Multiple Insults Research Articles

Heterozygous loss of Engrailed-1 and α-synucleinopathy (En1/SYN): A dual-hit preclinical mouse model of Parkinson's disease, analyzed with artificial intelligence

In this study, we develop and validate a new Parkinson's disease (PD) mouse model that can be used to better understand how the disease progresses and to test the effects of new, potentially disease-modifying, PD therapies. Our central hypothesis is that mitochondrial dysfunction intercalates with misfolded α-synuclein (α-syn) accumulation in a vicious cycle, leading to the loss of nigral neurons. Our hypothesis builds on the concept that PD involves multiple molecular insults, including mitochondrial dysfunction and aberrant α-syn handling. We predicted that mitochondrial deficits, due to heterozygous loss of Engrailed-1 (En1+/−), combined with bilateral injections of pathogenic α-syn fibrils (PFFs), will act to generate a highly relevant PD model – the En1/SYN model. Here, En1+/− mice received bilateral intrastriatal stereotaxic injections of either PBS or α-syn fibrils and were analyzed using automated behavioral tests and deep learning-assisted histological analysis at 2, 4, and 6 months post-injection. We observed significant and progressive Lewy body-like inclusion pathology in the amygdala, motor cortex, and cingulate cortex, as well as the loss of tyrosine hydroxylase-positive (TH+) cells in the substantia nigra. The En1/SYN model also exhibited significant motor impairments at 6 months post-injection, which were however not exacerbated as we had expected. Still, this model has a comprehensive number of PD-like phenotypes and is therefore superior when compared to the α-syn PFF or En1+/− models alone.

Olive Oil's Attenuating Effects on Lipotoxicity.

Dietary fatty acids play a role in the pathogenesis of obesity-associated nonalcoholic fatty liver disease. Lipotoxicity in obesity mediates insulin resistance, endothelial dysfunction, atherosclerosis, and gut microbiota dysbiosis. Cardiovascular complications are the main cause of morbidity and mortality in obese, insulin-resistant, and type 2 diabetes mellitus patients.Interventions targeting lipotoxicity are the main issue in preventing its multiple insults. Lifestyle modifications including healthy eating and regular exercise are the primary recommendations. Treatments also include drugs targeting energy intake, energy disposal, lipotoxic liver injury, and the resulting inflammation, fibrogenesis, and cirrhosis.Diet and nutrition have been linked to insulin resistance, an increased risk of developing type 2 diabetes, and impaired postprandial lipid metabolism. Low-fat diets are associated with higher survival. The Mediterranean diet includes an abundance of olive oil. Extra-virgin olive oil is the main source of monounsaturated fatty acids in Mediterranean diets. An olive oil-rich diet decreases triglyceride accumulation in the liver, improves postprandial triglyceride levels, improves glucose and insulin secretions, and upregulates GLUT-2 expression in the liver. The exact molecular mechanisms of olive oil's effects are unknown, but decreasing NF-kB activation, decreasing LDL oxidation, and improving insulin resistance by reducing the production of inflammatory cytokines (TNF-α and IL-6) and upregulating kinases and JNK-mediated phosphorylation of IRS-1 are possible principal mechanisms. Olive oil phenolic compounds also modulate gut microbiota diversity, which also affects lipotoxicity.In this review, we document lipotoxicity in obesity manifestations and the beneficial health effects of the Mediterranean diet derived from monounsaturated fatty acids, mainly from olive oil.

