During development, inflammation or tissue injury, macrophages may successively engulf and process multiple apoptotic corpses via efferocytosis to achieve tissue homeostasis. How macrophages may rapidly adapt their transcription to achieve continuous corpse uptake is incompletely understood. Transcriptional pause/release is an evolutionarily conserved mechanism, in which RNA polymerase (Pol) II initiates transcription for 20-60 nucleotides, is paused for minutes to hours and is then released to make full-length mRNA.
View Article and Find Full Text PDFAm J Physiol Cell Physiol
February 2024
Cellular reprogramming is characterized by the induced dedifferentiation of mature cells into a more plastic and potent state. This process can occur through artificial reprogramming manipulations in the laboratory such as nuclear reprogramming and induced pluripotent stem cell (iPSC) generation, and endogenously in vivo during amphibian limb regeneration. In amphibians such as the Mexican axolotl, a regeneration permissive environment is formed by nerve-dependent signaling in the wounded limb tissue.
View Article and Find Full Text PDFLittle is known about how the newly regenerated limb tissues in the Mexican axolotl seamlessly integrate with the remaining stump tissues to form a functional structure, and why this doesn't occur in some regenerative scenarios. In this study, we evaluate the phenomenological and transcriptional characteristics associated with integration failure in ectopic limb structures generated by treating anterior-located ectopic blastemas with Retinoic Acid (RA) and focusing on the "bulbus mass" tissue that forms between the ectopic limb and the host site. We additionally test the hypothesis that the posterior portion of the limb base contains anterior positional identities.
View Article and Find Full Text PDFThe retina is highly metabolically active, relying on glucose uptake and aerobic glycolysis. Situated in close contact to photoreceptors, a key function of cells in the retinal pigment epithelium (RPE) is phagocytosis of damaged photoreceptor outer segments (POS). Here we identify RPE as a local source of insulin in the eye that is stimulated by POS phagocytosis.
View Article and Find Full Text PDFSynthetic gene circuits that precisely control human cell function could expand the capabilities of gene- and cell-based therapies. However, platforms for developing circuits in primary human cells that drive robust functional changes in vivo and have compositions suitable for clinical use are lacking. Here, we developed synthetic zinc finger transcription regulators (synZiFTRs), which are compact and based largely on human-derived proteins.
View Article and Find Full Text PDFWhen the Accessory Limb Model (ALM) regenerative assay was first published by Endo, Bryant, and Gardiner in 2004, it provided a robust system for testing the cellular and molecular contributions during each of the basic steps of regeneration: the formation of the wound epithelium, neural induction of the apical epithelial cap, and the formation of a positional disparity between blastema cells. The basic ALM procedure was developed in the axolotl and involves deviating a limb nerve into a lateral wound and grafting skin from the opposing side of the limb axis into the site of injury. In this chapter, we will review the studies that lead to the conception of the ALM, as well as the studies that have followed the development of this assay.
View Article and Find Full Text PDFEpithelial tissues such as lung and skin are exposed to the environment and therefore particularly vulnerable to damage during injury or infection. Rapid repair is therefore essential to restore function and organ homeostasis. Dysregulated epithelial tissue repair occurs in several human disease states, yet how individual cell types communicate and interact to coordinate tissue regeneration is incompletely understood.
View Article and Find Full Text PDFApoptosis of cells and their subsequent removal through efferocytosis occurs in nearly all tissues during development, homeostasis, and disease. However, it has been difficult to track cell death and subsequent corpse removal in vivo. We developed a genetically encoded fluorescent reporter, CharON (Caspase and pH Activated Reporter, Fluorescence ON), that could track emerging apoptotic cells and their efferocytic clearance by phagocytes.
View Article and Find Full Text PDFNeurodevelopment and efferocytosis have fascinated scientists for decades. How an organism builds a nervous system that is precisely tuned for efficient behaviors and survival and how it simultaneously manages constant somatic cell turnover are complex questions that have resulted in distinct fields of study. Although neurodevelopment requires the overproduction of cells that are subsequently pruned back, very few studies marry these fields to elucidate the cellular and molecular mechanisms that drive nervous system development through the lens of cell clearance.
View Article and Find Full Text PDFAnti-androgens are a common therapy in prostate cancer (PCa) targeting androgen receptor (AR) signaling. However, these therapies fail due to selection of highly aggressive AR-negative cancer cells that have no therapeutic options available. We demonstrate that elevating endogenous ceramide levels with administration of exogenous ceramide nanoliposomes (CNLs) was efficacious in AR-negative cell lines with limited efficacy in AR-positive cells.
View Article and Find Full Text PDFTherapies for head and neck squamous cell carcinoma (HNSCC) are, at best, moderately effective, underscoring the need for new therapeutic strategies. Ceramide treatment leads to cell death as a consequence of mitochondrial damage by generating oxidative stress and causing mitochondrial permeability. However, HNSCC cells are able to resist cell death through mitochondria repair via mitophagy.
View Article and Find Full Text PDFAlthough telepsychiatry has emerged as an innovative tool for increasing access to behavioral health services, few studies have examined the complexities associated with designing and implementing telepsychiatry programs. This column examines a multisite, multimodal telepsychiatry program that has been providing direct care, synchronous consultation, and asynchronous consultation services in rural Illinois since 2016. The program used quality improvement metrics and implementation science strategies to improve its long-term impact and sustainability.
