Genes 2023, 14, 35. https://doi.org/10.3390/genes14010035 www.mdpi.com/journal/genes Article Lasp1 Expression Is Implicated in Embryonic Development of Zebrafish Ilaria Grossi 1,† , Marco Schiavone 1,† , Elena Cannone 1 , Oana Andreea Grejdan 1 , Chiara Tobia 2 , Francesca Bonomini 3 , Rita Rezzani 3 , Alessandro Salvi 1, * and Giuseppina De Petro 1 1 Department of Molecular and Translational Medicine, Division of Biology and Genetics, University of Brescia, 25123 Brescia, Italy 2 Department of Molecular and Translational Medicine, Division of Experimental Oncology and Immunology, University of Brescia, 25123 Brescia, Italy 3 Department of Clinical and Experimental Sciences, Division of Anatomy and Physiopathology, University of Brescia, 25123 Brescia, Italy * Correspondence: alessandro.salvi@unibs.it † These authors contributed equally to this study. Abstract: The LIM and SH3 domain protein 1 (LASP1) was originally identified in metastatic breast cancer and mainly characterized as a cytoskeleton protein overexpressed in various cancer types. At present, little is known about LASP1 expression in physiological conditions, and its function during embryonic development has not been elucidated. Here, we focused on Lasp1 and embryonic development, choosing zebrafish as a vertebrate model. For the first time, we identified and determined the expression of Lasp1 protein at various stages of development, at 48 and 72 h post- fertilization (hpf), at 6 days pf and in different organs of zebrafish adults by Western blotting, 3D light-sheet microscopy and fluorescent immunohistochemistry. Further, we showed that specific lasp1 morpholino (MO) led to (i) abnormal morphants with alterations in several organs, (ii) effective knockdown of endogenous Lasp1 protein and (iii) an increase in lasp1 mRNA, as detected by ddPCR. The co-injection of lasp1 mRNA with lasp1 MO partially rescued morphant phenotypes, thus confirming the specificity of the MO oligonucleotide-induced defects. We also detected an increase in apoptosis following lasp1 MO treatment. Our results suggest a significant role for Lasp1 in embryonic development, highlighting zebrafish as a vertebrate model suitable for studying Lasp1 function in developmental biology and organogenesis. Keywords: Lasp1 expression; zebrafish model; embryonic development; apoptosis 1. Introduction In 1995, Tomasetto et al. originally identified the LIM and SH3 protein 1 (LASP1) in a c-DNA library of human breast cancer metastatic lymph nodes [1]. The human LASP1 gene, located on chromosome 17q11-21.3, encodes a polypeptide chain of 261 amino acids originally characterized as a structural cytoskeletal protein (https://www.genecards.org/cgi-bin/carddisp.pl?gene=LASP1, accessed 10 October 2022). Since then, several authors have studied LASP1 expression, at the mRNA or protein level, in different cancer types [2–8], reporting that its overexpression is inversely correlated with poor prognosis in breast and prostate cancer, medulloblastoma and hepatocellular carcinoma (HCC). Concerning HCC, we have previously shown that LASP1 mRNA is significantly overexpressed in HCC tissues, mainly in HCC developed in cirrhotic liver, and that levels of LASP1 protein and mRNA expression are comparable and increase in recurrent HCC [9]. Further, several studies have shown that LASP1 plays an important role in tumour development and metastases, and RNAi knock-down of LASP1 has led to strong inhibition of proliferation and migration in various cancer cells. Currently, it is Citation: Grossi, I.; Schiavone, M.; Cannone, E.; Grejdan, O.A.; Tobia, C.; Bonomini, F.; Rezzani, R.; Salvi, A.; De Petro, G. Lasp1 expression Is implicated in embryonic development of zebrafish. Genes 2023, 14, 35. https://doi.org/10.3390/ genes14010035 Academic Editor: Shawn Burgess Received: 7 November 2022 Revised: 9 December 2022 Accepted: 20 December 2022 Published: 22 December 2022 Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/license s/by/4.0/).