Laminin N-terminus α31 protein distribution in adult human tissues

Abstract

Laminin N terminus 31 (LaNt 31) is a netrin-like protein derived from alternative splicing of the laminin 3 gene. Although LaNt 31 has been demonstrated to influence corneal and skin epithelial cell function, its expression has not been investigated beyond these tissues. In this study, we used immunohistochemistry to characterise the distribution of this protein in a wide-array of human tissue sections in comparison to laminin 3. These data revealed widespread LaNt 31 expression. In epithelial tissue, LaNt 31 was present in the basal layer of the epidermis, throughout the epithelium of the digestive tract, and much of the epithelium of the reproductive system. LaNt 31 was also found throughout the vasculature of most tissues, with enrichment in reticular-like fibres in the extracellular matrix surrounding large vessels. A similar matrix pattern was observed around the terminal ducts in the breast and around the alveolar epithelium in the lung, where basement membrane staining was also evident. Specific enrichment of LaNt 31 was identified in sub-populations of cells of the kidney, liver, pancreas, and spleen, with variations in intensity between different cell types in the collecting ducts and glomeruli of the kidney being of particular note. Intriguingly, LaNt 31 immunoreactivity was also evident in neurons of the central nervous system, in the cerebellum, cerebral cortex, and spinal cord. Together these findings suggest that LaNt 31 may be functionally relevant in a wider range of tissue contexts than previously thought, and provides a valuable basis for investigation into this interesting protein.