Functions of telocytes and controversial issues

Öz

ABSTRACT Telocytes have been identified among the interstitial/stromal cell populations in connective tissue and have attracted attention since the 2000s. These cells have been observed in the stromal compartments of various organs across different species and characteristically have long, thin cytoplasmic extensions known as ‘telopodes’. They establish an active communication network with neighboring cells and the stromal microenvironment through these specialized extensions and paracrine signaling. Intercellular signaling, mechanical support, maintenance of microenvironmental homeostasis, immune surveillance, stem cell guidance and regulation of regenerative processes are the main functions attributed to telocytes. Studies to determine organ- and tissue-specific functions are ongoing. The molecular and cellular mechanisms through which telocytes perform these functions have not yet been fully elucidated. Limitations in diagnostic and analytical methodologies, as well as commercial constraints, make telocyte research difficult. In this review, methods for histological, immunohistochemical and molecular identification of telocytes are encountered; also, current problems are discussed in telocyte research and future directions in this emerging field.

Anahtar Kelimeler

• Telocyte
• interstitial cell
• intercellular signaling
• Microenvironment

Telositlerin fonksiyonları ve tartışmalı konular

Öz

ÖZ Telositler 2000’li yıllardan bu yana dikkat çeken ve bağ dokusunda yer alan interstisyel/stromal hücre popülasyonları arasında tanımlanmaktadır. Farklı türlere ait birçok organın stromasında gözlenen bu hücreler, karakteristik olarak ‘telopod’ adı verilen ince ve uzun sitoplazmik uzantılara sahiptir. Bu özelleşmiş uzantılar aracılığıyla ve parakrin sinyalleme yoluyla komşu hücrelerle ve stromal mikroçevreyle aktif bir iletişim ağı kurmaktadır. Hücreler arası sinyal iletimi, mekanik destek, mikroçevresel homeostazın sürdürülmesi, immün gözetim, kök hücre rehberliği ve rejeneratif süreçlerin düzenlenmesi telositlere atfedilen başlıca fonksiyonlardır. Organ- ve doku-spesifik işlevlerinin belirlenmesine yönelik çalışmalar devam etmektedir. Telositlerin bu işlevleri hangi moleküler ve hücresel mekanizmalar aracılığıyla gerçekleştirdiği henüz tam olarak aydınlatılamamıştır. Tanısal ve analitik yöntemlerin sınırlılıkları ile ticari kısıtlamalar, telosit araştırmalarını güçleştirmektedir. Bu derlemede, telositlerin histolojik, immünohistokimyasal ve moleküler düzeyde tanımlanmasına yönelik yöntemler ele alınmış; ayrıca telosit araştırmalarında karşılaşılan güncel sorunlar ve geleceğe dönük araştırma hedefleri tartışılmıştır.

Anahtar Kelimeler

• Telosit
• interstisyel hücre
• hücrelerarası sinyalizasyon
• Mikroçevre

Teşekkür

Öneri ve katkılarından dolayı SANKO Üniversitesi Histoloji ve Embriyoloji Ana Bilim Dalı Öğretim Üyesi Prof. Dr. Şahin A. SIRMALI ve Gaziantep Üniversitesi Histoloji ve Embriyoloji Ana Bilim Dalı Öğretim Üyesi Prof. Dr. Mehmet YÜNCÜ hocalarıma teşekkür ederim.

Kaynakça

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