Neuro-immune modulation of the thymus microenvironment (Review)

Abstract

The thymus is the primary site for T-cell lympho-poiesis. Its function includes the maturation and selection of antigen specific T cells and selective release of these cells to the periphery. These highly complex processes require precise parenchymal organization and compartmentation where a plethora of signalling pathways occur, performing strict control on the maturation and selection processes of T lymphocytes. In this review, the main morphological characteristics of the thymus microenvironment, with particular emphasis on nerve fibers and neuropeptides were assessed, as both are responsible for neuro-immune‑modulation functions. Among several neurotransmitters that affect thymus function, we highlight the dopaminergic system as only recently has its importance on thymus function and lymphocyte physiology come to light.

Nerve fibers in the tumor microenvironment in neurotropic cancer—pancreatic cancer and cholangiocarcinoma

“…T cells originate in the thymus and then spread to peripheral organs [80]. During the process of T cell development and differentiation, neuro-immune communications in the thymus play a key role [81]. A current study reveals the distribution of nerve fibers in mouse thymus venules: there is a dense network of nerve fibers present in all thymic compartments.…”

Neuropeptides, Cytokines and Thymus Peptides as Effectors of Interactions Between Thymus and Neuroendocrine System

“…Тимус пронизан постганглионарными симпатическими норадренергическими (NA) нервны-ми волокнами [10][11][12], которые локализуются близко к крупным кровеносным сосудам, входя в кортикальную область, соприкасающуюся с тимоцитами [13][14][15]. По-мимо этого, лимфоидные органы, включая тимус, снаб-жены пептидергическими нервными волокнами, которые продуцируют ряд специфических биологически актив-ных пептидов -нейропептид Y, субстанцию Р, вазоак-тивный интестинальный пептид, опиоидные пептиды, кортикотропин-рилизинг гормон (Corticotropin-Releasing Hormone, CRH), пептид, генетически родственный кальцитонину, называемый также кальцитонин ген-родственный, или ген-кальцитониновый пептид, или ко-кальцигенин (Calcitonin Gene Related Peptide, CGRP) [1,16].…”

“…В ряде работ показаны некоторые особенности ком-плексного участия нейроэндокринной и иммунной си-стем, включая функционирование тимуса, в процессах, связанных со старением, а также с инфекционными, аутоиммунными, нейродегенеративными и онкологиче-скими заболеваниями [11,50]. Показано, что изменения иммунной системы, связанные с возрастом или заболе-ваниями, сопряжены с изменениями функционирования нервных волокон в лимфоидных органах [1].…”

Immunofluorescent Localization of Non-myelinating Schwann Cells and Their Interactions With Immune Cells in Mouse Thymus

“…4 Recent studies have demonstrated the bidirectional crosstalk/communication of the peripheral nervous system (PNS) and the lymphoid tissue/organs including the lymph node, spleen, thymus, and gut-associated lymphoid tissue (GALT). [5][6][7][8][9][10][11][12][13] The thymus is innervated by various types of nerve fibers from the PNS, suggesting neural modulation of thymic functions including T-cell development. [10][11][12][13] Sympathetic innervation originates from postganglionic neurons in the superior cervical and the stellate ganglion of the sympathetic chain.…”

“…[5][6][7][8][9][10][11][12][13] The thymus is innervated by various types of nerve fibers from the PNS, suggesting neural modulation of thymic functions including T-cell development. [10][11][12][13] Sympathetic innervation originates from postganglionic neurons in the superior cervical and the stellate ganglion of the sympathetic chain. 10 In addition, the thymus might also be innervated by parasympathetic fibers from branches of the vagus nerve, according to some reports.…”