ABSTRACT
A previously healthy 16-year-old girl presented with a lesion on her right upper arm that initially started as a small cutaneous nodule without obvious triggers and gradually developed and enlarged to form a red-colored tumor with a hard nodule inside. What is your diagnosis?
Subject(s)
Skin Neoplasms , Adolescent , Female , Humans , Skin Neoplasms/diagnosis , Skin Neoplasms/surgery , Skin Neoplasms/pathologyABSTRACT
A man in his 60s presented with an 8-month history of pruritic papulonodular lesions on his extremities and trunk, with no significant improvement with steroids and antihistamines. What is your diagnosis?
Subject(s)
Skin Diseases , Humans , Male , Middle Aged , Skin Diseases/diagnosisABSTRACT
Autophagy, a macromolecular degradation process, plays a pivotal role in cell differentiation and survival. This study was designed to investigate the role of autophagy in the osteogenic differentiation in ligamentum fibroblasts. Rat ligamentum fibroblasts were isolated from the posterior longitudinal ligament and cultured in osteogenic induction medium. Ultrastructural analysis, immunofluorescence assay, western blot, flow cytometry, and lysosomal activity assessment were performed to determine the presence and activity of autophagy in the cells. The mineralization deposit and osteogenic gene expressions were evaluated to classify the association between autophagy activity and the bone formation ability of the spinal ligament cells. The influence of leptin and endothelin-1 on the autophagy activity was also evaluated. Our study demonstrated that autophagy was present and increased in the ligament cells under osteogenic induction. Inhibition of autophagy with either pharmacologic inhibitors (Bafilomycin A and 3-methyladenine) or Belcin1 (BECN1) knocking down weakened the mineralization capacity, decreased the gene expressions of COL1A1, osteocalcin (Ocn), and runt-related transcription factor 2 (Runx2) in the ligamentum fibroblasts and increased cell apoptosis. The Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)-BECN1 autophagic pathway was activated in the osteogenic differentiating ligamentum fibroblasts. Leptin significantly increased the autophagy activity in the ligament cells under osteogenic induction. These discoveries might improve our understanding for the mechanism of ossification of the posterior longitudinal ligament (OPLL) and provide new approaches on the prevention and treatment of this not uncommon disease.
