Inducible knockout of Clec16a in mice results in sensory neurodegeneration

AbstractCLEC16A has been shown to play a role in autophagy/mitophagy processes. Additionally, genetic variants in CLEC16A have been implicated in multiple autoimmune diseases. We generated an inducible whole-body knockout, Clec16aΔUBC mice, to investigate the loss of function of CLEC16A. The mice exhibited a neuronal phenotype including tremors and impaired gait that rapidly progressed to dystonic postures. Nerve conduction studies and pathological analysis revealed loss of sensory axons that are associated with this phenotype. Activated microglia and astrocytes were found in regions of the CNS. Several mitochondrial-related proteins were up- or down-regulated. Upregulation of interferon stimulated gene 15 (IGS15) were observed in neuronal tissues. CLEC16A expression inversely related to IGS15 expression. ISG15 may be the link between CLEC16A and downstream autoimmune, inflammatory processes. Our results demonstrate that a whole-body, inducible knockout of Clec16a in mice results in an inflammatory neurodegenerative phenotype resembling spinocerebellar ataxia.

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Treatment with Melittin Induces Apoptosis and Autophagy of Fibroblast-like Synoviocytes in Patients with Rheumatoid Arthritis

Current Pharmaceutical Biotechnology ◽

10.2174/1389201021666191210110826 ◽

2020 ◽

Vol 21 (8) ◽

pp. 734-740 ◽

Cited By ~ 1

Author(s):

Shou-di He ◽

Ning Tan ◽

Chen-xia Sun ◽

Kang-han Liao ◽

Hui-jun Zhu ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Caspase 3 ◽

Joint Destruction ◽

Joint Disease ◽

Enzyme Linked Immunosorbent Assay ◽

Caspase 9 ◽

Inflammatory Processes ◽

Related Proteins ◽

Local Stimulation ◽

Fibroblast Like Synoviocytes

Background: Melittin, the major medicinal component of honeybee venom, exerts antiinflammatory, analgesic, and anti-arthritic effects in patients with Rheumatoid Arthritis (RA). RA is an inflammatory autoimmune joint disease that leads to irreversible joint destruction and functional loss. Fibroblast-Like Synoviocytes (FLS) are dominant, special mesenchymal cells characterized by the structure of the synovial intima, playing a crucial role in both the initiation and progression of RA. Objective: In this study, we evaluated the effects of melittin on the viability and apoptosis of FLS isolated from patients with RA. Methods: Cell viability was determined using CCK-8 assays; apoptosis was evaluated by flow cytometry, and the expression levels of apoptosis-related proteins (caspase-3, caspase-9, BAX, and Bcl-2) were also determined. To explore whether melittin alters inflammatory processes in RA-FLS, IL-1β levels were determined using an enzyme-linked immunosorbent assay (ELISA). Furthermore, we performed GFP-LC3 punctate fluorescence dot assays and western blotting (for LC3, ATG5, p62, and Beclin 1) to assess autophagy in RA-FLS. Results: Our results show that melittin can significantly impair viability, promote apoptosis and autophagy, and inhibit IL-1β secretion in RA-FLS. Conclusion: Melittin may be useful in preventing damage to the joints during accidental local stimulation.

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Actin-Related Protein 4 Interacts with PIE1 and Regulates Gene Expression in Arabidopsis

Genes ◽

10.3390/genes12040520 ◽

2021 ◽

Vol 12 (4) ◽

pp. 520

Author(s):

Wenfeng Nie ◽

Jinyu Wang

Keyword(s):

Gene Expression ◽

Plant Growth ◽

Chromatin Remodeling ◽

Leaf Size ◽

Early Flowering ◽

Physical Interaction ◽

Loss Of Function ◽

Single Nucleotide Change ◽

Chromatin Remodeling Complex ◽

Related Proteins

As essential structural components of ATP-dependent chromatin-remodeling complex, the nucleolus-localized actin-related proteins (ARPs) play critical roles in many biological processes. Among them, ARP4 is identified as an integral subunit of chromatin remodeling complex SWR1, which is conserved in yeast, humans and plants. It was shown that RNAi mediated knock-down of Arabidopsis thaliana ARP4 (AtARP4) could affect plant development, specifically, leading to early flowering. However, so far, little is known about how ARP4 functions in the SWR1 complex in plant. Here, we identified a loss-of-function mutant of AtARP4 with a single nucleotide change from glycine to arginine, which had significantly smaller leaf size. The results from the split luciferase complementation imaging (LCI) and yeast two hybrid (Y2H) assays confirmed its physical interaction with the scaffold and catalytic subunit of SWR1 complex, photoperiod-independent early flowering 1 (PIE1). Furthermore, mutation of AtARP4 caused altered transcription response of hundreds of genes, in which the number of up-regulated differentially expressed genes (DEGs) was much larger than those down-regulated. Although most DEGs in atarp4 are related to plant defense and response to hormones such as salicylic acid, overall, it has less overlapping with other swr1 mutants and the hta9 hta11 double-mutant. In conclusion, our results reveal that AtARP4 is important for plant growth and such an effect is likely attributed to its repression on gene expression, typically at defense-related loci, thus providing some evidence for the coordination of plant growth and defense, while the regulatory patterns and mechanisms are distinctive from other SWR1 complex components.