TRPA1 channel mediates oxidative stress defense in cancer

The unscheduled proliferation of cancer cells outside their natural niches subjects the cells to multiple insults, such as metabolic aberrations, detachment from the extracellular matrix (ECM), hypoxia, and immune cell attacks. Oxidative stress is a hallmark of cancer because these insults can all lead to the accumulation of reactive oxygen species (ROS). However, it remained largely elusive how cancer cells are able to adapt to harsh oxidative environments. Here, we provide evidence that cancer cells co-opt the neuronal ROS-sensing channel TRPA1 to tolerate highly oxidative environments. While TRPA1 is usually expressed at sensory neurons, we found that the channel is also overexpressed in various types of human cancer. TRPA1 does not affect canonical ROS-neutralizing programs but senses ROS and upregulates Ca2＋-dependent anti-apoptotic programs that promotes oxidative-stress tolerance. These findings offer a significant advance in our understanding of adaptation mechanisms to oxidative stress, which represents a substantial hurdle that impedes tumor initiation and progression.

Mitochondrial dysfunction at the cornerstone of inflammatory exacerbation in aged macrophages.

Immunosenescence encompasses multiple age-related adaptations that result in increased susceptibility to infections, chronic inflammatory disorders, and higher mortality risk. Macrophages are key innate cells implicated in inflammatory responses and tissue homeostasis, functions progressively compromised by aging. This process coincides with declining mitochondrial physiology, whose integrity is required to sustain and orchestrate immune responses. Indeed, multiple insults observed in aged macrophages have been implied as drivers of mitochondrial dysfunction, but how this translates into impaired immune function remains sparsely explored. This review provides a perspective on recent studies elucidating the underlying mechanisms linking dysregulated mitochondria homeostasis to immune function in aged macrophages. Genomic stress alongside defective mitochondrial turnover accounted for the progressive accumulation of damaged mitochondria in aged macrophages, thus resulting in a higher susceptibility to excessive mitochondrial DNA (mtDNA) leakage and reactive oxygen species (ROS) production. Increased levels of these mitochondrial products following infection were demonstrated to contribute to exacerbated inflammatory responses mediated by overstimulation of NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome and cyclic GMP-ATP synthase (cGAS)-stimulator of interferon genes (STING) pathways. While these mechanisms are not fully elucidated, the present evidence provides a promising area to be explored and a renewed perspective of potential therapeutic targets for immunological dysfunction.

Biointerface mineralization generates ultraresistant gut microbes as oral biotherapeutics.

Despite the fact that oral microecologics are effective in modulating the gut microbiome, they always suffer from multiple insults during the journey from manufacture to arrival at the intestine. Inspired by the protective mechanism of mineralization, we describe a cytocompatible approach of biointerface mineralization that can generate an ultraresistant and self-removable coating on bacterial surface to solve these challenges. Mineral coating endows bacteria with robust resistances against manufacture-associated oxygen exposure, ultraviolet irradiation, and 75% ethanol. Following oral ingestion, the coating is able to actively neutralize gastric acid and release encapsulated bacteria through spontaneous yet rapid double-decomposition reaction. In addition to acid neutralization, the generated calcium ions can trigger micellar aggregation of bile acid, enabling dual exemptions from the insults of gastric acid and bile acid to achieve uncompromised bacterial viability. Further supported by the therapeutic efficacy of coated bacteria toward colitis mice, biointerface mineralization provides a versatile platform for developing next-generation living oral biotherapeutics.

Phosphoproteomics reveals rewiring of the insulin signaling network and multi-nodal defects in insulin resistance

The failure of metabolic tissues to appropriately respond to insulin (“insulin resistance”) is an early marker in the pathogenesis of type 2 diabetes. Protein phosphorylation is central to the adipocyte insulin response, but how adipocyte signaling networks are dysregulated upon insulin resistance is unknown. Here we employ phosphoproteomics to delineate insulin signal transduction in adipocyte cells and adipose tissue. Across a range of insults causing insulin resistance, we observe a marked rewiring of the insulin signaling network. This includes both attenuated insulin-responsive phosphorylation, and the emergence of phosphorylation uniquely insulin-regulated in insulin resistance. Identifying dysregulated phosphosites common to multiple insults reveals subnetworks containing non-canonical regulators of insulin action, such as MARK2/3, and causal drivers of insulin resistance. The presence of several bona fide GSK3 substrates among these phosphosites led us to establish a pipeline for identifying context-specific kinase substrates, revealing widespread dysregulation of GSK3 signaling. Pharmacological inhibition of GSK3 partially reverses insulin resistance in cells and tissue explants. These data highlight that insulin resistance is a multi-nodal signaling defect that includes dysregulated MARK2/3 and GSK3 activity.

