Personalized management for phaeochromocytomas and paragangliomas in Latin America: A genetic perspective.

Phaeochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors with clinical heterogeneity and a high association with hereditary disease, affecting approximately 30 % of the cases. Differences in the presentation and genetic etiologies of PPGLs have been demonstrated between Chinese and European patients. The frequency of germline genetic diagnosis was remarkably higher in Brazilian patients (∼50 %) compared with other cohorts (Chinese 21 %, European 31 %, and The Cancer Genome Atlas Program cohort 27 %). Interestingly, germline SDHB genetic defects were also more prevalent in Brazilian patients (17 %) with PPGLs when compared with other cohorts (3-9 %). The SDHB exon 1 deletion was responsible for approximately 50 % of the SDHB pathogenic/likely pathogenic variants in Brazilian patients with PPGLs due to a founder effect. The germline SDHB exon 1 deletion represents ∼10 % of the germline drivers in Brazilian patients (and possibly in Latin America). Therefore, a single diagnostic PCR for the SDHB exon 1 deletion might be very useful in clinical practice for genetic testing and counseling of patients with PPGLs in Latin America.

Association between papillary thyroid cancer and primary aldosteronism in individuals with hypertension.

BACKGROUND: Aldosterone excess chronically induces oxidative stress and cell proliferation. Previously, a single study investigated primary aldosteronism (PA) in patients with papillary thyroid cancer (PTC), albeit without a matched control group. METHODS: We conducted a propensity score matched case-control study to investigate the association between PA and PTC in individuals with arterial hypertension (HT). PA was investigated in 137 patients with PTC and HT. The control group included 137 (1:1) age, sex-, and body mass index (BMI)-matched individuals with HT. We conducted a secondary analysis in which the controls were also matched according to HT stage. RESULTS: The prevalence of PA was 29.20% (95% confidence interval [CI], 21.91%-37.68%) in the PTC group and 20.44% (95% CI, 14.22%-28.35%) in the controls not matched for HT stage (p = 0.093). Although the PA prevalence was similar in both groups, the frequency of severe HT (stage III or resistant) was significantly lower in the PTC group (23%) compared to the hypertensive controls (73%, p < 0.001). After matching the controls by HT stage, the prevalence of PA in the PTC group was significantly higher compared to the hypertensive controls (9.56%; 95% CI, 5.39%-16.1%, p < 0.0001). In the multivariable analysis, PTC was independently associated with PA in both unmatched hypertensive individuals (odds ratio [OR] 4.74; 95% CI, 2.26-10.55; p< 0.001) and in those matched for HT stage (OR 5.88, 95% CI, 2.79-13.37; p< 0.001). CONCLUSION: PTC was an independent variable associated with a diagnosis of PA in hypertensive individuals. Therefore, we propose the association between PTC and HT as a new recommendation for PA screening regardless of HT severity.

Gasdermin-D activation promotes NLRP3 activation and host resistance to Leishmania infection.

Intracellular parasites from the Leishmania genus cause Leishmaniasis, a disease affecting millions of people worldwide. NLRP3 inflammasome is key for disease outcome, but the molecular mechanisms upstream of the inflammasome activation are still unclear. Here, we demonstrate that despite the absence of pyroptosis, Gasdermin-D (GSDMD) is active at the early stages of Leishmania infection in macrophages, allowing transient cell permeabilization, potassium efflux, and NLRP3 inflammasome activation. Further, GSDMD is processed into a non-canonical 25 kDa fragment. Gsdmd-/- macrophages and mice exhibit less NLRP3 inflammasome activation and are highly susceptible to infection by several Leishmania species, confirming the role of GSDMD for inflammasome-mediated host resistance. Active NLRP3 inflammasome and GSDMD are present in skin biopsies of patients, demonstrating activation of this pathway in human leishmaniasis. Altogether, our findings reveal that Leishmania subverts the normal functions of GSDMD, an important molecule to promote inflammasome activation and immunity in Leishmaniasis.

Evidence for a Founder Effect of SDHB Exon 1 Deletion in Brazilian Patients With Paraganglioma.

