From Planarians to Mammals - the many faces of regeneration

Abstract

This report presents the history of the involvement of the Department of Cytology in studies of different aspects of regeneration. It can be divided into two major phases; the first focused on the regeneration of Turbellarians and the second on the regeneration of rat skeletal muscles including the differentiation of satellite cells in vitro. Regeneration of Turbellarians was investigated both at the cellular and molecular levels including the role of the protein kinase C (PKC) in this process. Studies on skeletal muscle regeneration initially focused on factors involved in regulation of signal transduction pathways. Next, we explored the influence of growth factors on the modulation of the regeneration process. Another important aspect of our studies was investigating of the distribution and function of different proteins involved in adhesion and fusion of myoblasts. Finally, we are also conducting research on the role of stem cells from other tissues in the regeneration of skeletal muscle. KEY WORDS: regeneration, planaria, skeletal muscleIn this report we present the history of the involvement of the Department of Cytology team in the studies on regeneration dated from 1974. This research may be divided into two major phases. First, we concentrated our efforts on the regeneration of Turbellarians. Then, in 1987, we switched our research model to the regeneration of the rat skeletal muscle and the differentiation of satellite cells in vitro. In this article we demonstrate the main topics of the studies conducted solely by the members of our group or in collaboration with other laboratories. Planarian regenerationPlanarians serve as a good model for the study of cell differentiation. Due the presence of totipotent stem cells they are characterized by an unique ability to regenerate. These stem cells (neoblasts) are responsible for the regeneration and growth. Neoblasts are true totipotent stem cells, like embryonic stem cells in vertebrates. They can be involved in the differentiation of all planarian tissues. Turbellarian of the order Catenulida were cultured in our laboratory for 6 years and served those days as a subject of various studies (Fig. 1). Our first publication in that we focused at Catenula concerned its asexual reproduction and regeneration (Moraczewski, 1977). The examination of the ultrastructure of the myodermal body wall by (Moraczewski and Czubaj, 1974) and (Soltynska et al., 1976), as well as of the nervous system by (Moraczewski et al., 1977a, Moraczewski et Int. J. Dev. Biol. 52: 219-227 (2008) ., 1977b), made it possible to trace precisely the course of regeneration and paratomy i.e. transverse fission during which differentiation of new organs occurred prior to separation from the mother animal ( Fig. 1 A,B). These studies showed that fissioning in Catenula was a typical paratomy as defined by (Wagner, 1890). The Catenula species analyzed by us always divided into only two zooids, and fission always occurred behind the intestine. The opisthe i.e. he posterior daughter org...

Functional analysis of grimp, a novel gene required for mesodermal cell proliferation at an initial stage of regeneration in Enchytraeus japonensis (Enchytraeidae, Oligochaete)

“…Connected to this, it should be mentioned that the peptide contains a possible site which is cleaved by the signal peptidase. In addition, it has been known that PKC takes part in cellular responses to various signals such as hormones and growth factors and that its phosphorylating activities are essential for numerous processes, including cell proliferation and differentiation (Moraczewski et al, 2008;Nishizuka, 1992). Although any helpful information for presumption of interaction between grimp and other genes was not obtained in the present study, the presence of many PKC phosphorylation sites may indicate that grimp may be located downstream of growth factors such as TGF-beta and FGF.…”

Mouse gastrocnemius muscle regeneration after mechanical or cardiotoxin injury

“…Just after injury, an inflammatory response takes place, followed by phagocytosis of damaged myofibers and the activation of satellite cells. Next, satellite cells start to proliferate, and fuse into myotubes that finally differentiate into myofibers [17,18]. In the current study, histological analyses were performed on intact ( Figure 1B) and regenerating muscles on the 1 st , 4 th , 6 th , and 14 th days after mechanical or CTX injury ( Figure 1C).…”

“…Crushing as a method of inducing regeneration was first described by Bassaglia and Gautron [11], and has since been used in many research studies by us www.fhc.viamedica.pl [17][18][19][20] and by others [11,16]. One of the important steps of this procedure is denervation, which not only ensures reproducibility of the process, but also makes the initial steps of regeneration less painful for the animal.…”

“…Moreover, only a few papers have included a detailed, side by side, comparison of the muscle regeneration induced using different methods, and these publications do not cover all the molecular changes occurring within the muscles [13][14][15]. To fill this gap in knowledge, we aimed to carefully compare the dynamics of regeneration induced by two types of commonly used injury methods: crushing [11,[16][17][18][19][20] and CTX injection [7,[21][22][23][24][25][26]. Crushing, accompanied by denervation, causes muscle degeneration as a result of mechanical devastation of myofibers [11].…”

The effect of paraoxon on spermatogenesis in Dugesia gonocephala from the Chilean Altiplano: proliferation and apoptosis

“…Incorporation studies with bromodeoxyuridine (BrdU) show that 99% of the neoblasts are labeled with BrdU after 3 days of continuous BrdU treatment (Lau et al 2007). The availability of BrdU-labeling for planarian stem cells, and thousands of planarian cDNA sequences are soon to be released into public databases (Robb and Sanchez 2002;Moraczewski et al 2008).…”