bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel hepatocyte SHP/CCL2 axis controls liver inflammation in NAFL to NASH transition
Authors: Magee Nancy S. , Zou An , Delker Don , Zhang Yuxia 
Published: November 2023

ObjectiveNonalcoholic fatty liver disease (NAFLD) is a burgeoning health problem worldwide, ranging from simple steatosis or non‐alcoholic fatty liver (NAFL) to a more aggressive non‐alcoholic steatohepatitis (NASH) with an increased mortality. Understanding what drives the transition from NAFL to NASH is essential to develop effective prophylactic and therapeutic strategies for NASH. Small heterodimer partner (SHP, Nr0b2) is a unique nuclear receptor important for bile acid, lipid, and glucose metabolism. The aim for this study is to explore a novel mechanism by which hepatocyte SHP regulates liver inflammation during NAFL transition to NASH.MethodsHuman liver samples from patients with simple steatosis or NASH were used to examine SHP expression. To produce a mouse model of NASH, a diet high in fat, cholesterol, and fructose (HFCF) was given to 2 month‐old male mice. Hepatocyte‐specific overexpression of SHP was achieved by tail vein injection with adeno‐associated virus 8 (AAV8) expressing SHP, driven by the alpha‐1‐antitrypsin (AAT) promoter (AAV8‐AAT‐SHP). On the other hand, hepatocyte‐specific SHP‐deficiency was induced by the administration of AAV8 expressing Cre recombinase driven by the thyroxine‐binding globulin (Tbg) promoter (AAV8‐Tbg‐Cre) on the 2 month‐old male Shpflox/flox mice. The extent of steatosis, inflammation, and fibrosis were evaluated in liver tissues. Mouse primary hepatocytes and macrophage‐like RAW 264.7 cells were included to study mechanisms.ResultsSHP was decreased in human patients with NASH and in the dietary‐induced mouse model of NASH, suggesting a biological relevance of SHP function in NASH pathogenesis. Increasing hepatic SHP level via AAV8 mediated gene delivery ameliorated diet‐induced NASH progression. In contrast, hepatocyte‐specific deletion of Shp in adult mice (Shp‐HKO) resulted in infiltration of macrophages and CD4+ T cells into the liver, which was further supported by the activation of inflammatory signaling pathways in Shp‐HKO as shown by RNA sequencing. As a result, hepatocyte‐specific Shp‐deficiency sensitized the liver to diet‐induced inflammation and fibrosis with an attenuation of steatosis. As a proof of concept, in vitro deletion of SHP in mouse primary hepatocytes increased the secretion of chemokine (C‐C motif) ligand 2 (CCL2). Most importantly, the conditioned medium from Shp‐deficient hepatocytes induced a pro‐inflammatory M1 polarization in RAW264.7 cells and promoted RAW264.7 cell migration. On a molecular level, SHP inhibited CCL2 expression through a direct inhibition of NFκB p65‐induced CCL2 transcription.ConclusionsOur study uncovers a novel mechanism by which nuclear receptor SHP regulates hepatocyte and macrophage communication in the NAFL transition to NASH, which is mediated through inhibiting NFκB/CCL2 axis‐initiated macrophage activation.Support or Funding InformationGrant support: NCI K22CA184146 and NIH P20 GM103549 to Yuxia Zhang.
Pro‐Inflammatory Monocyte Derived Macrophages Accumulate in Uninjured Aged Murine Livers
Authors: Stahl Elizabeth C , Brown Bryan N 
Published: November 2023

