Khondoker M. Akram

Background: While the human placental bacteriome has been extensively studied, information regarding the virome remains limited. Initial trigger(s) and subsequent pathogenesis of spontaneous preterm birth (PTB) remain elusive. The association between subclinical placental viral infections and spontaneous preterm birth (PTB) is poorly understood.Methods: In this study, we examined fresh placental samples from women in the UK, Bangladesh, and South Africa to elucidate the virome profiles and association with spontaneous PTB. We employed shotgun metagenomics, real-time PCR, and Gram staining, complemented by bioinformatics, to detect both viruses and bacteria in the decidua and chorionic villous tissues.Findings: We identified distinct placental viromes across the three populations, with different viral species detected in 27.8% of UK, 10.1% of Bangladeshi, and 95.8% of South African women. However, no virus was associated with preterm birth. We did not identify any known pathogenic viruses in 236 placental samples, except for one preterm placenta from the Bangladeshi cohort, where human herpesvirus 6 was detected. Most of the viruses were bacteriophages present at very low abundance and low frequencies across the three cohorts. Lambdavirus lambda was detected in 14% of UK and 11% of Bangladeshi samples but was absent in South African samples. Papiine betaherpesvirus 3 was identified in 62.5% of South African placentas. Punavirus (29.1%) and Streptococcus phages (16.67%) were also prevalent in South African samples. A variety of bacterial species, including Moraxella osloensis, Delftia lacustris, Cutibacterium acnes,Escherichia coli and Staphylococcus epidermidis, were detected in samples across the three cohorts in variable frequencies but without any notable tissue immune responses. None of the viruses or bacteria was associated with PTB, except D. lacustris, which was significantly more abundant in preterm than in term placentas in the Bangladeshi cohort.Interpretation: We conclude that the human placenta harbours a virome predominated by bacteriophages and that subclinical viral infection in spontaneous PTB is rare. However, the potential opportunistic roles of these viral species warrant further investigation to clarify virome-bacteriome interactions in adverse pregnancy outcomes.

While the human placental microbiome has been extensively studied, information regarding the virome remains limited. The association between subclinical placental viral infections and spontaneous preterm birth (PTB) is poorly understood. Hence, we examined fresh placenta samples from women in the UK, Bangladesh, and South Africa to elucidate the virome profiles and association with spontaneous PTB. We employed shotgun metagenomics, real-time PCR, and Gram staining, complemented by bioinformatics, to detect both viruses and bacteria in the decidua and chorionic villous tissues. We did not identify any known pathogenic viruses in 236 placental samples, except for one preterm placenta from the Bangladeshi cohort, where human herpesvirus 6 was detected. The majority of the viruses were bacteriophages present at very low abundance and low frequencies across the three cohorts. Lambdavirus lambda was detected in 14% of UK and 11% of Bangladeshi samples but was absent in South African samples. Papiine betaherpesvirus 3 was identified in 62.5% of South African placentas. Punavirus (29.1%) and Streptococcus phages (16.67%) were also prevalent in South African samples. A variety of bacterial species including Moraxella osloensis, Delftia lacustris, Cutibacterium acnes, Escherichia coli and Staphylococcus epidermidis were detected in samples across the three cohorts in variable frequencies but without any notable tissue immune responses. None of the viruses or bacteria exhibited associations with PTB, except D. lacustris, which was significantly more abundant in preterm compared to term placentas in the Bangladeshi cohort. We conclude that the human placenta harbours a virome predominated by bacteriophages and that subclinical viral infection in spontaneous PTB is rare.

Demographic studies have revealed a strong association between exposure to high ambient temperatures during pregnancy and increased risks of preterm birth (PTB). The mechanism underlying this association is unclear, but it is plausible that altered placental function may contribute to it. In this study, we conducted differential gene expression analysis, gene set enrichment analysis (GSEA), and gene ontology (GO) analysis on bulk RNA-seq data from human placentas delivered at term and preterm during the warmer months compared to placentas delivered at term and preterm during the colder months in the UK. We detected 48 differentially expressed genes in preterm placentas delivered during the warmer months compared to preterm placentas delivered during the colder months, the majority of which were inflammatory cytokines and chemokines, including SERPINA1, IL1B, CCL3, CCL3L3, CCL4, CCL4L2, CCL20, and CXCL8. The GSEA positively enriched 17 signalling pathways, including the NF-κB, IL17, Toll-like receptor, and chemokine signalling pathways in preterm placentas delivered during warmer months. These results were not observed in the placentas delivered at term during the same times of the year. The GO analysis revealed several enhanced biological processes, including neutrophil, granulocyte, monocyte, and lymphocyte chemotaxis, as well as inflammatory and humoral immune responses in preterm placentas, but not in placentas delivered at term in the summer. We conclude that maternal exposure to warm environmental temperatures during pregnancy likely alters the placental transcriptomes towards inflammation and immune regulation, potentially leading to PTB.

