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Currently, there are no accurate means to predict spontaneous preterm birth (SPTB). Recently, we observed low expression of alpha-1 antitrypsin (AAT) in SPTB placentas. Present aim was to compare the concentrations of maternal serum AAT in pregnancies with preterm and term deliveries. Serum C-reactive protein (CRP) was used as a reference inflammatory marker. Two populations were studied. The first population comprised women who eventually gave birth spontaneously preterm (SPTB group) or term (control group). The second population included pregnant women shortly before delivery and nonpregnant women. We observed that serum AAT levels were higher in the SPTB group than in the controls, and a similar difference was observed when serum CRP was considered in multivariable analysis. However, the overlap in the AAT concentrations was considerable. No statistical significance was observed in serum AAT levels between preterm and term pregnancies at delivery. However, AAT levels were higher at delivery compared to nonpregnant controls. We did not observe a strong correlation between serum AAT and CRP in early pregnancy samples and at labor. We propose that during early pregnancy, complicated by subsequent SPTB, modest elevation of serum AAT associates with SPTB., (© 2024. The Author(s).)

Background: Specific heat shock proteins are associated with pregnancy complications, including spontaneous preterm birth (SPTB). Placental proteomics and whole exome sequencing recently suggested an association between heat shock protein HSPA5 and uncomplicated SPTB. In the present study, we investigated the localization of and possible roles for HSPA5 in SPTB., Methods: Western blot was performed to validate the result from the previously published proteomic analysis. We used qPCR to assess mRNA expression of genes and immunohistochemistry and immunoelectron microscopy to examine localization of HSPA5 in placental tissue. We silenced the HSPA5 gene in the HTR8/SVneo human trophoblast cell line to investigate possible functions of HSPA5., Results: HSPA5 was upregulated in placentas from SPTBs compared to spontaneous term births. We did not observe upregulation of HSPA5 mRNA in placental samples. The protein was localized in placental trophoblast in both spontaneous preterm and term placentas. Gene silencing of HSPA5 in human trophoblast cell culture affected the inflammatory response and decreased the expression of several proinflammatory genes., Conclusions: We suggest that upregulation of HSPA5 in the placenta is associated with spontaneous preterm labor. HSPA5 may promote the inflammatory response and alter the anti-inflammatory state of the placenta which could eventually lead to premature labor., Impact: We validated upregulation of HSPA5 in placentas from spontaneous preterm birth. HSPA5 was not upregulated at transcriptional level which suggests that it may be regulated post-translationally. Silencing HSPA5 in a human trophoblast-derived cell line suggested that HSPA5 promotes expression of proinflammatory cytokines. The emerging inflammation could lead to spontaneous preterm labor. Identifying inflammatory pathways and factors associated with spontaneous preterm birth increases knowledge of the molecular mechanisms of premature labor. This could provide cues to predict imminent premature labor and lead to information about how to safely maintain pregnancies., (© 2023. The Author(s).)

Heat shock proteins are involved in the response to stress including activation of the immune response. Elevated circulating heat shock proteins are associated with spontaneous preterm birth (SPTB). Intracellular heat shock proteins act as multifunctional molecular chaperones that regulate activity of nuclear hormone receptors. Since SPTB has a significant genetic predisposition, our objective was to identify genetic and transcriptomic evidence of heat shock proteins and nuclear hormone receptors that may affect risk for SPTB. We investigated all 97 genes encoding members of the heat shock protein families and all 49 genes encoding nuclear hormone receptors for their potential role in SPTB susceptibility. We used multiple genetic and genomic datasets including genome-wide association studies (GWASs), whole-exome sequencing (WES), and placental transcriptomics to identify SPTB predisposing factors from the mother, infant, and placenta. There were multiple associations of heat shock protein and nuclear hormone receptor genes with SPTB. Several orthogonal datasets supported roles for SEC63, HSPA1L, SACS, RORA, and AR in susceptibility to SPTB. We propose that suppression of specific heat shock proteins promotes maintenance of pregnancy, whereas activation of specific heat shock protein mediated signaling may disturb maternal-fetal tolerance and promote labor., (© 2021. The Author(s).)