Cryo-electron tomography pipeline for plasma membranes.

Cryo-electron tomography (cryoET) provides sub-nanometer protein structure within the dense cellular environment. Existing sample preparation methods are insufficient at accessing the plasma membrane and its associated proteins. Here, we present a correlative cryo-electron tomography pipeline optimally suited to image large ultra-thin areas of isolated basal and apical plasma membranes.

Pathophysiology of Pain and Mechanisms of Neuromodulation: A Narrative Review (A Neuron Project).

Pain serves as a vital innate defense mechanism that can significantly impact an individual's quality of life. Understanding the physiological effects of pain well plays an important role in developing novel pain treatments. Nociceptor neurons play a key role in pain and inflammation.

Cryo-electron tomography pipeline for plasma membranes.

Cryo-electron tomography (cryoET) provides sub-nanometer protein structure within the dense cellular environment. Existing sample preparation methods are insufficient at accessing the plasma membrane and its associated proteins. Here, we present a correlative cryo-electron tomography pipeline optimally suited to image large ultra-thin areas of isolated basal and apical plasma membranes.

American Society of Pain and Neuroscience Best Practice (ASPN) Guideline for the Treatment of Sacroiliac Disorders.

Clinical management of sacroiliac disease has proven challenging from both diagnostic and therapeutic perspectives. Although it is widely regarded as a common source of low back pain, little consensus exists on the appropriate clinical management of sacroiliac joint pain and dysfunction. Understanding the biomechanics, innervation, and function of this complex load bearing joint is critical to formulating appropriate treatment algorithms for SI joint disorders.

Cryo-EM structures of membrane-bound dynamin in a post-hydrolysis state primed for membrane fission.

Dynamin assembles as a helical polymer at the neck of budding endocytic vesicles, constricting the underlying membrane as it progresses through the GTPase cycle to sever vesicles from the plasma membrane. Although atomic models of the dynamin helical polymer bound to guanosine triphosphate (GTP) analogs define earlier stages of membrane constriction, there are no atomic models of the assembled state post-GTP hydrolysis. Here, we used cryo-EM methods to determine atomic structures of the dynamin helical polymer assembled on lipid tubules, akin to necks of budding endocytic vesicles, in a guanosine diphosphate (GDP)-bound, super-constricted state.

Local monomer levels and established filaments potentiate non-muscle myosin 2 assembly.

The ability to dynamically assemble contractile networks is required throughout cell physiology, yet direct biophysical mechanisms regulating non-muscle myosin 2 filament assembly in living cells are lacking. Here, we use a suite of dynamic, quantitative imaging approaches to identify deterministic factors that drive myosin filament appearance and amplification. We find that actin dynamics regulate myosin assembly, but that the static actin architecture plays a less clear role.

Local Monomer Levels and Established Filaments Potentiate Non-Muscle Myosin 2 Assembly.

The ability to dynamically assemble contractile networks is required throughout cell physiology, yet the biophysical mechanisms regulating non-muscle myosin 2 filament assembly in living cells are lacking. Here we use a suite of dynamic, quantitative imaging approaches to identify deterministic factors that drive myosin filament appearance and amplification. We find that actin dynamics regulate myosin assembly, but that the actin architecture plays a minimal direct role.

A conformational switch in clathrin light chain regulates lattice structure and endocytosis at the plasma membrane of mammalian cells.

Conformational changes in endocytic proteins are regulators of clathrin-mediated endocytosis. Three clathrin heavy chains associated with clathrin light chains (CLC) assemble into triskelia that link into a geometric lattice that curves to drive endocytosis. Structural changes in CLC have been shown to regulate triskelia assembly in solution, yet the nature of these changes, and their effects on lattice growth, curvature, and endocytosis in cells are unknown.

Dual clathrin and integrin signaling systems regulate growth factor receptor activation.

The crosstalk between growth factor and adhesion receptors is key for cell growth and migration. In pathological settings, these receptors are drivers of cancer. Yet, how growth and adhesion signals are spatially organized and integrated is poorly understood.

Resolvin D2 promotes host defense in a 2 - hit model of sepsis with secondary lung infection.

In the development of sepsis, there is early, massive inflammation which can lead to multiple organ failure. Later there is an immunosuppressed phase where the host is susceptible to secondary infections or is unable to clear existing infection. Specialized Pro-resolving Mediators (SPMs) are endogenously produced lipids which resolve infection by decreasing bacteria load and reducing systemic inflammatory response.

Sterols lower energetic barriers of membrane bending and fission necessary for efficient clathrin-mediated endocytosis.

Clathrin-mediated endocytosis (CME) is critical for cellular signal transduction, receptor recycling, and membrane homeostasis in mammalian cells. Acute depletion of cholesterol disrupts CME, motivating analysis of CME dynamics in the context of human disorders of cholesterol metabolism. We report that inhibition of post-squalene cholesterol biosynthesis impairs CME.

