Identification of LRP1+CD13+ human periosteal stem cells that require LRP1 for bone repair.

Human periosteal skeletal stem cells (P-SSCs) are critical for cortical bone maintenance and repair. However, their in vivo identity, molecular characteristics, and specific markers remain unknown. Here, single-cell sequencing revealed human periosteum contains SSC clusters expressing known SSC markers, podoplanin (PDPN) and PDGFRA.

Coevolution of RNA and protein subunits in RNase P and RNase MRP, two RNA processing enzymes.

RNase P and RNase mitochondrial RNA processing (MRP) are ribonucleoproteins (RNPs) that consist of a catalytic RNA and a varying number of protein cofactors. RNase P is responsible for precursor tRNA maturation in all three domains of life, while RNase MRP, exclusive to eukaryotes, primarily functions in rRNA biogenesis. While eukaryotic RNase P is associated with more protein cofactors and has an RNA subunit with fewer auxiliary structural elements compared to its bacterial cousin, the double-anchor precursor tRNA recognition mechanism has remarkably been preserved during evolution.

Application of Microfluidics for Bacterial Identification.

Bacterial infections continue to pose serious public health challenges. Though anti-bacterial therapeutics are effective remedies for treating these infections, the emergence of antibiotic resistance has imposed new challenges to treatment. Often, there is a delay in prescribing antibiotics at initial symptom presentation as it can be challenging to clinically differentiate bacterial infections from other organisms (e.

Targeting hippocampal neurogenesis to protect astronauts' cognition and mood from decline due to space radiation effects.

Neurogenesis is an essential, lifelong process during which neural stem cells generate new neurons within the hippocampus, a center for learning, memory, and mood control. Neural stem cells are vulnerable to environmental insults spanning from chronic stress to radiation. These insults reduce their numbers and diminish neurogenesis, leading to memory decline, anxiety, and depression.

Tendon and motor phenotypes in the mouse model of recessive osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is characterized by short stature, skeletal deformities, low bone mass, and motor deficits. A subset of OI patients also present with joint hypermobility; however, the role of tendon dysfunction in OI pathogenesis is largely unknown. Using the mouse model of severe, recessive OI, we found that mutant Achilles and patellar tendons were thinner and weaker with increased collagen cross-links and reduced collagen fibril size at 1- and 4-months compared to wildtype.

Real-Time Imaging of CCL5-Induced Migration of Periosteal Skeletal Stem Cells in Mice.

Periosteal skeletal stem cells (P-SSCs) are essential for lifelong bone maintenance and repair, making them an ideal focus for the development of therapies to enhance fracture healing.  Periosteal cells rapidly migrate to an injury to supply new chondrocytes and osteoblasts for fracture healing. Traditionally, the efficacy of a cytokine to induce cell migration has only been conducted in vitro by performing a transwell or scratch assay.

Identification of Functionally Distinct Mx1+αSMA+ Periosteal Skeletal Stem Cells.

The periosteum is critical for bone maintenance and healing. However, the in vivo identity and specific regulatory mechanisms of adult periosteum-resident skeletal stem cells are unknown. Here, we report animal models that selectively and durably label postnatal Mx1+αSMA+ periosteal stem cells (P-SSCs) and establish that P-SSCs are a long-term repopulating, functionally distinct SSC subset responsible for lifelong generation of periosteal osteoblasts.

Comparative analysis of gene expression identifies distinct molecular signatures of bone marrow- and periosteal-skeletal stem/progenitor cells.

Periosteum and bone marrow (BM) both contain skeletal stem/progenitor cells (SSCs) that participate in fracture repair. However, the functional difference and selective regulatory mechanisms of SSCs in different locations are unknown due to the lack of specific markers. Here, we report a comprehensive gene expression analysis of bone marrow SSCs (BM-SSCs), periosteal SSCs (P-SSCs), and more differentiated osteoprogenitors by using reporter mice expressing Interferon-inducible Mx1 and NestinGFP, previously known SSC markers.