Correlation of blood protein levels and vaginal microbiota abundance in participants of a 5-day dry immersion experiment

Introduction. Recently, women have increasingly participated both in ground-based model experiments simulating specific spaceflight factors and in actual space missions. During spaceflight, the human body is exposed to various factors that may pose health risks. When modeling various spaceflight factors, the human microbiota undergoes adverse changes: the proportion of opportunistic microorganisms increases, while the abundance of protective microorganisms decreases. Pronounced changes also occur in the blood protein profile. The relevance of this study is due to the close relationship between the blood protein profile and the composition of the vaginal microbiota; disruptions in the microbiota can affect protein metabolism and biochemical parameters of the body, provoking the development of pathologies.

Objective. To identify the relationship between the blood proteome and the bacteria of the vaginal biotope in participants of a 5-day dry immersion experiment.

Materials and methods. Seven female volunteers of reproductive age (mean age 29 ± 1 years) participated in the dry immersion study. The participants did not receive antibacterial treatment during the experiment. The subjects were divided into two groups: the L + P group (n = 3) consumed a lactoferrin-based drink (200 mg/day) together with intravaginal glucose-based placebo suppositories; the P + P group (n = 4) consumed a placebo preparation (200 mg glucose) and intravaginal maltodextrin placebo suppositories (200 mg/day). Vaginal and endocervical swab samples were collected twice: before the start of the experiment and 5–7 days after its completion, with smear collection synchronized to days 19–22 of the menstrual cycle. For each participant, vaginal smear microscopy was performed, and microorganisms were identified to species level using MALDI-TOF MS analysis. Blood samples for proteomic analysis were examined by liquid chromatography and mass spectrometry. Statistical analysis was performed using STATISTICA 12.0. The STRING.DB platform was used to identify clusters among the proteins extracted from factor analysis.

Results. Proteomic analysis of dried blood spot extracts allowed identification of 818 distinct proteins. Using factor analysis before the start of dry immersion, seven factors were extracted (according to the Kaiser–Meyer–Olkin criterion, only data with KMO ≥ 0.7, indicating acceptable, good, or excellent suitability for factor analysis, were included). Analysis of the extracted factors showed that before dry immersion, the association between blood proteins and bacteria was determined by the following processes: ubiquitination (37.9% of variance), immune responses (12.3% of variance), and hormonal status (13.7% of variance). After completion of the experiment, the key processes in the protein-bacterium relationship became ubiquitination (37.1% of variance in the P + P group), immune mechanisms (43.88% of variance in the L + P group), and estradiol synthesis (56.12% and 33.5% of variance in the L + P and P + P groups, respectively). The following microorganisms showed the greatest sensitivity to proteins associated with estradiol: Lactobacillus spp., Corynebacterium spp., Staphylococcus spp., and Cutibacterium spp.

Conclusions. Before and after dry immersion, the interaction between blood proteins and bacteria was determined by ubiquitination and immune processes. After the experiment, the relationship within the protein-bacterium system became stronger, and the microorganisms most sensitive to proteins involved in estradiol processing were representatives of Lactobacillus spp., Corynebacterium spp., Staphylococcus spp., and Cutibacterium spp. This suggests the possibility of strengthening the colonization resistance of the vaginal microbiota through targeted modulation of specific biological processes in the body.

1. Ogunrinola GA, Oyewale JO, Oshamika OO, Olasehinde GI. The human microbiome and its impacts on health. International Journal Microbiology. 2020:8045646. https://doi.org/10.1155/2020/8045646

2. LaPelusa A, Kaushik R. Physiology, Proteins. Treasure Island: StatPearls Publishing; 2026.

3. Kutsenko II, Borovikov IO, Kravtsova EI, Avakimyan AA, Borovikova OI, Andreyeva AA. Changes in the vaginal microbial landscape during complex treatment of mixed recurrent vaginal infections. Obstetrics and Gynecology. 2024;3:153–62 (In Russ.). https://doi.org/10.18565/aig.2024.67

4. Ciccodicola A, Casamassimi A, Rienzo M. Transcriptional regulation and its misregulation in human diseases: recent progress. International Journal of Molecular Sciences. 2025;26:9941. https://doi.org/10.3390/ijms26209941

5. Byrne EH, Farcasanu M, Bloom SM, Xulu N, Xu J, Hykes BL, et al. Antigen presenting cells link the female genital tract microbiome to mucosal inflammation, with hormonal contraception as an additional modulator of inflammatory signatures. Frontiers in Cellular and Infection Microbiology. 2021;11:733619. https://doi.org/10.3389/fcimb.2021.733619