Analysis of Monocyte Recruitment During Inflammation by Intravital Imaging.

Monocytes play essential roles in the inflammatory and anti-inflammatory processes that take place during an immune response, acting both within the vascular network and interstitially. Monocytes are activated, mobilized, and recruited in response to an inflammatory stimulus or different forms of tissue injury. The recruitment of circulating monocytes to the inflamed tissue is essential to resolving the injury.Monocyte recruitment is a multistep process that begins with a decrease in rolling velocity, is followed by adhesion to the endothelium and crawling over the luminal vessel surface, and culminates in monocyte transmigration into the surrounding tissue. Intravital microscopy is a powerful visualization tool for the study of leukocyte behavior and function, intercellular interactions, cell trafficking, and recruitment in pathological and physiological conditions. This modality is therefore widely used for the detailed analysis of the immune response to multiple insults and the molecular mechanisms underlying monocyte interactions within the vascular system in vivo. This chapter describes a protocol for the use of intravital microscopy to analyze monocyte recruitment from the blood vessel to the inflammatory site.

Structural Requirements for the Neuroprotective and Anti-Inflammatory Activities of the Flavanone Sterubin.

Alzheimer's disease (AD) is the most frequent age-associated disease with no treatments that can prevent, delay, slow, or stop its progression. Thus, new approaches to drug development are needed. One promising approach is the use of phenotypic screening assays that can identify compounds that have therapeutic efficacy in target pathways relevant to aging and cognition, as well as AD pathology. Using this approach, we identified the flavanone sterubin, from Yerba santa (Eriodictyon californicum), as a potential drug candidate for the treatment of AD. Sterubin is highly protective against multiple initiators of cell death that activate distinct death pathways, potently induces the antioxidant transcription factor Nrf2, and has strong anti-inflammatory activity. Moreover, in a short-term model of AD, it was able to prevent decreases in short- and long-term memory. In order to better understand which key chemical functional groups are essential to the beneficial effects of sterubin, we compared the activity of sterubin to that of seven closely related flavonoids in our phenotypic screening assays. Surprisingly, only sterubin showed both potent neuroprotective activity against multiple insults as well as strong anti-inflammatory activity against several distinct inducers of inflammation. These effects correlated directly with the ability of sterubin to strongly induce Nrf2 in both nerve and microglial cells. Together, these results define the structural requirements underlying the neuroprotective and anti-inflammatory effects of sterubin and they provide the basis for future studies on new compounds based on sterubin.

Conditioning Regimens are Associated with Distinct Patterns of Microbiota Injury in Allogeneic Hematopoietic Cell Transplantation.

The gut microbiota is subject to multiple insults in allogeneic hematopoietic cell transplantation (allo-HCT) recipients. We hypothesized that preparative conditioning regimens contribute to microbiota perturbation in allo-HCT. This was a retrospective study that evaluated the relationship between conditioning regimens exposure in 1,188 allo-HCT recipients and the gut microbiome. Stool samples collected from 20 days before transplantation up to 30 days after were profiled using 16S rRNA sequencing. Microbiota injury was quantified by changes in α-diversity. We identified distinct patterns of microbiota injury that varied by conditioning regimen. Diversity loss was graded into three levels of conditioning-associated microbiota injury (CMBI) in a multivariable model that included antibiotic exposures. High-intensity regimens, such as total body irradiation (TBI)-thiotepa-cyclophosphamide, were associated with the greatest injury (CMBI III). In contrast, the nonmyeloablative regimen fludarabine-cyclophosphamide with low-dose TBI (Flu/Cy/TBI200) had a low-grade injury (CMBI I). The risk of acute GVHD correlated with CMBI degree. Pretransplant microbial compositions were best preserved with Flu/Cy/TBI200, whereas other regimens were associated with loss of commensal bacteria and expansion of Enterococcus. Our findings support an interaction between conditioning at the regimen level and the extent of microbiota injury.

