Unexpected Findings in Hereditary Breast and Ovarian Cancer Syndrome: Low-Level Constitutional Mosaicism in BRCA2.

Hereditary breast and ovarian cancer syndrome (HBOC) is a clinical entity characterized by an increased risk of developing breast and ovarian cancer. The genetic diagnosis is based on the identification of heterozygous germinal variants in HBOC susceptibility genes. However, it has recently been described that constitutional mosaic variants can contribute to the aetiology of HBOC. In constitutional mosaicism, individuals have at least two genotypically distinct populations of cells that arise from an early post-zygote event. The mutational event occurs early enough in development to affect several tissues. It is detected in germinal genetic studies as low variant allele frequency (VAF) variants (<30%) that are generally overlooked during the prioritization process. Constitutional mosaic variants can affect both somatic and germinal cells, and thus can be passed to the offspring and have important consequences for genetic counselling. In this work, we report the c.9648+1G>A mosaic variant in the BRCA2 gene and propose a diagnostic algorithm to deal with potential mosaic findings identified by Next Generation Sequencing (NGS).

A Large Case-Control Study Performed in Spanish Population Suggests That RECQL5 Is the Only RECQ Helicase Involved in Breast Cancer Susceptibility.

Around 50% of the familial breast cancer (BC) cases are estimated to be caused by germline variants in known low-, moderate-, and high-risk susceptibility genes, while the other half is of unknown genetic origin. In the present study, we wanted to evaluate the role of the RECQ helicases, some of which have been studied in the past as candidates, with unclear results about their role in the disease. Using next-generation sequencing (NGS) technology, we analyzed the whole coding sequence of BLM, RECQL1, RECQL4, RECQL5, and WRN in almost 2000 index cases from BC Spanish families that had previously tested negative for the known BC susceptibility genes (BRCAX) and compared the results with the controls extracted from gnomAD. Our results suggest that BLM, RECQL1, RECQL4, and WRN do not play a major role in BC susceptibility. However, in the combined analysis, joining the present results with those previously reported in a series of 1334 BC Spanish patients and controls, we found a statistically significant association between Loss of Function (LoF) variants in RECQL5 and BC risk, with an OR of 2.56 (p = 0.009; 95% CI, 1.18-4.98). Our findings support our previous work and places the RECQL5 gene as a new moderate-risk BC gene.

HCV eradication with DAAs differently affects HIV males and females: A whole miRNA sequencing characterization.

Gender-specific consequences after HCV eradication are unexplored. MicroRNAs (miRNAs) play a crucial role in the immune response against viral infections. However, few have highlighted miRNA role in sex-biased disease or therapy response. We aim to assess gender differences reflected in the miRNA expression of HIV/HCV-coinfected patients who achieve sustained virological response (SVR) with direct acting antivirals (DAAs). We conducted a prospective study of miRNA expression in PBMCs from 28 chronic HIV/HCV-coinfected patients (HIV/HCV) at baseline and after achieving SVR with DAAs. Sixteen HIV-monoinfected patients (HIV) and 36 healthy controls (HC) were used as controls. Identification of significant differentially expressed (SDE) miRNAs was performed with generalized linear model and mixed GLMs. We also explored putative dysregulated biological pathways. At baseline, the HIV/HCV patients showed differences in the miRNA profile concerning the HIV group (165 and 102 SDE miRNAs for males and females, respectively). Gender-stratified analysis of HIV/HCV group at baseline versus at SVR achievement showed higher differences in males (80 SDE miRNAs) than in females (55 SDE miRNAs). After SVR, HIV/HCV group showed similar values to HIV individuals, especially in females (1 SDE miRNA). However, ten miRNAs in males remained dysregulated, which were mainly involved in cancer, fatty acid, and inflammatory pathways. Taken together, our results show gender-biased dysregulation in the miRNA expression profile of PBMCs after HCV eradication with DAAs. These differences were normalized in females, while miRNA profile and their target-related pathways in males lack of normalization, which may be related to a high-risk of developing liver-related complications.

A Small Non-Coding RNA Modulates Expression of Pilus-1 Type in Streptococcus pneumoniae.

Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide, and about 30% of the pneumococcal clinical isolates show type I pili-like structures. These long proteinaceous polymers extending from the bacterial surface are encoded by pilus islet 1 and play major roles in adhesion and host colonization. Pili expression is bistable and is controlled by the transcriptional activator RlrA. In this work, we demonstrate that the previously identified small noncoding RNA srn135 also participates in pilus regulation. Our findings show that srn135 is generated upon processing of the 5'-UTR region of rrgA messenger and its deletion prevents the synthesis of RrgA, the main pili adhesin. Moreover, overexpression of srn135 increases the expression of all pili genes and rises the percentage of piliated bacteria within a clonal population. This regulation is mediated by the stabilization of rlrA mRNA since higher levels of srn135 increase its half-life to 165%. Our findings suggest that srn135 has a dual role in pilus expression acting both in cis- (on the RrgA levels) and in trans- (modulating the levels of RlrA) and contributes to the delicate balance between pili expressing and non-expressing bacteria.

RAD51D Aberrant Splicing in Breast Cancer: Identification of Splicing Regulatory Elements and Minigene-Based Evaluation of 53 DNA Variants.

RAD51D loss-of-function variants increase lifetime risk of breast and ovarian cancer. Splicing disruption is a frequent pathogenic mechanism associated with variants in susceptibility genes. Herein, we have assessed the splicing and clinical impact of splice-site and exonic splicing enhancer (ESE) variants identified through the study of ~113,000 women of the BRIDGES cohort. A RAD51D minigene with exons 2-9 was constructed in splicing vector pSAD. Eleven BRIDGES splice-site variants (selected by MaxEntScan) were introduced into the minigene by site-directed mutagenesis and tested in MCF-7 cells. The 11 variants disrupted splicing, collectively generating 25 different aberrant transcripts. All variants but one produced negligible levels (<3.4%) of the full-length (FL) transcript. In addition, ESE elements of the alternative exon 3 were mapped by testing four overlapping exonic microdeletions (≥30-bp), revealing an ESE-rich interval (c.202_235del) with critical sequences for exon 3 recognition that might have been affected by germline variants. Next, 26 BRIDGES variants and 16 artificial exon 3 single-nucleotide substitutions were also assayed. Thirty variants impaired splicing with variable amounts (0-65.1%) of the FL transcript, although only c.202G>A demonstrated a complete aberrant splicing pattern without the FL transcript. On the other hand, c.214T>C increased efficiency of exon 3 recognition, so only the FL transcript was detected (100%). In conclusion, 41 RAD51D spliceogenic variants (28 of which were from the BRIDGES cohort) were identified by minigene assays. We show that minigene-based mapping of ESEs is a powerful approach for identifying ESE hotspots and ESE-disrupting variants. Finally, we have classified nine variants as likely pathogenic according to ACMG/AMP-based guidelines, highlighting the complex relationship between splicing alterations and variant interpretation.

Different HCV Exposure Drives Specific miRNA Profile in PBMCs of HIV Patients.

Micro RNAs (miRNAs) are essential players in HIV and HCV infections, as both viruses modulate cellular miRNAs and interact with the miRNA-mediated host response. We aim to analyze the miRNA profile of HIV patients with different exposure to HCV to explore specific signatures in the miRNA profile of PBMCs for each type of infection. We massively sequenced small RNAs of PBMCs from 117 HIV+ infected patients: 45 HIV+ patients chronically infected with HCV (HIV/HCV+), 36 HIV+ that spontaneously clarified HCV after acute infection (HIV/HCV-) and 36 HIV+ patients without previous HCV infection (HIV). Thirty-two healthy patients were used as healthy controls (HC). Differential expression analysis showed significantly differentially expressed (SDE) miRNAs in HIV/HCV+ (n = 153), HIV/HCV- (n = 169) and HIV (n = 153) patients. We found putative dysregulated pathways, such as infectious-related and PI3K signaling pathways, common in all contrasts. Specifically, putatively targeted genes involved in antifolate resistance (HIV/HV+), cancer-related pathways (HIV/HCV-) and HIF-signaling (HIV) were identified, among others. Our findings revealed that HCV strongly influences the expression profile of PBMCs from HIV patients through the disruption of its miRNome. Thus, different HCV exposure can be identified by specific miRNA signatures in PBMCs.

Comparison of methods and characterization of small RNAs from plasma extracellular vesicles of HIV/HCV coinfected patients.

Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) hijack the host exosomal machinery as an additional mechanism of infection and evasion of the immune system, modifying the small RNA (smRNA) cargo during infection. We characterized the surface epitopes of extracellular vesicles (EVs) from plasma HIV/HCV-coinfected patients and their smRNA cargo profile, by comparing different isolation procedures. Six EVs isolation procedures were compared: ultracentrifugation, and five different polyethylene glycol-based methods (commercial, combined with a column purification step and two custom); and two RNA commercial kits (phenol and non-phenol based) were used. High-throughput sequencing of smRNAs was performed. Exosomal surface epitopes were analyzed by the MACSPlex Exosome Kit. Four miRNAs displayed differences among protocols (hsa-miR-205-5p and hsa-let-7a/b/f-5p). The selection of RNA isolation kit impacted on the detection of miRNAs and other smRNAs, where the phenol-based RNA isolation kit performed acceptably. EVs surface was enriched with HLA-DR/DP/DQ, CD81, and CD8. There were three liver-specific miRNAs overexpressed (let-7a-5p, miR-21-5p and hsa-miR-122-5p), thus, EVs cargo might reflect liver disease evolution. Other smRNAs such as piwi-interacting RNAs were also detected for the first time. Custom polyethylene glycol precipitation-based methods combined with an RNA phenol-based kit yielded the higher number of smRNAs for EVs isolated from plasma HIV/HCV patients.

TNFAIP3, TNIP1, and MyD88 Polymorphisms Predict Septic-Shock-Related Death in Patients Who Underwent Major Surgery.

BACKGROUND: In many immune-related diseases, inflammatory responses and several clinical outcomes are related to increased NF-κB activity. We aimed to evaluate whether SNPs related to the NF-κB signaling pathway are associated with higher susceptibility to infection, septic shock, and septic-shock-related death in European patients who underwent major surgery. METHODS: We performed a case-control study on 184 patients with septic shock and 212 with systemic inflammatory response syndrome, and a longitudinal substudy on septic shock patients. Thirty-three SNPs within genes belonging to or regulating the NF-κB signaling pathway were genotyped by Agena Bioscience's MassARRAY platform. RESULTS: No significant results were found for susceptibility to infection and septic shock in the multivariate analysis after adjusting for multiple comparisons. Regarding septic-shock-related death, patients with TNFAIP3 rs6920220 AA, TNIP1 rs73272842 AA, TNIP1 rs3792783 GG, and TNIP1 rs7708392 CC genotypes had the highest risk of septic-shock-related death in the first 28 and 90 days. Also, the MyD88 rs7744 GG genotype was associated with a higher risk of death during the first 90 days. Haplotype analysis shows us that patients with the TNIP1 GAG haplotype (composed of rs73272842, rs3792783, and rs7708392) had a lower risk of death in the first 28 days and the TNIP1 AGC haplotype was associated with a higher risk of death in the first 90 days. CONCLUSIONS: The SNPs in the genes TNFAIP3, TNIP1, and MyD88 were linked to the risk of septic-shock-related death in patients who underwent major surgery.

MicroRNA Profile of HCV Spontaneous Clarified Individuals, Denotes Previous HCV Infection.

Factors involved in the spontaneous cleareance of a hepatitis C (HCV) infection are related to both HCV and the interaction with the host immune system, but little is known about the consequences after a spontaneous resolution. The main HCV extrahepatic reservoir is the peripheral blood mononuclear cells (PBMCs), and their transcriptional profile provides us information of innate and adaptive immune responses against an HCV infection. MicroRNAs regulate the innate and adaptive immune responses, and they are actively involved in the HCV cycle. High Throughput sequencing was used to analyze the miRNA profiles from PBMCs of HCV chronic naïve patients (CHC), individuals that spontaneously clarified HCV (SC), and healthy controls (HC). We did not find any differentially expressed miRNAs between SC and CHC. However, both groups showed similar expression differences (21 miRNAs) with respect to HC. This miRNA signature correctly classifies HCV-exposed (CHC and SC) vs. HC, with the has-miR-21-3p showing the best performance. The potentially targeted molecular pathways by these 21 miRNAs mainly belong to fatty acids pathways, although hippo signaling, extracellular matrix (ECM) interaction, proteoglycans-related, and steroid biosynthesis pathways were also altered. These miRNAs target host genes involved in an HCV infection. Thus, an HCV infection promotes molecular alterations in PBMCs that can be detected after an HCV spontaneous resolution, and the 21-miRNA signature is able to identify HCV-exposed patients (either CHC or SC).

The Myeloid-Epithelial-Reproductive Tyrosine Kinase (MERTK) rs4374383 Polymorphism Predicts Progression of Liver Fibrosis in Hepatitis C Virus-Infected Patients: A Longitudinal Study.