6. Komissarova DV, Ilyin VK, Usanova NA, Morozova YuA, Priputhevich TV, Muravieva VV, et al. The state of the vaginal and cervical canal microbiota of women participating in isolation experiments of varying duration. Aerospace and Environmental Medicine. 2023;57(6):52–7 (In Russ.). https://doi.org/10.21687/0233-528X-2023-57-6-52-57

7. Komissarova D, Ilyin V, Usanova N, Goldman I, Sadchikova E, Morozova J, et al. The effect of space flight factors on the correction disorders of the vaginal and cervical microflora in ground-based models. ASSA. 2024;24(2):219–31.

8. Tomilovskaya E, Shigueva T, Sayenko D, Rukavishnikov I, Kozlovskaya I. Dry immersion as a ground-based model of microgravity physiological effects. Frontiers in Physiology. 2019;10:284. https://doi.org/10.3389/fphys.2019.00284

9. Ankirskaya AS, Muravyova VV. Integral assessment of the vaginal microbiota state. Diagnosis of opportunistic vaginitis. Obstetrics and Gynecology: News, Opinions, Training. 2020;8(1):69–76 (In Russ.).

10. Kashirinа D, Brzhozovskiy A, Sun W, Pastushkova LKh, Popova OV, Rusanov VB, et al. Proteomic characterization of dry blood spots of healthy women during simulation the microgravity effects using dry immersion. Frontiers in Physiology. 2022;12:75329. https://doi.org/10.3389/fphys.2021.753291

11. Meier F, Brunner AD, Koch S, Cox J, Rather O, Mann M, et al. Online Parallel Accumulation–Serial Fragmentation (PASEF) with a novel trapped ion mobility mass spectrometer. Molecular Cell. Proteomics. 2018;17(12):2534–45. https://doi.org/10.1074/mcp.TIR118.000900

12. Kulaichev AP. Methods and tools of complex statistical data analysis: a tutorial. 5th ed. Moscow: INFRA-M; 2017 (In Russ.).

13. Gashev SN, Betlyaeva FKh, Lupinos MYu. Mathematical methods in biology. Analysis of biological data in the STATISTICA system. Moscow: Yurait; 2022 (In Russ.).

14. Curcio-Morelli C, Zavacki AM, Christofollete M, Gereben B, de Freitas BGG, Harney JW, et al. Deubiquitination of type 2 iodothyronine deiodinase by von Hippel–Lindau protein–interacting deubiquitinating enzymes regulates thyroid hormone activation. The Journal of Clinical Investigation. 2003;112(2):189–96. https://doi.org/10.1172/JCI18348

15. Feng H, Tan J, Deng Z. Decoding plant adaptation: deubiquitinating enzymes UBP12 and UBP13 in hormone signaling, light response, and developmental processes. Journal of Experimental Botany. 2024;75(3):721–32. https://doi.org/10.1093/jxb/erad429

16. Culver JA, Li X, Jordan M, Mariappan M. A second chance for protein targeting/folding: ubiquitination and deubiquitination of nascent proteins. Bioessays. 2022;44(6):e2200014. https://doi.org/10.1002/bies.202200014

17. Zeng M, Wei X, He Y, Yang Y. Ubiquitin-specific protease 11-mediated CD36 deubiquitination acts on C1q/TNF-related protein 9 against atherosclerosis. ESC Heart Failure. 2023;10(4):2499–509. https://doi.org/10.1002/ehf2.14423

18. Kamura T, Sato S, Haque D, Liu L, Kaelin WC, Conaway RC, et al. The Elongin BC complex interacts with the conserved SOCS-box motif present in members of the SOCS, ras, WD-40 repeat, and ankyrin repeat families. Genes & Development. 1998;12(24):3872–81. https://doi.org/10.1101/gad.12.24.3872

19. Hakim S, Craig JM, Koblinski JE, Clevenger CV. Inhibition of the activity of cyclophilin A impedes prolactin receptor-mediated signaling, mammary tumorigenesis, and metastases. iScience. 2020;23(10):101581. https://doi.org/10.1016/j.isci.2020.101581

20. Brouwer de Koning IM, Lemson A, Renders NHM, Bessems M, Nooijen PTGA, Draaisma WA, et al. Inflammatory granulomatous mastitis caused by Corynebacterium kroppenstedtii: A clinical challenge: Challenge of C. kroppenstedtii induced mastitis. Clinical Infection in Practice. 2022;15;100147. https://doi.org/10.1016/j.clinpr.2022.100147