CONTEXT: Limited information is available concerning the genetic spectrum of pheochromocytoma and paraganglioma (PPGL) patients in South America. Germline SDHB large deletions are very rare worldwide, but most of the individuals harboring the SDHB exon 1 deletion originated from the Iberian Peninsula. OBJECTIVE: Our aim was to investigate the spectrum of SDHB genetic defects in a large cohort of Brazilian patients with PPGLs. METHODS: Genetic investigation of 155 index PPGL patients was performed by Sanger DNA sequencing, multiplex ligation-dependent probe amplification, and/or target next-generation sequencing panel. Common ancestrality was investigated by microsatellite genotyping with haplotype reconstruction, and analysis of deletion breakpoint. RESULTS: Among 155 index patients, heterozygous germline SDHB pathogenic or likely pathogenic variants were identified in 22 cases (14.2%). The heterozygous SDHB exon 1 complete deletion was the most frequent genetic defect in SDHB, identified in 8 out of 22 (36%) of patients. Haplotype analysis of 5 SDHB flanking microsatellite markers demonstrated a significant difference in haplotype frequencies in a case-control permutation test (P = 0.03). More precisely, 3 closer/informative microsatellites were shared by 6 out of 8 apparently unrelated cases (75%) (SDHB-GATA29A05-D1S2826-D1S2644 | SDHB-186-130-213), which was observed in only 1 chromosome (1/42) without SDHB exon 1 deletion (X2 = 29.43; P < 0.001). Moreover, all cases with SDHB exon 1 deletion had the same gene breakpoint pattern of a 15 678 bp deletion previously described in the Iberian Peninsula, indicating a common origin. CONCLUSION: The germline heterozygous SDHB exon 1 deletion was the most frequent genetic defect in the Brazilian PPGL cohort. Our findings demonstrated a founder effect for the SDHB exon 1 deletion in Brazilian patients with paragangliomas.

Modulation of the Host Nuclear Compartment by Trypanosoma cruzi Uncovers Effects on Host Transcription and Splicing Machinery.

Host manipulation is a common strategy for invading pathogens. Trypanosoma cruzi, the causative agent of Chagas Disease, lives intracellularly within host cells. During infection, parasite-associated modifications occur to the host cell metabolism and morphology. However, little is known about the effect of T. cruzi infection on the host cell nucleus and nuclear functionality. Here, we show that T. cruzi can modulate host transcription and splicing machinery in non-professional phagocytic cells during infection. We found that T. cruzi regulates host RNA polymerase II (RNAPII) in a time-dependent manner, resulting in a drastic decrease in RNAPII activity. Furthermore, host cell ribonucleoproteins associated with mRNA transcription (hnRNPA1 and AB2) are downregulated concurrently. We reasoned that T. cruzi may hijack the host U2AF35 auxiliary factor, a key regulator for RNA processing, as a strategy to affect the splicing machinery activities directly. In support of our hypothesis, we carried out in vivo splicing assays using an adenovirus E1A pre-mRNA splicing reporter, showing that intracellular T. cruzi directly modulates the host cells by appropriating U2AF35. For the first time, our results provide evidence of a complex and intimate molecular relationship between T. cruzi and the host cell nucleus during infection.

Upregulation of HOX genes promotes cell migration and proliferation in head and neck squamous cell carcinoma.

BACKGROUND: Expression dysregulation of HOX homeobox genes has been observed in several cancers, including head and neck squamous cell carcinoma (HNSC). Although characterization of HOX gene roles in HNSC development has been reported, there is still a need to better understand their real contribution to tumorigenesis. OBJECTIVE: The present study aimed to evaluate the contribution of the protein-coding HOX genes (HOXA10, HOXC9, HOXC10, and HOXC13) in cellular processes related to carcinogenesis and progression of the HNSC. METHODS: Expression of HOX genes was analyzed in HNSC RNA-Seq data from The Cancer Genome Atlas (TCGA) and by RT-qPCR in different tumor cell lines. siRNA-mediated knockdown of HOXA10, HOXC9, HOXC10 or HOXC13 was performed in HNSC cell lines, and predicted transcriptional targets HOX genes was analyzed by bioinformatic. RESULTS: Thirty-one out of the 39 mammalian HOX genes were found upregulated in HNSC tissues and cell lines. The HOXC9, HOXC10 or HOXC13 knockdown attenuated cell migration, and lead to downregulation of epithelial-mesenchymal transition (EMT) markers, which were predicted as transcriptional targets of these three HOX genes. Diminished colony formation and cell cycle arrest after HOXC10 or HOXC13 knockdown were also observed, corroborating the fact that there was an enrichment for genes in proliferation/cell cycle pathways. CONCLUSIONS: In summary, we revealed roles for HOXC9, HOXC10, and HOXC13 in cell migration and proliferation/cell cycle progression in HNSC cells and suggested that those HOX members contribute to HNSC development possibly by regulating tumor growth and metastasis.

Polymorphism in the catalytic subunit of the PI3Kγ gene is associated with Trypanosoma cruzi-induced chronic chagasic cardiomyopathy.

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi. During the chronic phase of disease, while most infected people do not present symptoms, characterizing the asymptomatic form, some patients develop the cardiac form or chronic chagasic cardiomyopathy, which is considered the most severe manifestation of this disease. Considering that the activation of the PI3Kγ signaling pathway is essential for an efficient immune response against T. cruzi infection, we evaluated the PIK3CG C > T (rs1129293) polymorphism in exon 3 of this gene, which encodes the catalytic subunit of PI3Kγ. The PIK3CG CT and TT genotypes were found to be associated with an increased risk of developing the cardiac form of the disease rather than the asymptomatic or digestive forms. In conclusion, the presence of the T allele at single or double doses may differentiate the cardiac from other clinical manifestations of Chagas disease. This finding should help in further studies to evaluate the mechanisms underlying the differential association of PIK3CG in Chagas disease.