In the United States, 30 million individuals suffer from chronic liver diseases, which present with increased severity and poor prognosis in the elderly population, in part due to dysfunction of the aged immune system. Immunosenescence describes the dysregulation of immune cell function with aging, which preferentially effects tissue‐resident macrophages compared to bone marrow derived macrophages. Recent findings suggest that liver macrophages can be divided into two F4/80+ subsets: CD68+ embryonically‐derived Kupffer cells and CD11b+ bone marrow derived cells, which exhibit specific cell functions. It is currently unclear how the macrophage populations residing in the liver are phenotypically and functionally impacted by aging, which may have implications for the onset and progression of inflammatory disease and liver pathology in elderly populations.The aim of this study is to characterize the liver macrophage compartment from young (8–10 week) and aged (18–20 month) C57BL/6 wild‐type mice using immunohistochemistry and flow cytometry. First, we identified a significant increase in the total number of macrophages residing in aged livers. Preliminary in vitro studies showed that aged macrophages were primed towards a higher phagocytic capacity, regardless of M1 (LPS + IFN‐gamma) or M2 (IL‐4) stimuli, suggesting an inherent level of pro‐inflammatory activation with aging. In addition, the aged macrophage population contained a greater proportion of CD11b+ cells, suggesting an increase in bone marrow‐derived macrophages residing in the liver. To confirm this, we examined the liver macrophage profile of aged CCR2 knock‐out mice, which lack the receptor for monocyte chemoattractant protein‐1 (MCP‐1), an important signaling molecule for monocyte recruitment following injury. Interestingly, we found that mice deficient in CCR2 had a reversal in liver macrophage profile, from CD11b+ predominant to CD68+ predominant cell subsets, demonstrating that monocyte derived macrophages accumulate in the uninjured aged liver at least in part due to MCP‐1. Future studies will further characterize the functions of the CD11b and CD68 liver‐macrophages with aging, which will aid in the understanding of liver pathology onset and progression in elderly individuals.Support or Funding Information1. This work was partially supported by an NIH‐NIBIB training grant (T32‐EB001026) entitled “Cellular Approaches to Tissue Engineering and Regeneration” and a Pilot & Feasibility grant from the Pittsburgh Liver Research Center.
An Anatomical Basis for Cortical Crossmodal Plasticity
Authors: Meredith M. Alex , Lomber Stephen G. 
Published: November 2023

When a major sensory system is lost, the remaining sensorymodalities functionally reorganize the vacated neural territories through a process termed “crossmodal plasticity.” The mechanisms underlying this effect have been assumed to involve the in growth of projections from novel sources, and/or the unmasking of existing but ‘silent’ connections. However, our recent experiments indicate that the anatomical basis for crossmodal plasticity after early‐deafness actually is a more complex process involving a pervasive maintenance of connections, laminar‐ and neuron‐dependent synaptic changes related toaxonal pruning/sprouting and cartographic changes that occur in a region‐specific basis.Support or Funding InformationSupported by the National Institutes of Health Grant (NS‐39460; MAM), the Virginia Commonwealth University Presidential Research Initiatives Program (MAM) and the Canadian Institutes of Health Research (SGL).
Constitutive Cardiomyocyte Proliferation in the Postnatal Leopard Gecko (Eublepharis macularius)
Authors: Jacyniak Kathy , Vickaryous Matthew Kenneth 
Published: November 2023

Although historically considered to be mitotically inactive, mammalian cardiac muscle cells (cardiomyocytes) are now widely viewed as being capable of at least low levels of homeostatic renewal throughout adulthood. Emerging evidence indicates that the extent to which cardiomyocytes can spontaneously re‐enter the cell cycle correlates with the capacity for cardiac self‐repair and regeneration. Therefore, proliferation rates may offer a predictive tool for investigating the regenerative potential of a species. Here we explore homeostatic cardiomyocyte proliferation in a representative reptile, the leopard gecko (Eublepharis macularius). The gecko heart is characterized by a trabeculated, spongy‐like ventricular lumen. This architecture is also seen in species capable of cardiac regeneration (such as zebrafish), as it provides an increased surface area for diffusion with a decreased reliance on coronary circulation. To assess cardiac cell proliferation, we employed a short duration bromodeoxyurdine (BrdU) pulse‐chase experiment (2 day pulse, 7 day chase), and immunostained for the S phase marker proliferating cell nuclear antigen (PCNA) and the mitotic marker phosphorylated histone H3 (pHH3). We determined that cardiac cells of the gecko heart continually proliferate, even into adulthood. Using double immunofluorescence, we then co‐localized the cardiomyocyte marker myosin heavy chain (MHC) with each of PCNA and pHH3. We found that ~10% of cardiomyocytes have entered the synthesis phase (MHC+/PCNA+), while ~0.5% are mitotically active (MHC+/pHH3+). Next, we performed a long duration BrdU pulse‐chase experiment (7 day pulse, 140 day chase). Unexpectedly, we observed long‐term label‐retaining (= slow cycling) cells throughout the ventricular myocardium. These data suggest that the gecko heart contains populations of both constitutively active and comparatively quiescent cells. Our results combined with a trabeculated ventricular architecture point towards the gecko as an excellent candidate to study cardiac self‐repair and regeneration.Support or Funding InformationNatural Sciences and Engineering Research Council (NSERC) Discovery Grant 400358
Free‐body analysis of the masticatory muscles in a caviomorph rodent, Cavia porcellus
Authors: Druzinsky Robert E. , Ulm Ashley , Vinyard Christopher J. , Iriarte‐Diaz Jose 
Published: November 2023