ACBP/DBI protein neutralization confers autophagy-dependent organ protection through inhibition of cell loss, inflammation, and fibrosis

Acyl-coenzyme A (CoA)-binding protein (ACBP), also known as diazepam-binding inhibitor (DBI), is an extracellular feedback regulator of autophagy. Here, we report that injection of a monoclonal antibody neutralizing ACBP/DBI (α-DBI) protects the murine liver against ischemia/reperfusion damage, intoxication by acetaminophen and concanavalin A, and nonalcoholic steatohepatitis caused by methionine/choline-deficient diet as well as against liver fibrosis induced by bile duct ligation or carbon tetrachloride. α-DBI downregulated proinflammatory and profibrotic genes and upregulated antioxidant defenses and fatty acid oxidation in the liver. The hepatoprotective effects of α-DBI were mimicked by the induction of ACBP/DBI-specific autoantibodies, an inducible Acbp/Dbi knockout or a constitutive Gabrg2F77I mutation that abolishes ACBP/DBI binding to the GABAA receptor. Liver-protective α-DBI effects were lost when autophagy was pharmacologically blocked or genetically inhibited by knockout of Atg4b. Of note, α-DBI also reduced myocardium infarction and lung fibrosis, supporting the contention that it mediates broad organ-protective effects against multiple insults.

Lithium Benzoate Exerts Neuroprotective Effect by Improving Mitochondrial Function, Attenuating Reactive Oxygen Species, and Protecting Cognition and Memory in an Animal Model of Alzheimer's Disease.

Background:Alzheimer’s disease (AD) is a multifactorial neurodegenerative disease affecting many cellular pathways, including protein aggregation, mitochondrial dysfunction, oxidative stress (OS), and neuroinflammation. Currently, no effective treatment for AD exists.Objective:We aim to determine the effect of lithium benzoate (LiBen) in protecting neurons from amyloid-β (Aβ) or other neurotoxin insults.Methods:Primary rat cortical neurons co-treated with neurotoxins and LiBen were used to examine its effect in cell viability, reactive oxygen species (ROS) clearance, and mitochondrial functions by MTT, CellRox fluorescence staining, and seahorse assay. Then, Barnes maze and prepulse inhibition test were performed in APP/PS1 mice that received chronic LiBen treatment to assess its effect on cognitive protection. Oral bioavailability of LiBen was also assessed by pharmacokinetic study in rat plasma.Results:In this study, we discovered that LiBen can attenuate cellular ROS level, improve mitochondrial function, increase cell viability against multiple different insults of mitochondrial dysfunction, Aβ accumulation, and neuroinflammation, and promote neurogenesis. We demonstrated that LiBen has advantages over lithium or sodium benzoate alone as LiBen displays superior neuroprotective efficacy and oral bioavailability than the other two agents when being applied either alone or in combination. Furthermore, chronic administration of LiBen showed protection for cognition as well as spatial memory and reduced the senile plaque deposition in brains of AD animal models.Conclusion:LiBen stands as a promising therapeutic agent for improving cognition and delaying the progression of AD.

