pyroptosis) decreased the intracellular bacteria count in the infected bovine macrophages, suggesting that cell death helps to control the intracellular growth of the mycobacteria. Our results indicate that M. bovis induces pyroptosis-like cell death that is partially related to the NLRP3 inflammasome activation and that the cell death process could control bacterial growth.

BCG∆BCG1419c and BCG differ in induction of autophagy, c-di-GMP content, proteome, and progression of lung pathology in Mycobacterium tuberculosis HN878-infected male BALB/c mice

The efficacy of BCG vaccines against Mycobacterium tuberculosis (Mtb) strains of lineage 2 (Beijing) in preclinical models and humans has been questioned. We have developed BCG∆BCG1419c, by deletion of BCG1419c in BCG Pasteur, which improved control of tuberculosis (TB) in preclinical models. Here, we compared the capacity of BCG and BCG∆BCG1419c to induce autophagy in murine macrophages, modify c-di-GMP content and transcript levels of BCG1416c, encoding the enzyme responsible for c-di-GMP synthesis/degradation, and of BCG1419c, encoding the phosphodiesterase involved in c-di-GMP degradation. Furthermore, we evaluated proteomic differences in vitro and compared protection against TB produced by a low dose of the HN878-Beijing strain at 3- and 6-months post-infection. We found that BCG∆BCG1419c induced more autophagy and produced different levels of c-di-GMP as well as different transcription of BCG1416c with no expression of BCG1419c. BCG∆BCG1419c differentially produced several proteins, including some involved in interaction with host cells. Vaccination with either BCG strain led to control of bacillary burden in lungs and spleen at 3- but not 6-months post-infection, whereas it reduced pneumonic areas compared with unvaccinated controls at 6 months post-infection. Vaccination with BCG∆BCG1419c delayed progression of lung necrosis as this was observed only at 6 months post-infection. Taken together, compared with BCG, BCG∆BCG1419c increased autophagy, presented different levels of c-di-GMP and transcription of BCG1416c in vitro in a growth-phase dependent manner, modified its proteome and delayed progression of lung pathology produced by a highly virulent Beijing strain.

Mycobacterium bovis naturally infected calves present a higher bacterial load and proinflammatory response than adult cattle

Granulomas are characteristic bovine tuberculosis lesions; studying this structure has improved our understanding of tuberculosis pathogenesis. However, the immune response that develops in granulomas of young cattle naturally infected with Mycobacterium bovis (M. bovis) has not been fully studied. Our previous work described an atypical pattern in granulomatous lesions of cattle younger than 4 months (calves) naturally infected previously M. bovis that did not correspond to the histological classification previously proposed. Histologically, granulomas from calves lack a connective tissue capsule and have fewer multinucleated giant cells (MGCs) and more acid-fast bacilli (AFB) than the classic tuberculosis lesions found in cattle older than 1 year (adults); this suggests a deficient immune response against M. bovis infection in young animals. Therefore, we used IHC and digital pathology analysis to characterize the in situ immune response of granulomas from young and adult cattle. The immunolabeling quantification showed that granulomas from calves had more mycobacteria, CD3⁺ cells, IFN-γ, TNF-α, and inducible nitric oxide synthase (iNOS) than those of adult cattle. Furthermore, calf granulomas showed lower immunolabeling of MAC387⁺, CD79⁺, and WC1⁺ cells without connective tissue surrounding the lesion and were associated with less vimentin, Alpha Smooth Muscle Actin (α-SMA), and TGF-β compared with granulomas from adult cattle. Our results suggest that the immune responses in granulomas of cattle naturally infected with M. bovis may be age dependent. This implies that an exacerbated proinflammatory response may be associated with active tuberculosis, producing more necrosis and a lower microbicidal capacity in the granulomas of calves naturally infected with M. bovis.

RRM1 and ERCC1 as biomarkers in patients with locally advanced and metastatic malignant pleural mesothelioma treated with continuous infusion of low-dose gemcitabine plus cisplatin

BACKGROUND

Malignant Pleural Mesothelioma (MPM) is a rare but aggressive neoplasia that usually presents at advanced stages. Even though some advances have been achieved in the management of patients with MPM, this malignancy continuous to impose a deleterious prognosis for affected patients (12-18 months as median survival, and 5-10% 5-year survival rate), accordingly, the recognition of biomarkers that allow us to select the most appropriate therapy are necessary.

METHODS

Immunohistochemistry semi-quantitative analysis was performed to evaluate four different biomarkers (ERCC1, RRM1, RRM2, and hENT-1) with the intent to explore if any of them was useful to predict response to treatment with continuous infusion gemcitabine plus cisplatin. Tissue biopsies from patients with locally advanced or metastatic MPM were analyzed to quantitatively asses the aforementioned biomarkers. Every included patient received treatment with low-dose gemcitabine (250 mg/m²) in a 6-h continuous infusion plus cisplatin 35 mg/m² on days 1 and 8 every 3 weeks as first-line therapy.

