Altered Vaginal Microbiota Composition Correlates With Human Papillomavirus and Mucosal Immune Responses in Women With Symptomatic Cervical Ectopy

Cervicovaginal microbiota disorder combined with the change of cytosine phosphate guanine motif- toll like receptor 9 axis was associated with cervical cancerization

BACKGROUND

Convincing studies demonstrated that cervicovaginal microbiota disorder and toll-like receptor 9 (TLR9) high expression were related to cervical carcinogenesis. However, the effects of cervicovaginal microbiota integration TLR9 in cervical cancerization are unclear. Based on the biological basis that unmethylated cytosine-phosphate-guanine (CpG) motifs of bacteria could activate TLR9, we explored the effects of cervicovaginal microbiota disorder and CpG motif-TLR9 axis change in cervical carcinogenesis.

METHODS

A total of 341 participants, including 124 normal cervical (NC), 90 low-grade cervical intraepithelial neoplasia (CIN1), 78 high-grade cervical intraepithelial neoplasia (CIN2/3) and 49 squamous cervical cancer (SCC), diagnosed by pathology were enrolled in the study. Here, metagenomic shotgun sequencing was used to reveal cervicovaginal microbiota characteristics, and TLR9 protein was detected by western blotting.

RESULTS

Our results showed that the diversity of cervicovaginal microbiota gradually increased along with the poor development of cervical lesions, showing the abundance of Lactobacillus crispatus and Lactobacillus iners decreased, while the abundance of pathogenic bacteria gradually increased. The level of TLR9 expression was gradually increased with cervicovaginal microbiota diversity increasing, the abundance of Lactobacillus decreasing, and we found a positive correlation dependency relationship (r = 0.384, P = 0.002) between TLR9 and GTCGTT motif content. Stratified analysis based on HPV16 infection, we found that the characteristics of cervicovaginal microbiota and increased TLR9 expression were also closely related to HPV16 infection.

CONCLUSIONS

Cervicovaginal microbiota dysbiosis might lead to the CpG motif increased, which was closely associated with TLR9 high expression, and ultimately might promote the progression of cervical lesions.

High risk HPV-positive women cervicovaginal microbial profiles in a Greek cohort: a retrospective analysis of the GRECOSELF study

Increasing evidence supports a role for the vaginal microbiome (VM) in the severity of HPV infection and its potential link to cervical intraepithelial neoplasia. However, a lot remains unclear regarding the precise role of certain bacteria in the context of HPV positivity and persistence of infection. Here, using next generation sequencing (NGS), we comprehensively profiled the VM in a series of 877 women who tested positive for at least one high risk HPV (hrHPV) type with the COBAS® 4,800 assay, after self-collection of a cervico-vaginal sample. Starting from gDNA, we PCR amplified the V3-V4 region of the bacterial 16S rRNA gene and applied a paired-end NGS protocol (Illumina). We report significant differences in the abundance of certain bacteria compared among different HPV-types, more particularly concerning species assigned to Lacticaseibacillus, Megasphaera and Sneathia genera. Especially for Lacticaseibacillus, we observed significant depletion in the case of HPV16, HPV18 versus hrHPVother. Overall, our results suggest that the presence or absence of specific cervicovaginal microbial genera may be linked to the observed severity in hrHPV infection, particularly in the case of HPV16, 18 types.

Vaginal microecology and its role in human papillomavirus infection and human papillomavirus associated cervical lesions

The vaginal microecology comprises the vaginal microbiome, immune microenvironment, vaginal anatomy, and the cervicovaginal fluid, which is rich in metabolites, enzymes, and cytokines. Investigating its role in the female reproductive system holds paramount significance. The advent of next-generation sequencing enabled a more profound investigation into the structure of the vaginal microbial community in relation to the female reproductive system. Human papillomavirus infection is prevalent among women of reproductive age, and persistent oncogenic HPV infection is widely recognized as a factor associated with cervical cancer. Extensive previous research has demonstrated that dysbiosis of vaginal microbiota characterized by a reduction in Lactobacillus species, heightens susceptivity to HPV infection, consequently contributing to persistent HPV infection and the progression of cervical lesion. Likewise, HPV infection can exacerbate dysbiosis. This review aims to provide a comprehensive summary of current literatures and to elucidate potential mechanisms underlying the interaction between vaginal microecology and HPV infection, with the intention of offering valuable insights for future clinical interventions.

The Role of Intratumor Microbiomes in Cervical Cancer Metastasis

BACKGROUND

Intratumor microbiomes can influence tumorigenesis and progression. The relationship between intratumor microbiomes and cervical cancer metastasis, however, remains unclear.

METHODS

We examined 294 cervical cancer samples together with information on microbial expression, identified metastasis-associated microbiomes, and used machine learning methods to validate their predictive ability on tumor metastasis. The tumors were subsequently typed based on differences in microbial expression. Differentially expressed genes in different tumor types were combined to construct a tumor-prognostic risk score model and a multiparameter nomogram model. In addition, we performed a functional enrichment analysis of differentially expressed genes to infer the mechanism of action between microbiomes and tumor cells.

