Turk J Immunol. 2022; 10(2): 102-114 | DOI: 10.4274/tji.galenos.2022.92485

The Hypoxia Affects the Main Thymocyte Subset Distributions in Congenital Heart Diseases

Ekaterina Orlova¹, Olga Loginova¹, Natalia Loginova², Roman Shekhmametyev³, Sergey Shirshev^1
1Laboratory of Immunoregulation, Рerm Federal Research Center, Ural Branch of the Russian Academy of Sciences, Perm, Russia
²Medical Faculty, Perm State Medical University Named After Academician E. A. Wagner, Perm, Russia
³Cardiac Surgery Department of Federal Center for Cardiovascular Surgery Named After S. G. Sukhanov, Perm, Russia

Objective: Congenital heart diseases (CHD) are often associated with thymus development disorders and immune dysfunctions. However, the features of thymocyte differentiation in cyanotic and acyanotic CHD remain unknown.
Materials and Methods: We have analyzed the main thymocyte subsets depending on CD4 and CD8 co-expression, and the number of natural regulatory T-cells (nTreg) and invariant natural killer T-cells (iNKT) precursors in the co-cultures of thymocytes with thymic plasmacytoid (p) dendritic cells (DCs) in vitro, isolated from the thymus of children with acyanotic (without hypoxia) and cyanotic (with severe hypoxia) CHD.
Results: In the thymocyte co-cultures with pDCs in cyanotic CHD, compared to acyanotic CHD, a decreased number of thymocytes expressing αβ chains of the T-cell receptor with CD4 and CD8 lower levels (CD4loCD8loαβTCR+), but the increased numbers of CD4hiCD8-/loαβTCR+ cells were detected. The numbers of CD4-CD8-αβTCR+, CD4hiCD8hiαβTCR+, CD4-/loCD8hiαβTCR+ cells did not differ between cyanotic or acyanotic CHD. In cyanotic CHD in the thymocyte co-cultures with pDCs, the decreased number of CD4+CD25+FOXP3+ cells, nTreg precursors, was detected in comparison with acyanotic CHD. In cyanotic CHD, the number of CD3hiVα24Jα18+ cells, iNKT precursors, in the thymocyte co-cultures with pDCs did not differ in comparison with acyanotic CHD. Hypoxia in cyanotic CHD increased the resistance to apoptosis of thymocytes in co-cultures with pDCs in comparison with acyanotic CHD. Conclusion: Thus, hypoxia affected the main CD4+ and CD8+ αβTCR T-cell subsets and the number of CD4+CD25+FOXP3+ cells in the thymocyte co-cultures with pDCs isolated from thymus of children with CHD.

Keywords: Congenital heart diseases, hypoxia, thymocytes, iNKT, nTreg, pDCs

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Hipoksi Konjenital Kalp Hastalýklarýnda Ana Timosit Alt Grup Daðýlýmlarýný Etkilemektedir

Ekaterina Orlova¹, Olga Loginova¹, Natalia Loginova², Roman Shekhmametyev³, Sergey Shirshev^1
1Laboratory of Immunoregulation, Рerm Federal Research Center, Ural Branch of the Russian Academy of Sciences, Perm, Russia
²Medical Faculty, Perm State Medical University Named After Academician E. A. Wagner, Perm, Russia
³Cardiac Surgery Department of Federal Center for Cardiovascular Surgery Named After S. G. Sukhanov, Perm, Russia

Amaç: Konjenital kalp hastalýklarý (KKH) sýklýkla timus geliþim bozukluklarý ve immün fonksiyon bozukluklarý ile iliþkilidir. Bununla birlikte, siyanotik ve asiyanotik KKH’de timosit farklýlaþmasýnýn özellikleri halen bilinmemektedir.
Gereç ve Yöntem: CD4 ve CD8 ko-ekspresyonuna baðlý olarak asiyanotik (hipoksisiz) ve siyanotik (þiddetli hipoksili) KKH’li çocuklarýn timüsünden izole edilen, ana timosit alt kümelerini ve timik plazmasitoid (p) dendritik hücreler (DH’ler) ile timositlerin ko-kültürlerinde doðal regülatör T-hücreleri (nTreg) ve deðiþmez doðal öldürücü T-hücreleri (iNKT) prekürsörlerinin miktarlarýný in vitro olarak analiz edildi. Bulgular: Siyanotik KKH’de pDH’li timosit ko-kültürlerinde, asiyanotik ile karþýlaþtýrýldýðýnda, daha düþük seviyelerde CD4 ve CD8 ile T-hücresi reseptörünün (THR) αβ zincirlerini eksprese eden timosit sayýsýnda azalma tespit edildi (CD4loCD8loaβTHR+), ancak artan sayýda CD4hiCD8-/loαβTHR+ hücreleri bulundu. CD4-CD8-αβTHR+, CD4hiCD8hiαβTHR+, CD4-/loCD8hiαβTHR+ hücrelerinin sayýsý açýsýndan siyanotik veya asiyanotik KKH arasýnda farklýlýk görülmedi. pDH’li timosit ko-kültürlerinde siyanotik KKH’de, asiyanotik KKH ile karþýlaþtýrýldýðýnda CD4+CD25+FOXP3+ hücrelerinin, nTreg prekürsörlerinin sayýsýnda azalma tespit edildi. Siyanotik KKH’de, pDH’li timosit ko-kültürlerinde iNKT prekürsörleri olan CD3hiVα24Jα18+ hücrelerinin sayýsý, asiyanotik KKH ile karþýlaþtýrýldýðýnda farklýlýk göstermedi. Siyanotik KKH’deki hipoksi, asiyanotik KKH’ye kýyasla pDH’li ko-kültürlerde timositlerin apoptoza direncini artýrdý.
Sonuç: Bu nedenle hipoksi, KKH’li çocuklarýn timüsünden izole edilen pDH’ler ile timosit ko-kültürlerindeki ana CD4 ve CD8 αβTHR T-hücresi alt kümelerini ve CD4+CD25+FOXP3+ hücrelerinin sayýsýný etkilemiþtir.

Anahtar Kelimeler: Konjenital kalp hastalýklarý, hipoksi, timositler, iNKT, nTreg, pDH’ler

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