21. Zhang J, Sun Z, Jiang S, Bai X, Ma C, Peng Q, et al. Probiotic Bifidobacterium lactis V9 regulates the secretion of sex hormones in polycystic ovary syndrome patients through the gut-brain axis. mSystems. 2019;4(2):e00017–19. https://doi.org/10.1128/msystems.00017-19

22. Horn CM, Kielian T. Crosstalk between Staphylococcus aureus and innate immunity: focus on immunometabolism. Frontiers in Immunology. 2021;11:621750. https://doi.org/10.3389/fimmu.2020.621750

23. Komissarova DV, Kashirina DN, Pastushkova LKh et al. Relationship between blood protein levels in a 3-day “dry” immersion and the number of microorganisms in the vaginal biotope and cervical canal biotope. Aerospace and Environmental Mediicne. 2025;59(3):46–56 (In Russ.). https://doi.org/10.21687/0233-528X-2025-59-3-46-56

24. Permadi W, Ritonga MA, Bayuaji H, Heija N, Khoirunnisa CD, Djuwantono T. Relationship between estradiol and hemostasis determined through thromboelastography profile in controlled ovarian stimulation cycles. Journal of Blood Medicine. 2021;12:361–8. https://doi.org/10.2147/JBM.S293434

25. Coleman JR, Moore EE, Schmitt L, Hansen K, Dow N, Freeman K, et al. Estradiol provokes hypercoagulability and affects fibrin biology: A mechanistic exploration of sex dimorphisms in coagulation. Journal of Trauma and Acute Care Surgery. 2023;94(2):179–86. https://doi.org/10.1097/TA.0000000000003822

26. Kondakova IV, Shashova EE, Sidenko EA, Astakhova TM, Zakharova LA, Sharova NP. Estrogen receptors and ubiquitin proteasome system: mutual regulation. Biomolecules. 2020;10(4):500. https://doi.org/10.3390/biom10040500

27. Komissarova DV, Ilyin VK, Markin AA, Zhuravleva OA, Vorontsov AL. Correlation between hormone levels and count of microorganisms in the vagina of women that participated in a 5-day dry immersion experiment. Human Physiology. 2025;51:57–67. https://doi.org/10.1134/S0362119725700392

28. Kalaycı-Yüksek F, Gümüş D, Güler V, et al. Progesterone and Estradiol alter the growth, virulence and antibiotic susceptibilities of Staphylococcus aureus. The New Microbiologica. 2023;46(1):43–51.

29. Jesse FFA, Odhah MN, Abba Y, Garba B, Mahmood Z, Hambali IU, et al. Responses of female reproductive hormones and histopathology in the reproductive organs and associated lymph nodes of Boer does challenged with Corynebacterium pseudotuberculosis and its immunogenic corynomycolic acid extract. Microbial Pathogenesis. 2020;139:103852. https://doi.org/10.1016/j.micpath.2019.103852

30. Poole RK, Pickett AT, Oliveira Filho RV, de Melo GD, Palanisamy V, Chitapilly Dass S, et al. Shifts in uterine bacterial communities associated with endogenous progesterone and 17β-estradiol concentrations in beef cattle. Domestic Animal Endocrinology. 2023;82:106766. https://doi.org/10.1016/j.domaniend.2022.106766

31. Kiseleva AA, Solovyeva TV, Ovcharova MA, Geras’kina OV, Mart’yanov SV, Cherduntseva TA, et al. Effect of β-Estradiol on mono- and mixed-species biofilms of human commensal bacteria Lactobacillus paracasei AK508 and Micrococcus luteus C01 on different model surfaces. Coatings. 2022;12:436. https://doi.org/10.3390/coatings12040436

32. Clabaut M, Suet A, Racine PJ, Tahrioui A, Verdon J, Barreau M, et al. Effect of 17β-estradiol on a human vaginal Lactobacillus crispatus strain. Scientific Reports. 2021;11(1):7133. https://doi.org/10.1038/s41598-021-86628-x

33. Li S, Li Y, Sui D, Ren Q, Ai C, Li M, et al. Anti-Inflammatory Effects of Novel Probiotic Lactobacillus rhamnosus RL-H3-005 and Pedicoccus acidilactici RP-H3-006: In Vivo and In Vitro Evidence. Foods. 2024;13:3676. https://doi.org/10.3390/foods13223676

