**5. Conclusions**

This research work aims to close small gaps in the sequence events on the onset of vascular lesion at the basis of various cardiovascular diseases, such as atherosclerosis.

The hypothesis we followed is the establishment of a first inflammatory condition due to physical and environmental state (diet and sport exercise habits, health conditions, etc.), and the results we obtained seem to positively correlate with the onset of a pathological state: (i) alteration of the endothelial barrier properties (i.e., membrane permeability); (ii) increase of HA in the pericellular coat and therefore of the monocyte recruitment possibility from blood; (iii) alteration of the sulfation pattern of membrane-bound HS which can cause modifications of the endothelium response to growth factor and cytokines, as well as of the lipid metabolism through the association HS/PCSK9/LDL-receptor; (iv) HAS3 enzymes abundantly decrease in these conditions without affecting the HA amount, which suggests a different role in the cell behaviour.

Concluding, we can assess that inflammation is the leading event of CVD and that it is of pivotal importance to understand if the inflammatory HS carries specific sequences connected to the various events and unravel the role of HAS3 in endothelial cells.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/10 .3390/biom11060809/s1, Figure S1: MTT vitality assay. Figure S2: Wound healing assay of HUVEC. Figure S3: Expression levels of Syndecan chains biosynthetic enzymes. Figure S4: GAGs quantification.

**Author Contributions:** Conceptualization, M.V. and A.P. (Alberto Passi); methodology, E.C., P.M., I.C. (Ilaria Caon); investigations, E.C. and J.C.; writing—original draft preparation, E.C. and M.V.; writing—review and editing: D.V. and I.C. (Ilaria Caon); critical review, E.C., A.P. (Arianna Parnigoni) and I.C. (Ilaria Canobbio).; supervision and project administration, M.V.; funding acquisition, A.P. (Alberto Passi), M.V. and E.K. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by PRIN2017 to E.K. (prot. 2017T8CMCY), FAR-University of Insubria, and EU grant RISE-HORIZON 2020 (ID645756) to A.P.

**Acknowledgments:** E.C. was a PhD student of the "Biotechnology, Biosciences, and Surgical Technology" course at Università degli Studi dell'Insubria; Ar.P. is a PhD student of the "Life Science and Biotechnology" course at Università degli Studi dell'Insubria.

**Conflicts of Interest:** The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