Demographic studies have revealed a strong association between exposure to high ambient temperatures during pregnancy and increased risks of preterm birth (PTB). The mechanism underlying this association is unclear, but it is plausible that altered placental function may contribute. In this study, we conducted differential gene expression analysis, gene set enrichment analysis (GSEA), and gene ontology (GO) analysis on bulk RNA-seq data from human placentas delivered at term and preterm during the warmer months compared to placentas delivered at term and preterm during the colder months in the UK. We detected 48 differentially expressed genes in preterm placentas delivered during the warmer months compared to preterm placentas delivered during the colder months, the majority of which were inflammatory cytokines and chemokines, including SERPINA1, IL1B, CCL3, CCL3L3, CCL4, CCL4L2, CCL20, and CXCL8. The GSEA positively enriched 17 signalling pathways, including the NF-κB, IL17, toll-like receptor, and chemokine signalling pathways, in warm-exposed preterm placentas, which were not observed in warm-exposed term placentas. The GO analysis revealed several biological processes, including neutrophil, granulocyte, monocyte, and lymphocyte chemotaxis, as well as inflammatory and humoral immune responses in warm-exposed preterm placentas, but not in warm-exposed term placentas. We conclude that maternal exposure to warm environmental temperatures during pregnancy alters the placental transcriptome towards inflammation and immune regulation, potentially leading to PTB.

Damage to alveoli, the gas-exchanging region of the lungs, is a component of many chronic and acute lung diseases. In addition, insufficient generation of alveoli results in bronchopulmonary dysplasia, a disease of prematurity. Therefore visualising the process of alveolar development (alveologenesis) is critical for our understanding of lung homeostasis and for the development of treatments to repair and regenerate lung tissue. Here we show live alveologenesis, using long-term, time-lapse imaging of precision-cut lung slices. We reveal that during this process, epithelial cells are highly mobile and we identify specific cell behaviours that contribute to alveologenesis: cell clustering, hollowing and cell extension. Using the cytoskeleton inhibitors blebbistatin and cytochalasin D, we show that cell migration is a key driver of alveologenesis. This study reveals important novel information about lung biology and provides a new system in which to manipulate alveologenesis genetically and pharmacologically.

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Defence proteins produced by epithelial cells are a critical component of the host response to respiratory infection. BPIFA1/SPLUNC1 is a member of the bactericidal/permeability-increasing (BPI) fold-containing (BPIF) protein family and is secreted in the mammalian respiratory tract. While it has been implicated in airway host defence its function is yet unresolved. The objective of this study was to use system biology tools to assess SPLUNC1 function in the respiratory tract in response to Influenza A virus (IAV) infection. We have established an in vivo model for studying SPLUNC1 function using knockout mice. As early as day 1 post infection, there is a 1 log increase in IAV titre and a more rapid spread of virus. Analyses of both label-free quantitative proteomics and transcriptomics data sets show an increased infiltration of inflammatory cells in the lungs of infected SPLUNC1 KO compared with wild-type controls. This has been complemented by histopathology as well as flow cytometric analysis, which shows a 3-fold increase in neutrophils in the lungs and BAL. Pathway analyses also reveals a modulation in cell movement and humoral immune responses in the KO mice. Gene set enrichment analysis of RNAseq output shows a significantly reduced enrichment in the expression of B and T lymphocyte surface markers in KO mice compared to wild-type mice, hence identifying molecular signatures associated with SPLUNC1 action. Our data indicate that SPLUNC1 is a crucial component of the mucosal host defence against Influenza A virus and provide further support for its function in influencing inflammation and adaptive immunity.

The tissue turnover of unperturbed adult lung is remarkably slow. However, after injury or insult, a specialised group of facultative lung progenitors become activated to replenish damaged tissue through a reparative process called regeneration. Disruption in this process results in healing by fibrosis causing aberrant lung remodelling and organ dysfunction. Post-insult failure of regeneration leads to various incurable lung diseases including chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis. Therefore, identification of true endogenous lung progenitors/stem cells, and their regenerative pathway are crucial for next-generation therapeutic development. Recent studies provide exciting and novel insights into postnatal lung development and post-injury lung regeneration by native lung progenitors. Furthermore, exogenous application of bone marrow stem cells, embryonic stem cells and inducible pluripotent stem cells (iPSC) show evidences of their regenerative capacity in the repair of injured and diseased lungs. With the advent of modern tissue engineering techniques, whole lung regeneration in the lab using de-cellularised tissue scaffold and stem cells is now becoming reality. In this review, we will highlight the advancement of our understanding in lung regeneration and development of stem cell mediated therapeutic strategies in combating incurable lung diseases.