View Article and Find Full Text PDFApoptotic cell clearance (efferocytosis) elicits an anti-inflammatory response by phagocytes, but the mechanisms that underlie this response are still being defined. Here, we uncover a chloride-sensing signalling pathway that controls both the phagocyte 'appetite' and its anti-inflammatory response. Efferocytosis transcriptionally altered the genes that encode the solute carrier (SLC) proteins SLC12A2 and SLC12A4.
View Article and Find Full Text PDFAminimides are key intermediates in the thermal cycloadditions of suitable alkenyl-hydrazine derivatives. Substrate modifications (β-,-dialkyl) allowed the isolation of these reactive intermediates, and the analysis of their stereochemistry provided support for concerted (Cope-type) hydroamination and concerted [3 + 2] aminocarbonylation reaction pathways. This work also establishes the applicability of these approaches to form complex aminimides in moderate to excellent yields.
View Article and Find Full Text PDFSome organisms, such as the Mexican axolotl, have the capacity to regenerate complicated biological structures throughout their lives. Which molecular pathways are sufficient to induce a complete endogenous regenerative response in injured tissue is an important question that remains unanswered. Using a gain-of-function regeneration assay, known as the Accessory Limb Model (ALM), we and others have begun to identify the molecular underpinnings of the three essential requirements for limb regeneration; wounding, neurotrophic signaling, and the induction of pattern from cells that retain positional memory.
View Article and Find Full Text PDFDevelopment and routine tissue homeostasis require a high turnover of apoptotic cells. These cells are removed by professional and non-professional phagocytes via efferocytosis. How a phagocyte maintains its homeostasis while coordinating corpse uptake, processing ingested materials and secreting anti-inflammatory mediators is incompletely understood.
View Article and Find Full Text PDFPhagocytes express multiple phosphatidylserine (PtdSer) receptors that recognize apoptotic cells. It is unknown whether these receptors are interchangeable or if they play unique roles during cell clearance. Loss of the PtdSer receptor Mertk is associated with apoptotic corpse accumulation in the testes and degeneration of photoreceptors in the eye.
View Article and Find Full Text PDFA phase separation/continuous flow strategy employing an oxidative Glaser-Hay coupling of alkynes has been applied toward the synthesis of the macrocyclic core of complex pharmaceutical vaniprevir. The phase separation/continuous flow strategy afforded similar yields at 100-500 times the concentration and at shorter reaction times than common slow addition/high dilution techniques. In addition, dendritic PEG cosolvents were employed in the phase separation strategy for the first time and shown to allow productive macrocyclization at concentrations up to 200 mM.
View Article and Find Full Text PDFA synthesis of neomarchantin A has been achieved wherein key bond constructions involving C-O or C-C bond formations were augmented via continuous flow techniques. Of note, the synthesis of neomarchantin A represents the first demonstration of catalytic macrocyclic olefin metathesis as a key step for the synthesis of a macrocyclic bisbibenzyl natural product.
View Article and Find Full Text PDFIntrinsic cell chirality has been implicated in the left-right (LR) asymmetry of embryonic development. Impaired cell chirality could lead to severe birth defects in laterality. Previously, we detected cell chirality with an micropatterning system.
View Article and Find Full Text PDFA 30-year-old, right-handed female presented 2 weeks postpartum with acute-onset severe headache, vertigo, and vomiting. Initial neurologic examination illustrated lingual dysarthria, horizontal nystagmus, right dysmetria on finger-to-nose testing, and weakness of the extremities. Magnetic resonance imaging showed a large, left lateral medullary infarction (Wallenberg syndrome) with cephalad extension into the ipsilateral pons as well as involvement of the left middle cerebellar peduncle.
View Article and Find Full Text PDFLeft-right (LR) asymmetry is a biologically conserved property in living organisms that can be observed in the asymmetrical arrangement of organs and tissues and in tissue morphogenesis, such as the directional looping of the gastrointestinal tract and heart. The expression of LR asymmetry in embryonic tissues can be appreciated in biased cell alignment. Previously an in vitro chirality assay was reported by patterning multiple cells on microscale defined geometries and quantified the cell phenotype-dependent LR asymmetry, or cell chirality.
View Article and Find Full Text PDFFollowing central nervous system (CNS) injury, activated astrocytes form glial scars, which inhibit axonal regeneration, leading to long-term functional deficits. Engineered nanoscale scaffolds guide cell growth and enhance regeneration within models of spinal cord injury. However, the effects of micro-/nanosize scaffolds on astrocyte function are not well characterized.
View Article and Find Full Text PDFBackground: Despite American Society of Clinical Oncology (ASCO) and National Comprehensive Cancer Network (NCCN) guidelines recommending that oncologists discuss advance care planning (ACP) with patients with stage IV cancer early in treatment, in standard practice ACP remains a late step of a terminal illness. ACP preserves comfort and dignity at the end of life, ensuring patients receive the care that they desire.
Methods And Materials: A feasibility study in patients with stage IV cancer was developed to test whether incorporating ACP immediately after a stage IV cancer diagnosis is feasible.