During the regeneration of freshwater planarians, polarity and patterning programs play essential roles in determining whether a head or a tail regenerates at anterior or posterior-facing wounds. This decision is made very soon after amputation. The pivotal role of the Wnt/β-catenin and Hh signaling pathways in re-establishing anterior-posterior (AP) polarity has been well documented. However, the mechanisms that control the growth and differentiation of the blastema in accordance with its AP identity are less well understood. Previous studies have described a role of Smed-egfr-3, a planarian epidermal growth factor receptor, in blastema growth and differentiation. Here, we identify Smed-egr-4, a zinc-finger transcription factor belonging to the early growth response gene family, as a putative downstream target of Smed-egfr-3. Smed-egr-4 is mainly expressed in the central nervous system and its silencing inhibits anterior regeneration without affecting the regeneration of posterior regions. Single and combinatorial RNA interference to target different elements of the Wnt/β-catenin pathway, together with expression analysis of brain- and anterior-specific markers, revealed that Smed-egr-4: (1) is expressed in two phases - an early Smed-egfr-3-independent phase and a late Smed-egfr-3-dependent phase; (2) is necessary for the differentiation of the brain primordia in the early stages of regeneration; and (3) that it appears to antagonize the activity of the Wnt/β-catenin pathway to allow head regeneration. These results suggest that a conserved EGFR/egr pathway plays an important role in cell differentiation during planarian regeneration and indicate an association between early brain differentiation and the proper progression of head regeneration.
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http://dx.doi.org/10.1242/dev.101345 | DOI Listing |
Clin Adv Periodontics
January 2025
Operative Unit of Dentistry, Azienda Unità Sanitaria Locale, Ferrara, Italy.
Background: The purpose of the present case study is to describe the application of a modification of the Biologically-oriented Alveolar Ridge Preservation (BARP) principles in cases of peri-implant bone dehiscence (PIBD) due to a compromised alveolus at immediate implant placement (IIP).
Methods: The technique is based on the stratification of three layers: a deep layer with a collagen sponge (CS) in the apical part of the alveolus (where the buccal bone plate was still present) to support the blood clot; a graft layer to correct the PIBD; and a superficial collagen layer to cover the graft thus providing space and enhancing clot/graft stability. Healing was obtained by primary closure.
Sci Rep
January 2025
Central Clinical School, Faculty of Medicine and Health, The University of Sydney, Camperdown, Australia.
Osseointegration is a crucial property of biomaterials used for bone defect repair. While titanium is the gold standard in craniofacial surgeries, various polymeric biomaterials are being explored as alternatives. However, polymeric materials can be bioinert, hindering integration with surrounding tissues.
View Article and Find Full Text PDFMed Sci Monit
January 2025
Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China.
BACKGROUND The precedence effect (PE) is a physiological phenomenon for accurate sound localization in a reverberant environment. Physiological studies of PE have mostly focused on the central nucleus of the inferior colliculus (CNIC), which receives ascending and descending projections, as well as projections from the shell of the inferior colliculus (IC) and contralateral IC. However, the role of the dorsal cortex of the IC (DCIC), which receives ascending and descending projections to ensure sound information processing and conduction on PE formation, remains unclear.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
IZKF Research Group Tissue Regeneration in Musculoskeletal Diseases, University Hospital Wuerzburg, D-97070 Wuerzburg, Germany.
Immunosuppression is one key feature of mesenchymal stromal cells (MSCs) that has high expectations for therapeutic use. The influence of pro-inflammatory stimuli can modify the characteristics of MSCs and enhance immunosuppressive properties. The local postoperative environment contains cytokines, MSCs, and immune cells in high quantities, and their mutual influence is still unclear.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Oncode Institute, Hubrecht Institute-Royal Netherlands Academy of Arts and Science, Utrecht 3584 CT, The Netherlands.
Matrigel/BME, a basement membrane-like preparation, supports long-term growth of epithelial 3D organoids from adult stem cells [T. Sato , , 262-265 (2009); T. Sato , , 1762-1772 (2011)].
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