Mechanistic Links Between Gut Microbiota And Depression: Pathways, Evidence, And Therapeutic Insights

Authors

  • C. T. Nisha Rani
  • Charanjeet Singh

Keywords:

gut microbiota, depression, gut–brain axis, neurotransmitters, inflammation, HPA axis, probiotics, psychobiotics, precision psychiatry

Abstract

Depression is a complex neuropsychiatric disorder with multifactorial origins involving genetic, environmental, and physiological factors. Emerging evidence highlights the gut microbiota as a critical regulator of brain function through its bidirectional communication with the central nervous system, termed the gut–brain axis. This review critically synthesizes current mechanistic insights linking gut microbial dysbiosis to depression through alterations in neurotransmitter metabolism, immune activation, systemic inflammation, tryptophan–kynurenine pathway modulation, and hypothalamic–pituitary–adrenal (HPA) axis dysregulation. Experimental and clinical studies indicate that microbiota-derived metabolites, including short-chain fatty acids and secondary bile acids, influence neuroendocrine signaling and behavioral outcomes. Furthermore, therapeutic strategies such as probiotics, prebiotics, dietary interventions, and fecal microbiota transplantation show potential in restoring microbial homeostasis and alleviating depressive symptoms. Despite promising advances, inconsistencies across studies underscore the need for standardized methodologies, longitudinal monitoring, and mechanistic integration of multi-omic data. Collectively, these findings suggest that targeting the microbiota–gut–brain axis may open new avenues for precision psychiatry and the development of adjunctive therapies for depression

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References

1. Wang PS, Aguilar-Gaxiola S, Alonso J, Angermeyer MC, Borges G, Bromet EJ, et al. Use of mental health services for anxiety, mood, and substance disorders in 17 countries in the WHO world mental health surveys. Lancet. 2007;370(9590):841-50.

2. Angola A, Costello EJ. Depressive comorbidity in children and adolescents: empirical, theoretical, and methodological issues. Am J Psychiatry. 1993;150(12):1779-91.

3. Wittchen HU, Kessler RC, Pfister H, Höfler M, Lieb R. Why do people with anxiety disorders become depressed? A prospective-longitudinal community study. Acta Psychiatr Scand Suppl. 2000;406:14-23.

4. Beaglehole B, Mulder RT, Frampton CM, Boden JM, Newton-Howes G, Bell CJ. Psychological distress and psychiatric disorder after natural disasters: systematic review and meta-analysis. Br J Psychiatry. 2018;213(6):716-22.

5. Johannsen M, Nissen ER, Lundorff M, O’Toole MS. Mediators of acceptance and mindfulness-based therapies for anxiety and depression: a systematic review and meta-analysis. Clin Psychol Rev. 2022;94:102156.

6. Lach G, Schellekens H, Dinan TG, Cryan JF. Anxiety, depression, and the microbiome: a role for gut peptides. Neurotherapeutics. 2018;15(1):36-59.

7. Mueller NT, Bakacs E, Combellick J, Grigoryan Z, Dominguez-Bello MG. The infant microbiome development: mom matters. Trends Mol Med. 2015;21(2):109-17.

8. Ahrodia T, Das S, Bakshi S, Das B. Structure, functions, and diversity of the healthy human microbiome. Prog Mol Biol Transl Sci. 2022;191:53-82. doi:10.1016/bs.pmbts.2022.07.003

9. Silva YP, Bernardi A, Frozza RL. The role of short-chain fatty acids from gut microbiota in gut-brain communication. Front Endocrinol (Lausanne). 2020;11:25.

10. Rutsch A, Kantsjö JB, Ronchi F. The gut-brain axis: how microbiota and host inflammasome influence brain physiology and pathology. Front Immunol. 2020;11:3237.