Guinea pigs (Cavia porcellus) and other caviomorph rodents are hystricognaths. In hystricognaths, there is a groove for the pars reflexa of the superficial masseter in the ventral border of the mandible (Druzinsky, 2007). In the guinea pig (Cavia) the tendon of the pars reflexa has a dense connective tissue sesamoid that permits the tendon to glide through the groove. These South American hystricognaths are also hystricomorphs. The zygomatico‐mandibularis muscle originates on the snout and converges on a tendon that runs posteriorly through the infraorbital foramen. The tendon runs over the bony root of the zygomatic arch and turns inferiorly, to insert at the anterior end of the masseteric groove. A second sesamoid is found in this tendon, which allows the tendon to glide over the root of the zygomatic arch. Each of these elaborations of the masticatory muscles is a pinnate muscle that curves around a bony structure, acting as a pulley, and permitting the muscle to be longer than similar muscles in other mammals.To analyze the mechanics of the caviomorph masticatory apparatus we are creating a 3D model of the skull, jaw, and masticatory muscles through contrast enhanced micro‐CT. The head of an adult guinea pig was soaked in a solution of called iodine potassium iodide (I2KI) for several weeks and then scanned at Northeast Ohio College of Medicine using the Scanco vivaCT micro‐CT. The Materialize Mimics® Innovation Suite will be used to segment the bones, teeth, and muscles to capture the detailed morphology.Preliminary results of a free body analysis (see Reed, Iriarte‐Diaz, and Diekwisch, 2016 for methods) suggests that the pulley mechanisms of the masseter complex permit these muscles to be long, which allows them to have long excursions and produce significant forces at large gapes.
Sonic hedgehog (Shh) in parotid saliva is a cell signaling moiety that acts as stem cells in taste buds to maintain normal taste function
Authors: Henkin Robert I , Abdelmeguid Mona 
Published: November 2023

Taste bud growth and development in animals has been inhibited by the absence of Shh with destruction of taste bud architecture. Replacement of Shh reverses this effect and restores normal taste bud architecture and taste function. Vismodegib, a drug used to treat basal cell carcinoma, caused diminution of Shh secretion and caused taste loss in these patients. Drugs which inhibited Shh secretion in animals also caused taste loss. Because of our interest in taste function these results led us to hypothesize that Shh, a known cell signaling moiety, would be present in parotid saliva, the biological fluid which supports taste bud growth and development, and that its decreased secretion would be associated with taste loss (hypogeusia). To test this hypothesis we evaluated if Shh were present in parotid saliva in 27 normal subjects and in 81 patients with hypogeusia related to several etiologies. Results demonstrated that Shh was present in parotid saliva of normal subjects and that Shh levels in patients with hypogeusia of all etiologies were significantly lower than in normal subjects. These results are consistent with Shh acting as a taste bud growth factor consistent with our previous results in which specific salivary moieties act on stem cells in taste buds to develop growth and perpetuation of taste bud receptors. Without salivary Shh, taste bud receptor development in humans is inhibited, as it is in animals. Without salivary Shh, taste buds exhibit apoptosis which destroys taste bud architecture similar to results in animals. This is the first demonstration of Shh in human saliva and is consistent with this signaling moiety acting as a taste bud growth factor which maintains normal taste function by stem cell receptor activation with subsequent growth and development of taste bud receptors.Support or Funding InformationThere is no source of funding to declare.
Why mammalian cells respire?
Authors: Chandel Navdeep S. 
Published: November 2023