Multifunctional Nanoassemblies for Cytotoxic Drug and Therapeutic Enzymes Delivery in Neuroblastoma Therapy

AbstractNeuroblastoma cells can acquire resistance mechanisms that make them invulnerable to chemotherapeutic agents. The use of nanoparticles as drug carriers provides the possibility to deliver several drugs simultaneously to specific tumoral cell populations, improving their therapeutic outcome. Herein, the development of a multifunctional nanoplatform based on the assembly of protocells (PC) and polymeric nanocapsules (PNC) is reported. PC provides the ability to transport and release cytotoxic drugs while PNC offers the capacity to transport enzymes to the tumoral tissues preserving their catalytic activity. Doxorubicin (Dox) and Glucose Oxidase (Gox) are housed within PC and PNC, respectively. The external surface of these nanoassemblies is decorated with synthetic targeting moieties, providing selectivity to neuroblastoma cells. Thus, the nanoplatform is endowed with the ability to generate multiple insults within neuroblastoma cells as cytotoxic drug release, glucose starvation, and oxidative damage. This nanoplatform exhibits significantly higher cytotoxic activity in comparison with only drug‐loaded protocells or empty protocells decorated with glucose oxidase nanocapsules, which points out the existence of a potent synergic effect between the action of both therapeutic agents: Dox and Gox. This strategy can be adapted to the production of multifunctional nanoassemblies, improving the arsenal against different types of tumors.

The heterogeneity of microglial activation and its epigenetic and non-coding RNA regulations in the immunopathogenesis of neurodegenerative diseases.

Microglia are resident immune cells in the brain and play a central role in the development and surveillance of the nervous system. Extensive gliosis is a common pathological feature of several neurodegenerative diseases, such as Alzheimer's disease (AD), the most common cause of dementia. Microglia can respond to multiple inflammatory insults and later transform into different phenotypes, such as pro- and anti-inflammatory phenotypes, thereby exerting different functions. In recent years, an increasing number of studies based on both traditional bulk sequencing and novel single-cell/nuclear sequencing and multi-omics analysis, have shown that microglial phenotypes are highly heterogeneous and dynamic, depending on the severity and stage of the disease as well as the particular inflammatory milieu. Thus, redirecting microglial activation to beneficial and neuroprotective phenotypes promises to halt the progression of neurodegenerative diseases. To this end, an increasing number of studies have focused on unraveling heterogeneous microglial phenotypes and their underlying molecular mechanisms, including those due to epigenetic and non-coding RNA modulations. In this review, we summarize the epigenetic mechanisms in the form of DNA and histone modifications, as well as the general non-coding RNA regulations that modulate microglial activation during immunopathogenesis of neurodegenerative diseases and discuss promising research approaches in the microglial era.