34. Xiu H, Peng Y, Huang X, Gong J, Yang J, Cai J, et al. Neddylation alleviates methicillin-resistant Staphylococcus aureus infection by inducing macrophage reactive oxygen species production. The Journal of Immunology. 2021;207(1):296–307. https://doi.org/10.4049/jimmunol.2001167

35. Bojang E, Ghuman H, Kumwenda P, Hall RA. Immune sensing of Candida albicans. Journal of Fungi. 2021;7(2):119. https://doi.org/10.3390/jof7020119

36. Kalia N, Singh J, Kaur M. Immunopathology of recurrent vulvovaginal infections: new aspects and research directions. Frontiers in Immunology. 2019;10:2034. https://doi.org/10.3389/fimmu.2019.02034

37. Yao J, Sterling K, Wang Z, Zhang Y, Song W. The role of inflammasomes in human diseases and their potential as therapeutic targets. Signal Transduction and Targeted Therapy. 2024;9:10. https://doi.org/10.1038/s41392-023-01687-y

38. Cheng T, Wu L, Tao J, Tu S, Fan X, Wang Y, et al. Natural Human Antimicrobial Peptides and Female Reproductive Tract Infections. Archiv der Pharmazie. 2025;358;e70008. https://doi.org/10.1002/ardp.70008

39. Dong M, Dong Y, Bai J, Li H, Ma X, Li B, et al. Interactions between microbiota and cervical epithelial, immune, and mucus barrier. Frontiers in Cellular and Infection Microbiology. 2023;13:1124591. https://doi.org/10.3389/fcimb.2023.1124591

40. Hong L, Liang H, Man W, Zhao Y, Guo P. Estrogen and bacterial infection. Frontiers in Immunology. 2025;16:1556683. https://doi.org/10.3389/fimmu.2025.1556683

41. Vera-Cruz A, Tanphalchitr N, Angerl JB. Antimicrobial peptide, ll-37, and its potential as an anti-HIV agent. Clinical and Investigative Medicine. 2021;44(3);E64–71. https://utppublishing.com/doi/pdf/10.25011/cim.v44i3.36657

42. Voinova VV, Zhuikov VA, Zhuikova YV, Sorokina AA, Makhina TK, Bonartseva GA, et al. Adhesion of Escherichia coli and Lactobacillus fermentum to films and electrospun fibrous scaffolds from composites of poly(3-hydroxybutyrate) with magnetic nanoparticles in a low-frequency magnetic field. International Journal of Molecular Sciences. 2024;25:208. https://doi.org/10.3390/ijms25010208

43. Duche RT, Jaspreet J, Anamika S, Sangwan V, Sihag MK, Nwagu TNT, et al. Surface properties and potential immunomodulatory effects of candidate probiotic lactobacilli for gastrointestinal applications. Advanced Gut & Microbiome Research. 2025;7768975:18. https://doi.org/10.1155/agm3/7768975

44. Johnson JA, Delaney LF, Ojha V, Rudraraju M, Hintze KR, Siddiqui NY, et al. Commensal urinary lactobacilli inhibit major uropathogens in vitro with heterogeneity at species and strain level. Frontiers in Cellular and Infection Microbiology. 2022;12:870603. https://doi.org/10.3389/fcimb.2022.870603

45. Batoni G, Kaya E, Catelli E, Quinti S, Botti M, De Carli A, et al. Lactobacillus probiotic strains differ in their ability to adhere to human lung epithelial cells and to prevent adhesion of clinical isolates of Pseudomonas aeruginosa from cystic fibrosis lung. Microorganisms. 2023;11:1707. https://doi.org/10.3390/microorganisms11071707

46. Gladysheva IV, Cherkasov SV. Corynebacteria of the vaginal microbiome — potential pathogens or promising probiotics? BONTS UrO RAN. 2019;3 (In Russ.).

47. Chen X, Zhao X, Chen L, Zeng W, Xu H, et al. Vaginitis caused by Corynebacterium amycolatum in a prepubescent girl. Journal of Pediatric & Adolescent Gynecology. 2015;28(6):165–7. https://doi.org/10.1016/j.jpag.2015.03.008

48. Sá S, Fernandes R, Gestoso Á, Macedo JM. Cutibacterium acnes dysbiosis: alternative therapeutics for clinical application. Appleid Sciences. 2023;13:12086. https://doi.org/10.3390/app132112086