For decades, the two major functions linked to the mitochondrial respiratory chain has been to replenish NAD or FAD thus allowing the TCA (Krebs) cycle to generate metabolites for the production of macromolecules and to generate a proton motive force for ATP production. We have elucidated that the mitochondrial respiratory chain has a third distinct role whereby it participates in cellular signaling pathways through the release of reactive oxygen species (ROS). Our work has implicated the necessity of mitochondrial ROS for multiple biological processes including hypoxic activation of HIFs, cellular differentiation, and T cell activation. Previously, the dogma in the field had been that mitochondrial ROS are only produced in pathological settings to cause both cellular and DNA damage. However, we have demonstrated that mitochondrial ROS are utilized as messengers to maintain normal biological and physiological functions. More recently, our work has shown how mitochondrial metabolites influence the epigenome. I will present our ongoing work on the mitochondria beyond their role in energy production to function as signaling organelles.Support or Funding InformationThis work is supported by AG04966, HL071643, and CA197532.
Mitochondrial pathway of apoptosis
Authors: Wang Xiaodong 
Published: November 2023

Our studies of programmed cell death in the last twenty years have taken into three interwoven directions. The first is to identify the molecular components and biochemical reactions of cell death programs; Secondly, to understand the physiological and pathological significance of programmed cell death; and finally, to derive therapeutic strategies based on the knowledge of programmed cell death to treat human diseases like cancer, autoimmune diseases, and degenerative diseases.One of the most surprising findings of these studies is the role of mitochondria, the classical viewed powerhouse and metabolic center of eukaryotic cells, in programmed cell death in mammalian cells. Our laboratory discovered that cytochrome c, once released from the mitochondria, is able to serve as a protein ligand to trigger the activation of an apical apoptotic caspase, caspase‐9, through the formation of apoptosome. We also discovered a second mitochondrial protein Smac that neutralizes caspase inhibition imposed by the inhibitor of apoptotic proteins, IAPs, when comes to the cytosol during apoptosis. We collaborated with Yigong Shi's group to identify the N‐terminal four amino acid residues as the functional motif of Smac; and with Patrick Harran and Jef De Brabander to make a small molecule mimetic of Smac protein. The Smac mimetics not only are used as valuable research tools but different variants of the molecule are in human clinical trials for cancer.The Smac mimetic led us to the finding that in some cell types, a caspase‐independent form of programmed cell death occurs in the presence of Smac mimetic plus caspase inhibitors in response to tumor necrosis factor family of cytokines or toll‐like receptor ligands. We subsequently worked out the core biochemical program for this form of cell death, also called necroptosis. The key signaling molecule of necroptosis is receptor interacting kinase 3, RIP3, which is activated upon induced interaction with a related kinase RIP1 or an adaptor protein TRIF, upon activation of TNF family of receptors or TLR3/4, respectively. RIP3 then phosphorylates and activates its substrate, a peudokinase MLKL, resulting in its oligomerization and translocation from the cytosol to intracellular and plasma membranes. Once on the membrane, MLKL, binds to negatively charged phospholipids and cause membrane disruption, leading to necrotic cell death. Using mouse model of RIP3 knockout and antibodies specifically recognizing the phosphorylated MLKL, necroptosis has been shown to be important for defending microbial infection and participating in tissue damage response. More recently, the data from our laboratory as well as others have shown that necroptosis is part of etiology of in several forms of degenerative disease models and aging.In this up coming meeting, I will discuss the up‐to‐date progress from my laboratory on the molecular pathways of different forms of programmed cell death, small molecules modulating them, and potential therapeutic usages of these compounds.
Deciphering the ZIP Codes of a Cell
Authors: Dahms Nancy M. 
Published: November 2023