57. Staged vs same-day circumferential thoracolumbar spine surgery

<h3>BACKGROUND CONTEXT</h3> Complexity and potential risk to the patient in the perioperative period have led to circumferential spine fusion surgery often being performed in a staged fashion, whether in the same admission or split admission. There is no established protocol or clear evidence that this is beneficial to the patient. Previous studies of this topic have tended to favor same-day surgery to staged surgery with decreased blood loss, length of stay and cost. Multiple factors can potentially contribute to morbidity for these patients, including multiple insults activating inflammatory response and repeated exposures to anesthetics. <h3>PURPOSE</h3> To determine if there is a difference in complication profile between staged vs same-day circumferential, multi-approach thoracolumbar spine surgery. <h3>STUDY DESIGN/SETTING</h3> A retrospective single-center cohort assessment for adult patients undergoing multiple approach thoracolumbar fusion surgery from January 2012 to December 2021 in an academic center. <h3>PATIENT SAMPLE</h3> All patients who underwent anterior or lateral approaches for the purpose of disc preparation and fusion and subsequently had a posterior approach for screws were included. The same-day group had both parts performed under the same anesthetic vs the staged group who had separate anesthetics on separate days in a planned fashion <h3>OUTCOME MEASURES</h3> Primary outcome: complication rate at 90 days. Secondary outcomes: complication profile - readmission, reoperation, DVT/PE, Ileus, delayed extubation, infection. Surgical characteristics - length of stay, operative time, estimated blood loss, transfusion rates. Demographic characteristics -ages, sex, BMI, diabetes, smoking habits. <h3>METHODS</h3> A retrospective single-center cohort assessment for adult patients undergoing multiple approach thoracolumbar fusion surgery from January 2012 to December 2021. Patients who underwent anterior or lateral approaches for the purpose of disc preparation and fusion and subsequently had a posterior approach for screws were included. The same-day group had both parts performed under the same anesthetic vs the staged group who had separate anesthetics on separate days in a planned fashion. Statistical comparison of demographic data (ages, sex, BMI, diabetes, smoking habits), complication rates (readmission, reoperation, DVT/PE, Ileus, delayed extubation, infection) and surgical characteristics (operative time, length of stay, estimated blood loss, transfusion rates) was made between the two groups. <h3>RESULTS</h3> A total of 1039 patients (918 same-day vs 121 staged) underwent circumferential thoracolumbar spine surgery from 2012 to 2021. The groups differed slightly in demographics with the staged group being slightly older (56.7 yrs same-day vs 59.6 yrs staged, p < 0.05) and had a higher incidence of smoking (6.6% same-day vs 22.3% staged, p < 0.001). The average time between stages was 2.5 days (SD 2.15). The total operative time was significantly longer in the staged group (354 min same-day vs 523 min staged, p < 0.001). The overall complication rate was not significantly different between the two groups (22.0% same-day vs 29.8% staged, p=0.748). Analysis of specific complications demonstrated an increase in DVT/PE (1.4% same-day vs 11.6% staged, p < 0.001) and postoperative ileus (4.2% same-day vs 15.7% staged, p < 0.001) in the staged group. The length of hospital admission was longer in the staged group (4.6 days same-day vs 7.7 days staged, p < 0.0001). <h3>CONCLUSIONS</h3> Staging circumferential surgery did not demonstrate statistical increase in complications at 90 days. However, review of specific postoperative complications including DVT/PE and postoperative ileus demonstrated significant increase in the staged group compared to the same-day group. The staged patients had a significantly longer hospital stay and their total surgery time was significantly longer. These would ultimately contribute heavily to hospital costs. There were potential limitations in the comparison of the groups with the staged patients being older and more likely to smoke. The study group recommends considering if staging the surgery is required as it can lead to increase in DVT/PE and postoperative ileus with prolonged stay in hospital. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Loss of stromal cell Thy-1 plays a critical role in lipopolysaccharide induced chronic lung allograft dysfunction.

Long-term survival of lung transplants lags behind other solid organs due to early onset of a fibrotic form of chronic rejection known as chronic lung allograft dysfunction (CLAD). Preventing CLAD is difficult as multiple immunologic and physiologic insults contribute to its development. Targeting fibroblast activation, which is the final common pathway leading to CLAD, offers the opportunity to ameliorate fibrosis irrespective of the initiating insult. Thy-1 is a surface glycoprotein that controls fibroblast differentiation and activation. To study the role of Thy-1 in CLAD, we utilized the minor antigen mismatched C57BL/6 (B6wild-type) or B6Thy-1-/-→C57BL/10 (B10) model of murine orthotopic lung transplantation with postoperative bacterial infection modeled by intratracheal lipopolysaccharide (LPS) administration. The effects of LPS on Thy-1 expression, proliferation, and gene expression were assessed in fibroblasts in vitro and the therapeutic potential of Thy-1 replacement was assessed in vivo. More severe CLAD was evident in B6Thy-1-/- →B10 grafts compared to B6wild-type →B10 grafts. LPS further accentuated fibrosis in B6wild-type →B10 grafts with some, but limited, effects on B6Thy-1-/- →B10 grafts. LPS contributed to Thy-1 loss from Thy-1(+) fibroblasts in vitro due to a decrease in mRNA expression. In addition, LPS promoted proliferation and upregulation of multiple inflammatory pathways in Thy-1(-) fibroblasts by gene expression analysis. Most importantly, replacement of Thy-1 through exogenous administration ameliorated the fibrotic phenotype post-LPS mediated modeling of infection. Our findings suggest that the loss of Thy-1 on fibroblasts is a previously unrecognized cause of CLAD and its replacement may offer therapeutic applications for amelioration of this disease post-transplantation in the setting of infectious stress responses.