11. Koh A, De Vadder F, Kovatcheva-Datchary P, Bäckhed F. From dietary fiber to host physiology: short-chain fatty acids as key bacterial metabolites. Cell. 2016;165(6):1332-45. doi:10.1016/j.cell.2016.05.041

12. Maes M, Kubera M, Leunis JC. The gut–brain barrier in major depression: intestinal mucosal dysfunction with an increased translocation of LPS. Neuro Endocrinol Lett. 2008;29(1):117-24.

13. Moloney RD, Desbonnet L, Clarke G, Dinan TG, Cryan JF. The microbiome: stress, health and disease. Mamm Genome. 2014;25(1-2):49-65.

14. Clarke G, Grenham S, Scully P, Fitzgerald P, Moloney RD, Shanahan F, et al. The microbiome–gut–brain axis during early life regulates the hippocampal serotonergic system in a sex-dependent manner. Mol Psychiatry. 2013;18(6):666-73.

15. Chang PV, Hao L, Offermanns S, Medzhitov R. The microbial metabolite butyrate regulates intestinal macrophage function via histone deacetylase inhibition. Proc Natl Acad Sci U S A. 2014;111(6):2247-52. doi:10.1073/pnas.1322269111

16. Louis P, Flint HJ. Formation of propionate and butyrate by the human colonic microbiota. Environ Microbiol. 2017;19(1):29-41. doi:10.1111/1462-2920.13589

17. Raqib R, Sarker P, Bergman P, Ara G, Lindh M, Sack DA, et al. Improved outcome in shigellosis associated with butyrate induction of an endogenous peptide antibiotic. Proc Natl Acad Sci U S A. 2006;103(24):9178-83. doi:10.1073/pnas.0602888103

18. Furusawa Y, Obata Y, Fukuda S, Endo TA, Nakato G, Takahashi D, et al. Commensal microbe-derived butyrate induces the differentiation of colonic regulatory T cells. Nature. 2013;504(7480):446-50. doi:10.1038/nature12721

19. Peng L, Li ZR, Green RS, Holzman IR, Lin J. Butyrate enhances the intestinal barrier by facilitating tight junction assembly via activation of AMP-activated protein kinase in Caco-2 cell monolayers. J Nutr. 2009;139(9):1619-25. doi:10.3945/jn.109.104638

20. Alli SR, Gorbovskaya I, Liu JCW, Kolla NJ, Brown L, Müller DJ. The gut microbiome in depression and potential benefit of prebiotics, probiotics and synbiotics: a systematic review of clinical trials and observational studies. Int J Mol Sci. 2022;23(8):4494.

21. Shishov VA, Kirovskaya TA, Kudrin VS, Oleskin AV. Amine neuromediators, their precursors, and oxidation products in the culture of Escherichia coli K-12. Appl Biochem Microbiol. 2009;45(5):494-7.

22. Barrett E, Ross RP, O’Toole PW, Fitzgerald GF, Stanton C. γ-Aminobutyric acid production by culturable bacteria from the human intestine. J Appl Microbiol. 2012;113(2):411-7.

23. Yano JM, Yu K, Donaldson GP, Shastri GG, Ann P, Ma L, et al. Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis. Cell. 2015;161(2):264-76.

24. Braniste V, Al-Asmakh M, Kowal C, Anuar F, Abbaspour A, Tóth M, et al. The gut microbiota influences blood-brain barrier permeability in mice. Sci Transl Med. 2014;6(263):263ra158.

25. Acharya NK, Levin EC, Clifford PM, Han M, Tourtellotte R, Chamberlain D, et al. Diabetes and hypercholesterolemia increase blood-brain barrier permeability and brain amyloid deposition: beneficial effects of the LpPLA2 inhibitor darapladib. J Alzheimers Dis. 2013;35(1):179-98.

26. Lee SW, Kim WJ, Choi YK, Song HS, Son MJ, Gelman IH, et al. SSeCKS regulates angiogenesis and tight junction formation in blood-brain barrier. Nat Med. 2003;9(7):900-6.