RESULTS

From the 70 eligible patients, the mean and standard deviation (SD) for ERCC1, RRM1, RRM2 and hENT-1 were 286,178.3 (± 219, 019.8); 104,647.1 (± 65, 773.4); 4536.5 (± 5, 521.3); and 2458.7 (± 4, 983.4), respectively. Patients with high expression of RRM1 had an increased median PFS compared with those with lower expression (9.5 vs 4.8 months, p = < 0.001). Furthermore, high expression of RRM1 and ERCC1 were associated with an increased median OS compared with their lower expression counterparts; [(23.1 vs 7.2 months for RRM1 p = < 0.001) and (17.4 vs 9.8 months for ERCC1 p = 0.018)].

CONCLUSIONS

ERCC1 and RRM1 are useful biomarkers that predict better survival outcomes in patients with advanced MPM treated with continuous infusion of gemcitabine plus cisplatin.

MicroRNA Profiling in Wilms Tumor: Identification of Potential Biomarkers

Wilms tumor (WT) is the most frequently diagnosed malignant renal tumor in children. With current treatments, ~90% of children diagnosed with WT survive and generally present with tumors characterized by favorable histology (FHWT), whereas prognosis is poor for the remaining 10% of cases where the tumors are characterized by cellular diffuse anaplasia (DAWT). Relatively few studies have investigated microRNA-related epigenetic regulation and its relationship with altered gene expression in WT. Here, we aim to identify microRNAs differentially expressed in WT and describe their expression in terms of cellular anaplasia, metastasis, and association with the main genetic alterations in WT to identify potential prognostic biomarkers. Expression profiling using TaqMan low-density array was performed in a discovery cohort consisting of four DAWT and eight FHWT samples. Relative quantification resulted in the identification of 109 (48.7%) microRNAs differentially expressed in both WT types. Of these, miR-10a-5p, miR-29a-3p, miR-181a-5p, miR-200b-3p, and miR-218-5p were selected and tested by RT-qPCR on a validation cohort of 53 patient samples. MiR-29a and miR-218 showed significant differences in FHWT with low (P = 0.0018) and high (P = 0.0131) expression, respectively. To discriminate between miRNA expression FHWTs and healthy controls, the receiver operating characteristic (ROC) curves were obtained; miR-29a AUC was 0.7843. Furthermore, low expression levels of miR-29a and miR-200b (P = 0.0027 and P = 0.0248) were observed in metastatic tumors. ROC curves for miR-29a discriminated metastatic patients (AUC = 0.8529) and miR-200b (AUC = 0.7757). To confirm the differences between cases with poor prognosis, we performed in situ hybridization for three microRNAs in five DAWT and 17 FHWT samples, and only significant differences between adjacent tissues and FHWT tumors were found for miR-181a, miR-200b, and miR-218, in both total pixels and nuclear analyses. Analysis of copy number variation in genes showed that the most prevalent alterations were WTX (47%), IGF2 (21%), 1q (36%) gain, 1p36 (16%), and WTX deletion/1q duplicate (26%). The five microRNAs evaluated are involved in the Hippo signaling pathway and participate in Wilms tumor development through their effects on differentiation, proliferation, angiogenesis, and metastasis.

Exercise Induces White Adipose Tissue Browning Across the Weight Spectrum in Humans

While the effect of exercise on white adipose tissue browning and metabolic improvement in rodents is clear, there are few studies in humans with inconclusive results. Thus, the aim of the study was to assess whether an exercise intervention promotes subcutaneous adipose tissue browning in humans, and whether this response is associated with metabolic improvement in three groups of individuals defined by body mass index (BMI) (kg/m²). Sedentary adult subjects with different BMI were enrolled in a 12-week bicycle-training program (3 times per week, intensity 70-80% HRmax). Brown and beige gene expression in subcutaneous adipose tissue (scWAT) biopsies, and serum glucose, insulin, lipid, adipokine, and myokine levels were compared before and after the exercise intervention. Thirty-three non-diabetic subjects (mean age 30.4 ± 4.6 years; 57.57% female; 13 normal weight, 10 overweight and 10 with obesity) completed the exercise intervention. Without any significant change in body composition, exercise improved several metabolic parameters, most notably insulin resistance and particularly in the overweight group. Circulating adiponectin, apelin, and irisin exercise-induced changes predicted 60% of the insulin sensitivity improvement. After exercise UCP1, TBX1, CPT1B scWAT expression significantly increased, along with P2RX5 significant positive staining. These changes are compatible with scWAT browning, however, they were not associated with glucose metabolism improvement. In conclusion, 12-weeks of exercise training produced brown/beige gene expression changes in abdominal scWAT of non-diabetic individuals with different BMI, which did not contribute to the metabolic improvement. However, this result should not be interpreted as a lack of effect of browning on metabolic parameters. These findings suggest that a bigger effect is needed and should not preclude the development of more effective strategies of browning. Furthermore, exercise-induced changes in adiponectin, apelin, and irisin predicted insulin sensitivity improvement, supporting the important role of adipokines and myokines in metabolism homeostasis.