Clinical Application of Induced Hepatocyte-like Cells Produced from Mesenchymal Stromal Cells: A Literature Review.

Liver disease is a leading cause of mortality worldwide, resulting in 1.3 million deaths annually. The vast majority of liver disease is caused by metabolic disease (i.e., NASH) and alcohol-induced hepatitis, and to a lesser extent by acute and chronic viral infection. Furthermore, multiple insults to the liver is becoming common due to the prevalence of metabolic and alcohol-related liver diseases. Despite this rising prevalence of liver disease, there are few treatment options: there are treatments for viral hepatitis C and there is vaccination for hepatitis B. Aside from the management of metabolic syndrome, no direct liver therapy has shown clinical efficacy for metabolic liver disease, there is very little for acute alcohol-induced liver disease, and liver transplantation remains the only effective treatment for late-stage liver disease. Traditional pharmacologic interventions have failed to appreciably impact the pathophysiology of alcohol-related liver disease or end-stage liver disease. The difficulties associated with developing liver-specific therapies result from three factors that are common to late-stage liver disease arising from any cause: hepatocyte injury, inflammation, and aberrant tissue healing. Hepatocyte injury results in tissue damage with inflammation, which sensitizes the liver to additional hepatocyte injury and stimulates hepatic stellate cells and aberrant tissue healing responses. In the setting of chronic liver insults, there is progressive scarring, the loss of hepatocyte function, and hemodynamic dysregulation. Regenerative strategies using hepatocyte-like cells that are manufactured from mesenchymal stromal cells may be able to correct this pathophysiology through multiple mechanisms of action. Preclinical studies support their effectiveness and recent clinical studies suggest that cell replacement therapy can be safe and effective in patients with liver disease for whom there is no other option.

PROTECTION OF TELOMERES 1b Modulates Cellular ROS and Chromatin Structure in Arabidopsis thaliana

Reactive oxygen species (ROS) are natural by‐products of cellular respiration, essential for cell signaling. They are also a major threat to telomere stability and can trigger senescence. Emerging studies reveal a broad role for telomere‐associated factors in modulating the response to oxidative stress. PROTECTION OF TELOMERES 1 (POT1) is one of the most conserved telomeric proteins, critical for both chromosome‐end protection and replication. POT1 is a single‐copy gene in most species. However, the flowering plant Arabidopsis thaliana encodes two highly divergent POT1 paralogs, AtPOT1a and AtPOT1b. AtPOT1a is an essential telomerase‐associated processivity factor. In contrast, AtPOT1b is not required for telomere replication or end protection, and its overexpression cannot complement the loss of AtPOT1a. Here we explore the natural separation‐of‐function within Arabidopsis POT1 paralogs and uncover a novel role for AtPOT1b in redox homeostasis. AtPOT1b expression is highly regulated, and restricted to seeds, root tips, and gametophytes, organs whose development is controlled by endogenous ROS. Strikingly, ectopic over‐expression of AtPOT1b decreases natural ROS levels throughout the plant, while a null mutation results in high levels of cellular and genomic oxidation, telomere length changes under multiple environmental insults, decreased chromatin compaction, decreased DNA methylation and increased expression of stress‐response genes. Consequently, atpot1b mutants have reduced fitness and are hypersensitive to chemical and environmental stresses. Finally, in response to oxidative stress, AtPOT1b expression increases and the protein accumulates at telomeres, suggesting that AtPOT1b may play a direct role in mitigating telomere oxidation. We postulate that AtPOT1b functions in a molecular rheostat that both senses and regulates cellular oxidation, thereby promoting genome stability in tissues where higher ROS levels are required for development.

The diagnosis and management of Cushing's syndrome in pregnancy.