Lysosomes are acidified organelles capable of degrading a heterogeneous population of proteins, lipids, and glycans that are obtained from autophagic, endocytic, and phagocytic pathways. The activity of lysosomes depends upon a collection of over 60 soluble acid hydrolases that must be continually delivered to lysosomes from their site of synthesis in the endoplasmic reticulum. The acid hydrolases' N‐glycans undergo unique posttranslational modifications by two enzymes in the Golgi that results in the acquisition of phosphorylated mannose, either as a phosphomonoester (mannose 6‐phosphate, M6P) or a phosphodiester (M6P‐GlcNAc), and marks them for delivery to lysosomes by specific receptors, M6P receptors (MPRs). Failure to tag acid hydrolases with M6P results in developmental defects and the lysosomal storage diseases, mucolipidosis II and III. The phosphorylated N‐glycans are diverse in structure due to differences in their size, number of phosphorylated mannose residues (one or two), presence of M6P and/or M6P‐GlcNAc, and the location of the phosphomannosyl residues on the different branches of the N‐glycan. A subset of this diverse array of phosphorylated N‐glycans are recognized by two distinct MPRs, the ~46kDa cation‐dependent MPR (CD‐MPR) and the ~300kDa cation‐independent MPR (CI‐MPR), that carry acid hydrolases from the TGN to endosomal compartments where the acidic environment causes the MPRs to release their cargo. Additionally, cell surface internalization of exogenously supplied ligands, as occurs in enzyme replacement therapy for the treatment of lysosomal storage diseases, is dependent upon receptor‐mediated endocytosis carried out by the CI‐MPR. To determine how the MPRs carry their diverse cargo, glycan microarrays, solid phase binding assays using acid hydrolases, mutagenesis studies and structural biology of the MPRs are used to identify structural elements essential for the trafficking of acid hydrolases to lysosomes.Support or Funding InformationNIH R01DK042267
Glycan‐Binding Proteins as Microbial Detectors
Authors: Kiessling Laura L. 
Published: November 2023

Humans and other mammals live with microbial residents. A host must therefore distinguish between microorganisms that are benign (commensal), beneficial (mutualist/symbiont), or pathogenic. The mechanisms involved in surveillance of bacteria, fungi, viruses, and parasites have not been fully delineated, but lectins are emerging as important components. Indeed, the glycans displayed on mammalian cell surfaces can differ markedly from those on microbes. Microbial cell‐surface glycans therefore serve as a rich identification code that can be read by host lectins to make decisions about which microbes stay and which must go. To this end, we have examined the recognition properties of the intelectins, which are X‐type lectins that reside at mucosal barriers. This seminar will describe our recent results on intelectin recognition and on the properties of lectins that allow them to function as microbial detectors. We envision that an understanding of mucosal lectin recognition can lead to new strategies to combat pathogens and new approaches to regulate microbiome composition to promote human health.Support or Funding InformationWe thank the NIH (R01GM55984 and R01AI063596) for support.
Regulation of manganese homeostasis and detoxification by the efflux transporter SLC30A10
Authors: Mukhopadhyay Somshuvra 
Published: November 2023

Homozygous loss‐of‐function mutations in SLC30A10 induce familial manganese‐induced parkinsonism. We previously demonstrated that the wild‐type SLC30A10 protein functions as a cell surface‐localized manganese efflux transporter that transports manganese from the cytosol to the cell exterior, reduces intracellular manganese levels and protects against manganese‐induced neurotoxicity. In contrast, disease‐causing mutations block the intracellular trafficking and manganese efflux function of SLC30A10. I will summarize the above published findings and then present three short stories from projects that we are currently pursuing. The first project is a structure‐function study that aims to determine the mechanism of manganese transport via SLC30A10; current data suggest that the mechanism of ion coordination in SLC30A10 may be fundamentally different from related transporters in its superfamily. The second project is designed to understand the mechanism by which manganese regulates SLC30A10 activity; our studies show that increased intracellular manganese enhances SLC30A10 transcription in a metal response element‐independent manner. Finally, the third project is a mouse study that focuses on elucidating the mechanisms by which loss of SLC30A10 function at the cellular level leads to the onset of parkinsonism; for this project, I will present phenotypic characterization of full‐body and organ‐specific SLC30A10 knock‐out mice that we generated.Support or Funding InformationSupported by NIH/NIEHS grants R00‐ES020844 and R01‐ES024812 (S.M.)