Correction: Rivas et al. Tendon-Derived Mesenchymal Stem Cells (TDSCs) as an In Vitro Model for Virological Studies in Wild Birds. 2023, , 1455.

In the original publication [...

Tendon-Derived Mesenchymal Stem Cells (TDSCs) as an In Vitro Model for Virological Studies in Wild Birds.

The use of wild animals in research is complicated due to the capture and housing conditions, as well as to legal aspects, making it difficult to develop in vivo and in vitro models for the study of pathologies that affect these species. Here we validate an in vitro model of tendon-derived mesenchymal cells (TDSC) from Eurasian blackbird () cadaveric samples. Through the expression of surface markers and the ability to differentiate into multiple lineages, the nature of the cells was confirmed.

Long term-cultured and cryopreserved primordial germ cells from various chicken breeds retain high proliferative potential and gonadal colonisation competency.

When derived from chicken embryos, avian primordial germ cells (PGCs) have been reported to keep their germline-specific properties and proliferative potential even after long-term culture and genetic modifications. Few teams to date have reported such long-term expansion and engineering without differentiation of primary avian PGCs' cultures. We have developed original and robust methods that allow more than 1 year culture, expansion and cryobanking of primary cultures of PGCs without obvious effects on their biological properties, including their ability to colonise the genital ridges.

Three-dimensional reconstruction of the pharyngeal tonsil innervation pattern in sheep.

The pharyngeal tonsil has recently been identified as a new participant in airborne contamination by the ovine scrapie agent. In the context of scrapie pathogenesis, we conducted a three-dimensional reconstruction of the innervation pattern in the lymphoid compartments of this tonsil. This model confirmed that very few nerve fibres penetrated the lymphoid follicles and suggested that the nerve fibre distribution in the interfollicular and subepithelial areas is more suitable with neuro-invasion through direct contact between these nerve fibres and prion-transporting cells prior to or after prion amplification in the germinal centre of the pharyngeal tonsil lymphoid follicles.

Neuroimmune connections in ovine pharyngeal tonsil: potential site for prion neuroinvasion.

Recent studies have established the involvement of nasal-associated lymphoid tissues, mainly the pharyngeal tonsil, in prion pathogenesis. However, the mechanisms of the associated neuroinvasion are still debated. To determine potential sites for prion neuroinvasion inside the ovine pharyngeal tonsil, the topography of heavy (200 kDa) and light (70 kDa) neurofilaments and of glial fibrillar acidic protein has been semi-quantitatively analysed inside the various compartments of the tonsil.

Features of follicular dendritic cells in ovine pharyngeal tonsil: an in vivo and in vitro study in the context of scrapie pathogenesis.

Although the alimentary tract has been suggested as the most likely portal of entry in natural scrapie, a growing amount of data indicates that the respiratory system and more specifically the pharyngeal tonsils serve as a natural portal of entry for scrapie. This study describes for the first time the broad cell populations in the lymphoid compartment of pharyngeal tonsils and more specifically inside the lymphoid follicles where the scrapie agent accumulates during the period of latency. Follicular dendritic cells (FDCs), stromal cells located in the light zone of the germinal centre of lymphoid follicles, seem to be the principal causal factor in the accumulation of the infectious agent in transmissible spongiform encephalopathy (TSE) diseases.

Transgenic engineering of male-specific muscular hypertrophy.

Using a two-step procedure involving insertional gene targeting and recombinase-mediated cassette exchange in ES cells, we have produced two lines of transgenic mice expressing a dominant-negative latency-associated myostatin propeptide under control of the myosin light chain 1F promoter and 1/3 enhancer from the TSPY locus on the Y chromosome. Males of the corresponding lines are characterized by a 5-20% increase in skeletal muscle mass. This experiment demonstrates the feasibility of a more efficient cattle production system combining superior beef production abilities for bulls and dairy abilities for cows.

Modulating skeletal muscle mass by postnatal, muscle-specific inactivation of the myostatin gene.

By using a conditional gene targeting approach exploiting the cre-lox system, we show that postnatal inactivation of the myostatin gene in striated muscle is sufficient to cause a generalized muscular hypertrophy of the same magnitude as that observed for constitutive myostatin knockout mice. This formally demonstrates that striated muscle is the production site of functional myostatin and that this member of the TGFbeta family of growth and differentiation factors regulates muscle mass not only during early embryogenesis but throughout development. It indicates that myostatin antagonist could be used to treat muscle wasting and to promote muscle growth in man and animals.