Endogenous Cushing's syndrome (CS) is rarely encountered during pregnancy. Clinical and biochemical changes in healthy pregnancy overlap with those seen in pregnancy complicated by CS; the diagnosis is therefore challenging and can be delayed. During normal gestation, adrenocorticotrophic hormone, corticotrophin‐releasing hormone, cortisol, and urinary free cortisol levels rise. Dexamethasone administration fails to fully suppress cortisol in pregnant women without CS. Localisation may be hindered by non‐suppressed adrenocorticotrophic hormone levels in a large proportion of those with adrenal CS; smaller corticotroph adenomas may go undetected as a result of a lack of contrast administration or the presence of pituitary hyperplasia; and inferior petrosal sinus sampling is not recommended given the risk of radiation and thrombosis. Yet, diagnosis is essential; active disease is associated with multiple insults to both maternal and foetal health, and those cured may normalise the risk of maternal–foetal complications. The published literature consists mostly of case reports or small case series affected by publication bias, heterogeneous definitions of maternal or foetal outcomes or lack of detail on severity of hypercortisolism. Consequently, conclusive recommendations, or a standardised management approach for all, cannot be made. Management is highly individualised: the decision for surgery, medical control of hypercortisolism or adoption of a conservative approach is dependent on the timing of diagnosis (respective to stage of gestation), the ability to localise the tumour, severity of CS, pre‐existing maternal comorbidity, and, ultimately, patient choice. Close communication is a necessity with the patient placed at the centre of all decisions, with risks, benefits, and uncertainties around any investigation and management carefully discussed. Care should be delivered by an experienced, multidisciplinary team, with the resources and expertise available to manage such a rare and challenging condition during pregnancy.

The potential role of FNDC5/irisin in various liver diseases: awakening the sleeping beauties.

Fibronectin type III domain-containing protein 5 (FNDC5) is a transmembrane protein and the precursor of irisin, which serves as a systemic exerkine/myokine with multiple origins. Since its discovery in 2012, this hormone-like polypeptide has rapidly evolved to a component significantly involved in a gamut of metabolic dysregulations and various liver diseases. After a decade of extensive investigation on FNDC5/irisin, we are still surrounded by lots of open questions regarding its diagnostic and therapeutic values. In this review, we first concentrated on the structure-function relationship of FNDC5/irisin. Next, we comprehensively summarised the current knowledge and research findings regarding pathogenic roles/therapeutic applications of FNDC5/irisin in the context of non-alcoholic fatty liver disease, fibrosis, liver injury due to multiple detrimental insults, hepatic malignancy and intrahepatic cholestasis of pregnancy. Moreover, the prominent molecules involved in the underlying mechanisms and signalling pathways were highlighted. As a result, emerging evidence reveals FNDC5/irisin may act as a proxy for diagnosing liver disease pathology, a sensitive biomarker for assessing damage severity, a predisposing factor for surveilling illness progression and a treatment option with protective/preventive impact, all of which are highly dependent on disease grading and contextually pathological features.

Liver transplant biopsy interpretation: Diagnostic considerations and conundrums.

Liver transplantation is now a well-established therapeutic strategy for irreversible acute and chronic liver diseases. There is a broad spectrum of complications encountered in early and late period after transplantation and these contribute to significant morbidity and mortality. Distinguishing among these complications often requires interpretation of allograft biopsies. Histology is the gold standard for the diagnosis of rejection. However, interpretation of these biopsies is quite challenging due to the atypical and complex histomorphology. Multiple simultaneous insults, effects of immunosuppression (IMS), de novo complications, and presentations distinct from non-transplant setting are a few cardinal concerns. Awareness of the time period of occurrence of various complications, the most characteristic histological features or patterns, and distinguishing features between various complications are crucial. The management can be completely divergent; hence, recognition of dominant problem and interpretation in appropriate clinical context is much needed. This review focuses on histopathology of major complications accountable for early and late graft dysfunction. Tabulation of clinico-pathological features to distinguish various complications helps to solve the conundrums and arrive at the correct diagnosis.