Glial Fibrillary Acidic Protein-Expressing Glia in the Mouse Lung

Abstract

Autonomic nerves regulate important functions in visceral organs, including the lung. The postganglionic portion of these nerves is ensheathed by glial cells known as non-myelinating Schwann cells. In the brain, glia play important functional roles in neurotransmission, neuroinflammation, and maintenance of the blood brain barrier. Similarly, enteric glia are now known to have analogous roles in gastrointestinal neurotransmission, inflammatory response, and barrier formation. In contrast to this, very little is known about the function of glia in other visceral organs. Like the gut, the lung forms a barrier between airborne pathogens and the bloodstream, and autonomic lung innervation is known to affect pulmonary inflammation and lung function. Lung glia are described as non-myelinating Schwann cells but their function is not known, and indeed no transgenic tools have been validated to study them in vivo. The primary goal of this research was, therefore, to investigate the relationship between non-myelinating Schwann cells and pulmonary nerves in the airways and vasculature and to validate existing transgenic mouse tools that would be useful for studying their function. We focused on the glial fibrillary acidic protein promoter, which is a cognate marker of astrocytes that is expressed by enteric glia and non-myelinating Schwann cells. We describe the morphology of non-myelinating Schwann cells in the lung and verify that they express glial fibrillary acidic protein and S100, a classic glial marker. Furthermore, we characterize the relationship of non-myelinating Schwann cells to pulmonary nerves. Finally, we report tools for studying their function, including a commercially available transgenic mouse line.

Immunofluorescent characterization of non-myelinating Schwann cells and their interactions with immune cells in mouse mesenteric lymph node

“… 32 Moreover, GFAP-cre mice have been utilized as a powerful tool for studying NMSCs, and the colocalization of GFAP-GFP/ S100 has also demonstrated the reliability of GFAP as a suitable marker for NMSCs. 33 Furthermore, no convincing evidence of the expression of GFAP in myelinating Schwann cells has been observed. 33 Therefore, anti-GFAP antibodies can be utilized as a suitable marker for NMSCs.…”

“… 33 Furthermore, no convincing evidence of the expression of GFAP in myelinating Schwann cells has been observed. 33 Therefore, anti-GFAP antibodies can be utilized as a suitable marker for NMSCs. 32 , 33 …”

“…The rabbit polyclonal antibody from DAKO has been used extensively to study glial cells within both the CNS and PNS. 6 , 29 , 33 We have applied this antibody for immunofluorescent staining in a variety of tissues including brain, lung, trachea, skin, intestine, spleen, and lymph nodes. We observed brightly stained cells with astrocyte morphology in the brain and what would be expected for the morphology and distribution for NMSCs in these tissues (except for the lymph node, other data not shown here).…”

“…In the present study, the interaction of NMSCs and immune cells inside the lymph node has been extensively studied in situ , and our results raise a few interesting points. First, since NMSCs are essential components of Remak fibers, and as recent studies have demonstrated the close association of NMSC and various nerve fibers, 15 , 33 the local interaction of NMSC processes and immune cells ( e.g ., DCs and macrophages) may indicate the local interaction of nerve fibers and these immune cells. Secondly, as Schwann cells can be considered as important glial cells that provide life support for axons 41 and that play important roles in the degeneration/regeneration of axons, 16 the local interactions suggest that NMSCs may have effects on the innate/adaptive immune response and vice versa.…”

Schwann Cells Augment Cell Spreading and Metastasis of Lung Cancer

“…Since the initial description of SCs in the lungs of cats (27) and further demonstrations of a close association between SCs and axons of the pulmonary nerves in various vertebrates (28,29), there are still no reports describing the participation of PNS neuroglial cells in lung cancer development or progression. Early descriptions of lung SCs were based on the electron microscopy, while the more recent studies utilized IHC with the glia-specific markers S100B (or S100b) and GFAP (29). Using another SC marker, the low-affinity NGF receptor (also known as p75 neurotrophin receptor, p75 NTR ), we have developed an immunofluorescence staining to demonstrate the presence of SCs in the murine lungs.…”