BACKGROUND: The myeloid-epithelial-reproductive tyrosine kinase (MERTK) is involved in hepatic steatosis, inflammation, and liver fibrosis. Here we evaluated the association between the MERTK rs4374383 single nucleotide polymorphism (SNP) and liver fibrosis progression in hepatitis C virus (HCV)-infected patients. METHODS: We performed a retrospective study (repeated measures design) in 208 patients who had liver stiffness measurement (LSM), which was assessed using transient elastography. No patient had cirrhosis at baseline (LSM ≥ 12.5 kPa). RESULTS: At baseline, 53.8% were male, the median age was 47.1 years, 13.5% reported a high intake of alcohol, 10.1% were prior injection drug users, 85.3% were infected with HCV genotype 1, and 22.6% had previously failed antiviral therapy (pegylated-interferon-alpha/ribavirin). During a median follow-up of 46.6 months, 26 patients developed cirrhosis. The rs4374383 G carriers had a higher risk of increasing LSM (adjusted arithmetic mean ratio (aAMR) = 1.14; p = 0.006) and a higher likelihood of having an increase in LSM greater than 5 kPa (ΔLSM ≥ 5 kPa) (adjusted odds ratio (aOR) = 2.37; p = 0.029), and greater than 7 kPa (ΔLSM ≥ 7 kPa) (aOR = 3.24; p = 0.032), after controlling for confounding. The SNP's association with cirrhosis progression was close to statistical significance (aOR = 2.18; p = 0.070). CONCLUSIONS: MERTK rs4374383 A carriers had a lower risk of liver fibrosis progression than G carriers, supporting the hypothesis that this SNP seems to have a critical role in the pathogenesis of liver disease in HCV-infected patients.

PNPLA3 rs738409 polymorphism is associated with liver fibrosis progression in patients with chronic hepatitis C: A repeated measures study.

BACKGROUND: Host genetic background has been associated with liver fibrosis progression. OBJECTIVE: To analyze the association between the patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 polymorphism and liver fibrosis progression in hepatitis C virus (HCV)-infected patients. STUDY DESIGN: In this retrospective cohort study, 187 patients with chronic HCV infection were included, who had at least two liver stiffness measurements (LSM) by transient elastography during the follow-up. Results were expressed in kilopascals (kPa). The analysis of genetic association was carried out according to additive model by using Generalized Linear Models. RESULTS: No patients had advanced fibrosis/cirrhosis at baseline. During a median follow-up time of 47.9 months, 15 patients developed advanced fibrosis and 17 cirrhosis. In multivariate analysis adjusted by the main clinical and epidemiological covariates, the rs738409 G allele was related to higher increase of LSM values during the follow-up (adjusted arithmetic mean ratio (aAMR) = 1.16 (95%CI = 1.04; 1.29); p = .006) and higher odds of having progression to advanced fibrosis [aOR = 2.03 (95%CI = 1.01; 4.06); p = .045], and progression to cirrhosis [aOR = 3.03 (95%CI = 1.26; 7.30); p = .014]. CONCLUSIONS: PNPLA3 rs738409 polymorphism appears to be related to the increased progression of liver fibrosis in HCV infected patients.

Absence of tmRNA Has a Protective Effect against Fluoroquinolones in Streptococcus pneumoniae.

The transfer messenger RNA (tmRNA), encoded by the ssrA gene, is a small non-coding RNA involved in trans-translation that contributes to the recycling of ribosomes stalled on aberrant mRNAs. In most bacteria, its inactivation has been related to a decreased ability to respond to and recover from a variety of stress conditions. In this report, we investigated the role of tmRNA in stress adaptation in the human pathogen Streptococcus pneumoniae. We constructed a tmRNA deletion mutant and analyzed its response to several lethal stresses. The ΔssrA strain grew slower than the wild type, indicating that, although not essential, tmRNA is important for normal pneumococcal growth. Moreover, deletion of tmRNA increased susceptibility to UV irradiation, to exogenous hydrogen peroxide and to antibiotics that inhibit protein synthesis and transcription. However, the ΔssrA strain was more resistant to fluoroquinolones, showing twofold higher MIC values and up to 1000-fold higher survival rates than the wild type. Deletion of SmpB, the other partner in trans-translation, also reduced survival to levofloxacin in a similar extent. Accumulation of intracellular reactive oxygen species associated to moxifloxacin and levofloxacin treatment was also highly reduced (∼100-fold). Nevertheless, the ΔssrA strain showed higher intracellular accumulation of ethidium bromide and levofloxacin than the wild type, suggesting that tmRNA deficiency protects pneumococcal cells from fluoroquinolone-mediated killing. In fact, analysis of chromosome integrity revealed that deletion of tmRNA prevented the fragmentation of the chromosome associated to levofloxacin treatment. Moreover, such protective effect appears to relay mainly on inhibition of protein synthesis, since a similar effect was observed with antibiotics that inhibit that process. The emergence and spread of drug-resistant pneumococci is a matter of concern and these results contribute to a better comprehension of the mechanisms underlying fluoroquinolones action.