Single-cell transcriptomic profiling reveals distinct mechanical responses between normal and diseased tendon progenitor cells.

Regenerative medicine approaches utilizing stem cells offer a promising strategy to address tendinopathy, a class of common tendon disorders associated with pain and impaired function. Tendon progenitor cells (TPCs) are important in healing and maintaining tendon tissues. Here we provide a comprehensive single cell transcriptomic profiling of TPCs from three normal and three clinically classified tendinopathy samples in response to mechanical stimuli.

The nanoscale molecular morphology of docked exocytic dense-core vesicles in neuroendocrine cells.

Rab-GTPases and their interacting partners are key regulators of secretory vesicle trafficking, docking, and fusion to the plasma membrane in neurons and neuroendocrine cells. Where and how these proteins are positioned and organized with respect to the vesicle and plasma membrane are unknown. Here, we use correlative super-resolution light and platinum replica electron microscopy to map Rab-GTPases (Rab27a and Rab3a) and their effectors (Granuphilin-a, Rabphilin3a, and Rim2) at the nanoscale in 2D.

Concomitant Osteotomy Reduces Risk of Reoperation Following Cartilage Restoration Procedures of the Knee: A Matched Cohort Analysis.

Objective: The objective of this study is to compare the (1) reoperation rates, (2) 30-day complication rates, and (3) cost differences between patients undergoing isolated autologous chondrocyte implantation (ACI) or osteochondral allograft transplantation (OCA) procedures alone versus patients with concomitant osteotomy.

Study Design: Retrospective cohort study, level III.

Design: Patients who underwent knee ACI (Current Procedural Terminology [CPT] 27412) or OCA (CPT 27415) with minimum 2-year follow-up were queried from a national insurance database.

Double Tension Slide Technique as a Novel Repair for Distal Biceps Tendon Tear: A Biomechanical Evaluation.

Background A comparative biomechanical analysis of two distal biceps tendon repair techniques was performed: a single suture tension slide technique (TST) and two suture double tension slide (DTS) technique. Methodology Ten matched pairs of fresh frozen human cadaveric elbows (20 elbows) were randomly separated into two cohorts for distal biceps tendon repair. One cohort underwent the TST, and the other underwent the DTS technique.

Worse Preoperative Pain and Higher Activity Levels Predict Patient Choice of Formal Physical Therapy After Primary Anterior Total Hip Arthroplasty.

Background: The purpose of this randomized controlled trial is (1) to compare the efficacy of supervised formal physical therapy (PT) and self-directed home exercises and (2) to identify independent predictors of transitioning from self-directed home exercises to supervised formal PT following total hip arthroplasty (THA) via an anterior approach.

Methods: After Institutional Review Board approval, 147 patients undergoing primary unilateral THA through anterior approach were enrolled and randomized to receive either clinic or home-based PT. Surveys with Hip Disability Osteoarthritis Outcome Scores (HOOS) and Short Form-12 Health Survey scores for both groups were obtained before surgery and at 6, 14, and 24 weeks after surgery.

Find your coat: Using correlative light and electron microscopy to study intracellular protein coats.

Protein coats, important for vesicular trafficking in eukaryotic cells, help shape membranes and package cargo. But their dynamic construction cannot be fully understood until the distinct steps of their assembly in their native intracellular context at molecular resolution can be visualized. For this, correlative light and electron microscopy (CLEM) is an essential tool.

Mandatory Nicotine Cessation for Elective Orthopedic Hip Procedures Results in Reduction in Postoperative Nicotine Use.

Purpose To determine the efficacy of mandatory preoperative nicotine cessation on postoperative nicotine use, and to identify independent predictors of nicotine use relapse in subjects undergoing hip preservation surgery or total hip arthroplasty by a single fellowship-trained orthopedic surgeon. Methods Consecutive subjects that underwent hip surgery from November 2014 to December 2017 were reviewed. Subjects who self-reported nicotine use, quit prior to surgery, and completed a minimum one-year follow-up were included.

Platelet-Rich Plasma Augmentation for Isolated Arthroscopic Meniscal Repairs Leads to Significantly Lower Failure Rates: A Systematic Review of Comparative Studies.

Background: Studies have reported relatively high failure rates of isolated meniscal repairs. Platelet-rich plasma (PRP) has been suggested as a way to increase growth factors that enhance healing.

Purpose: To compare (1) meniscal repair failures and (2) patient-reported outcomes after isolated arthroscopic meniscal repair augmented with and without PRP.

Superior Capsular Reconstruction: A Systematic Review of Surgical Techniques and Clinical Outcomes.

Purpose: To evaluate surgical techniques and clinical outcomes of arthroscopic superior capsular reconstruction (SCR) for the treatment of massive irreparable rotator cuff tears.

Methods: A systematic review was registered with PROSPERO and performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. The PubMed, Scopus, and Cochrane databases were searched.