RESULTS

Based on the 15 differentially expressed microbiomes, machine learning models were able to correctly predict the risk of cervical cancer metastasis. In addition, both the risk score and the nomogram model accurately predicted tumor prognosis. Differences in the expression of endogenous genes in tumors can influence the distribution of the intracellular microbiomes.

CONCLUSIONS

Intratumoral microbiomes in cervical cancer are associated with tumor metastasis and influence disease prognosis. A change in gene expression within tumor cells is responsible for differences in the microbial populations within the tumor.

Interactions between microbiota and cervical epithelial, immune, and mucus barrier

The female reproductive tract harbours hundreds of bacterial species and produces numerous metabolites. The uterine cervix is located between the upper and lower parts of the female genital tract. It allows sperm and birth passage and hinders the upward movement of microorganisms into a relatively sterile uterus. It is also the predicted site for sexually transmitted infection (STI), such as Chlamydia, human papilloma virus (HPV), and human immunodeficiency virus (HIV). The healthy cervicovaginal microbiota maintains cervical epithelial barrier integrity and modulates the mucosal immune system. Perturbations of the microbiota composition accompany changes in microbial metabolites that induce local inflammation, damage the cervical epithelial and immune barrier, and increase susceptibility to STI infection and relative disease progression. This review examined the intimate interactions between the cervicovaginal microbiota, relative metabolites, and the cervical epithelial-, immune-, and mucus barrier, and the potent effect of the host-microbiota interaction on specific STI infection. An improved understanding of cervicovaginal microbiota regulation on cervical microenvironment homeostasis might promote advances in diagnostic and therapeutic approaches for various STI diseases.

Torquetenovirus in pregnancy: Correlation with vaginal microbiome, metabolome and pro-inflammatory cytokines

Torquetenovirus (TTV) is a negative sense, single-stranded DNA virus present in many body fluids of apparently healthy individuals. At present, it is considered a non-pathogenic endogenous virus. TTV can be detected in the vagina of pregnant women, its abundance being modulated with the extent of immune system activation. Until now, there is only scarce information regarding the association between TTV and the composition of the vaginal environment. Therefore, this study aimed to assess the presence of TTV in the vaginal ecosystem of a cohort of white women with a normal pregnancy (n = 60) at different gestational stages (first, second and third trimester) and in 9 subjects suffering a first trimester miscarriage. For each woman, we determined (i) the presence and titer of TTV, (ii) the vaginal bacterial composition by means of Nugent score and 16S rRNA gene sequencing, (iii) the vaginal metabolic profiles through ¹H-NMR spectroscopy, and (iv) the vaginal concentration of two pro-inflammatory cytokines (IL-6 and IL-8). More than one third of women were found negative for TTV at all gestational stages. Although not statistically significant, the positivity for TTV dropped from 53.3% in the first to 36.6% in the third trimester. TTV loads varied greatly among vaginal samples, ranging between 2 × 10¹ and 2 × 10⁵ copies/reaction. No difference in TTV prevalence and loads was observed between women with normal pregnancies and miscarriages. The presence of TTV was more common in women with a higher vaginal leucocyte count (p = 0.02). The levels of IL-6 (p = 0.02), IL-8 (p = 0.03), propionate (p = 0.001) and cadaverine (p = 0.006) were significantly higher in TTV-positive samples. TTV titer was positively correlated with the concentrations of 4-hydroxyphenyllactate (p < 0.0001), isoleucine (p = 0.01) and phenylalanine (p = 0.04). TTV-positive samples were characterized by a higher relative abundance of Sneathia (p = 0.04) and Shuttleworthia (p = 0.0009). In addition, a trend toward a decrease of Lactobacillus crispatus and Lactobacillus jensenii, and an increase of Lactobacillus iners was observed for TTV-positive samples. In conclusion, we found that TTV is quite common in women with normal pregnancy outcomes, representing a possible predictor of local immune status.

Assessing the Cervicovaginal Microbiota in the Context of hrHPV Infections: Temporal Dynamics and Therapeutic Strategies

Cervical cancer is the third leading cause of female cancers globally, resulting in more than 300,000 deaths every year. The majority of all cervical cancers are caused by persistent infections with high-risk human papillomaviruses (hrHPV) that can progress to cancer via a series of premalignant lesions. Most women, however, clear this infection within a year, concomitant with disease regression. Both hrHPV clearance and disease regression have been associated with the composition of the cervicovaginal microenvironment, which is defined by the host immune system and the cervicovaginal microbiome (CVM). A healthy microbiome is generally characterized by a high abundance of Lactobacillus species, and a change in the composition may cause bacterial vaginosis (BV), which is associated with an increased susceptibility to persistent hrHPV infections and disease. In this review, the composition of the CVM is discussed, with emphasis on the possible causes that drive changes in the cervicovaginal microbiota in relation to hrHPV infections, disease progression, and disease regression. The literature search focused on the composition of the CVM and its correlation with hrHPV infections and neoplastic lesions as well as the current efforts to adjust the microbiome against adverse viral outcomes.