Skin is our largest organ comprising ~12% of our body weight. It is the major protective organ of the body against the environment. Over time, its protection is compromised by aging which is always associated with skin inflammation, impaired wound healing and increased risk of malignancies.

The aging phenotype develops as a result of the reduced potential for tissue regeneration concomitant with the destruction of tissue homeostasis and the accumulation of damage. Accumulation of senescent cells in tissues is the main catalyst of aging in humans. Old cells have altered gene expression profiles, highlighted by a strong increase in secreted cytokines, chemokines and extracellular proteinases.

This secretion is known as the senescence-associated secretory phenotype (SASP) and it also includes a variety of inflammatory and growth factors which act to remodel the tissue microenvironment, activate the cellular immune response and elicit an inflammatory metabolic profile. Additionally, all these changes have a negative impact on epidermal stem cells (ESC) and regeneration. Importantly, expression of the enzyme telomerase prevents cell aging and allows for the continuous maintenance of the young phenotype. In this project we will explore potential for skin regeneration and rejuvenation using cell micro-seeding technique.

We will analyse changes in the skin following an increase in proportion of young or rejuvenated healthy cells in a rat skin model and in human organotypic epidermal equivalent model. This will be achieved by introducing a large proportion (>35%, up to 55%) of young neonatal skin cells or telomerase revitalized cells using an advanced micro-transplantation technique. In this way we expect to increase the regenerative capacity of dermis and epidermis, reconstruct the youthful tissue microenvironment and extracellular matrix as well as increase ESC viability. Besides aging, various genetic disorders can disrupt protective function of the skin.

Among the most severe of such disorders is Epidermolysis bullosa (EB). EB is a heterogeneous group of hereditary skin fragility disorders caused by mutations in 18 different genes resulting in a wide range of pathologies, from mild to severe one and in extreme cases can cause death. These genes code for various skin proteins important for dermal-epidermal connections. One of the best known is Collagen VII (C7) that anchor the basal membrane. Affected animals carry mutation within the major structural (collagenous) domain of C7 which decreases the stability of C7 monomers conferring dominant-negative interference.

They have fragile and blister-prone skin showing all major signs of EB in humans. In this project we will also analyse changes in the EB rat skin following an increase in proportion of cells carrying wild type C7 and telomerase (TERT) genes. To this end we have established a protocol for micro-transplantation of cells into skin tissue which allows for manipulation of various cell populations. The main objective of this project is to directly show that it is possible to alter the cellular composition of tissues and show that by increasing the ratio of genetically corrected, healthy young or rejuvenated cells in a tissue one can alter the local tissue metabolic profile, improve maintenance of ESC in vivo and therefore increase skin healing and regeneration.

Associates

• Lucia Nanić, dr.sc., Institut Ruđer Bošković
• Andrea Cedilak, mag.ing.biotechn., Institut Ruđer Bošković
• Marija Mary Sopta, dr.sc., Institut Ruđer Bošković
• Miljenko Huzak, prof. dr.sc., Prirodoslovno - matematički fakultet Sveučilišta u Zagrebu
• Sanja Davidović Mrsić, dr.sc., dr.med., Klinički bolnički centar Zagreb
• Florian Gruber, prof.dr.sc., Medical University of Vienna, Austrija
• M. Bader, prof.dr.sc., Max-Delbruck Zentrum fur Molekulare Medizin, Berlin-Buch, Njemačka

Cosultants

• Igor Weber, prof.dr.sc., Institut Ruđer Bošković
• Ranko Stojković, dr.sc., Institut Ruđer Bošković