27. Kumar A, Pramanik J, Goyal N, Chauhan D, Sivamaruthi BS, Prajapati BG, et al. Gut microbiota in anxiety and depression: unveiling the relationships and management options. Pharmaceuticals (Basel). 2023;16(4):565. doi:10.3390/ph16040565

28. Strandwitz P. Neurotransmitter modulation by the gut microbiota. Brain Res. 2018;1693(Pt B):128-33.

29. Dinan TG, Stanton C, Cryan JF. Psychobiotics: a novel class of psychotropic. Biol Psychiatry. 2013;74(10):720-6.

30. Miller AH, Raison CL. The role of inflammation in depression: from evolutionary imperative to modern treatment target. Nat Rev Immunol. 2016;16(1):22-34.

31. Schwarcz R, Stone TW. The kynurenine pathway and the brain: challenges, controversies and promises. Neuropharmacology. 2017;112(Pt B):237-47.

32. Savitz J. Role of kynurenine metabolism pathway activation in major depressive disorders. Curr Top Behav Neurosci. 2017;31:249-67.

33. Dalile B, Van Oudenhove L, Vervliet B, Verbeke K. The role of short-chain fatty acids in microbiota–gut–brain communication. Nat Rev Gastroenterol Hepatol. 2019;16(8):461-78.

34. Chen S, Luo J, Li M, He H, Zheng P, Jiang H, et al. Altered bile acid metabolism in depression: mechanisms and therapeutic relevance. Front Pharmacol. 2021;12:646845.

35. Sudo N, Chida Y, Aiba Y, Sonoda J, Oyama N, Yu XN, et al. Postnatal microbial colonization programs the hypothalamic–pituitary–adrenal system for stress response in mice. J Physiol. 2004;558(Pt 1):263-75.

36. Foster JA, Rinaman L, Cryan JF. Stress & the gut–brain axis: regulation by the microbiome. Neurobiol Stress. 2017;7:124-36.

37. Zheng P, Zeng B, Zhou C, Liu M, Fang Z, Xu X, et al. Gut microbiome remodeling induces depressive-like behaviors through a pathway mediated by the host’s metabolism. Mol Psychiatry. 2016;21(6):786-96.

38. Valles-Colomer M, Falony G, Darzi Y, Tigchelaar EF, Wang J, Tito RY, et al. The neuroactive potential of the human gut microbiota in quality of life and depression. Nat Microbiol. 2019;4(4):623-32.

39. Messaoudi M, Violle N, Bisson JF, Desor D, Javelot H, Rougeot C. Beneficial psychological effects of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in healthy human volunteers. Gut Microbes. 2011;2(4):256-61.

40. Schmidt K, Cowen PJ, Harmer CJ, Tzortzis G, Errington S, Burnet PWJ. Prebiotic intake reduces the waking cortisol response and alters emotional bias in healthy volunteers. Psychopharmacology (Berl). 2015;232(10):1793-801.

41. Jacka FN, O’Neil A, Opie R, Itsiopoulos C, Cotton S, Mohebbi M, et al. A randomised controlled trial of dietary improvement for adults with major depression (the SMILES trial). BMC Med. 2017;15:23.

42. Cryan JF, Dinan TG. Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour. Nat Rev Neurosci. 2012;13(10):701-12.

43. Wallace CJK, Milev R. The effects of probiotics on depressive symptoms in humans: a systematic review. Ann Gen Psychiatry. 2021;20(1):22.

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Published

2025-06-05

How to Cite

1.
Nisha Rani CT, Singh C. Mechanistic Links Between Gut Microbiota And Depression: Pathways, Evidence, And Therapeutic Insights. J Neonatal Surg [Internet]. 2025 Jun. 5 [cited 2026 Apr. 30];14(31S):1116-22. Available from: https://jneonatalsurg.com/index.php/jns/article/view/9802

Issue

Vol. 14 No. 31S (2025): Journal of Neonatal Surgery

Section

Original Article

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