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A Melanocortin-4 Receptor Agonist Induces Skin and Hair Pigmentation in Patients with Monogenic Mutations in the Leptin-Melanocortin Pathway

Skin Pharmacology and Physiology ◽

10.1159/000516282 ◽

2021 ◽

pp. 1-10

Author(s):

Varvara Kanti ◽

Lia Puder ◽

Irina Jahnke ◽

Philipp Maximilian Krabusch ◽

Jan Kottner ◽

...

Keyword(s):

Leptin Receptor ◽

Skin Pigmentation ◽

Gene Mutations ◽

Continuous Treatment ◽

Whole Body ◽

Hair Color ◽

Phase 2 ◽

Loss Of Function ◽

The Impact ◽

Over Time

Background and Objectives: Gene mutations within the leptin-melanocortin signaling pathway lead to severe early-onset obesity. Recently, a phase 2 trial evaluated new pharmacological treatment options with the MC4R agonist setmelanotide in patients with mutations in the genes encoding proopiomelanocortin (POMC) and leptin receptor (LEPR). During treatment with setmelanotide, changes in skin pigmentation were observed, probably due to off-target effects on the closely related melanocortin 1 receptor (MC1R). Here, we describe in detail the findings of dermatological examinations and measurements of skin pigmentation during this treatment over time and discuss the impact of these changes on patient safety. Methods: In an investigator-initiated, phase 2, open-label pilot study, 2 patients with loss-of-function POMC gene mutations and 3 patients with loss-of-function variants in LEPR were treated with the MC4R agonist setmelanotide. Dermatological examination, dermoscopy, whole body photographic documentation, and spectrophotometric measurements were performed at screening visit and approximately every 3 months during the course of the study. Results: We report the results of a maximum treatment duration of 46 months. Skin pigmentation increased in all treated patients, as confirmed by spectrophotometry. During continuous treatment, the current results indicate that elevated tanning intensity levels may stabilize over time. Lips and nevi also darkened. In red-haired study participants, hair color changed to brown after initiation of setmelanotide treatment. Discussion: Setmelanotide treatment leads to skin tanning and occasionally hair color darkening in both POMC- and LEPR-deficient patients. No malignant skin changes were observed in the patients of this study. However, the results highlight the importance of regular skin examinations before and during MC4R agonist treatment.

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Abstract 15813: Loss-of-Function Mutation in Toll-Like Receptor 4 Partially Protects Against Peripheral and Cardiac Insulin Resistance During a Long-Term High-Fat Diet

Circulation ◽

10.1161/circ.130.suppl_2.15813 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Ellen Jackson ◽

Elizabeth Rendina-Ruedy ◽

Matt Priest ◽

Brenda Smith ◽

Veronique Lacombe

Keyword(s):

Insulin Resistance ◽

Protein Content ◽

Glucose Transport ◽

High Fat Diet ◽

Whole Body ◽

Toll Like Receptor ◽

Loss Of Function ◽

High Fat ◽

The Face ◽

Tlr4 Activation

Diabetes mellitus is an epidemic disease characterized by alterations in glucose transport, which is tightly regulated by a family of specialized proteins called the glucose transporters (GLUTs). Although diabetic cardiomyopathy is a common complication in diabetic patients, its pathogenesis is still not well understood. Toll-like receptor (TLR) 4, which plays a central role in pathogen recognition by the innate immune system, may also play a critical role in linking inflammation and metabolic disease. We hypothesized that TLR4 activation triggers cardiac insulin resistance. We used mice with a loss-of function mutation in TLR4 (C3H/HeJ) and age-matched wild-type (WT, C57BL/6N) mice (n=8/group) to investigate how feeding a high-fat diet (HFD, 60% kcal from fat) for 16 weeks affected whole-body and cardiac glucose metabolism. After 16 weeks, WT mice fed a HFD were obese and developed hyperglycemia and insulin resistance compared to WT mice on a control diet (10% kcal from fat). The C3H/HeJ mice were partially protected against HFD-induced obesity and insulin resistance. In the heart, WT mice fed a HFD had a 30% decrease (P<0.05) in GLUT4 protein content as measured by Western Blot of cardiac crude membrane protein extracts. In contrast, the loss-of-function point mutation in TLR4 partially rescued cardiac GLUT4 content in the face of a HFD. Interestingly, there was a 40% increase (P<0.05) in the novel GLUT isoform, GLUT8, in the heart when mice of either genotype were fed a HFD. Additionally, GLUT4 protein content was negatively (P<0.05) correlated with GLUT8 content in the myocardium, suggesting that GLUT8 may act as a compensatory mechanism in the face of HFD-induced GLUT4 downregulation. Phosphorylated Akt, a key protein of the insulin signaling pathway, was positively (P<0.05) correlated with GLUT4 content, while the basal/inactive form was negatively correlated. In conclusion, these data suggest that activation of TLR4 activation during diabetes and obesity alters glucose transport by an Akt mechanism, and as such is a pathogenic factor during peripheral and cardiac insulin resistance. Overall, TLR4 appears to be a key modulator in the cross-talk between inflammatory and metabolic pathways, as well as a potential therapeutic target for diabetes.

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Converging physiological roles of the anthrax toxin receptors

F1000Research ◽

10.12688/f1000research.19423.1 ◽

2019 ◽

Vol 8 ◽

pp. 1415

Author(s):

Oksana A. Sergeeva ◽

F. Gisou van der Goot

Keyword(s):

Anthrax Toxin ◽

Loss Of Function ◽

Disease Symptoms ◽

Hyaline Fibromatosis Syndrome ◽

Anthrax Toxins ◽

The Difference ◽

Related Proteins ◽

Tumor Endothelial Marker 8 ◽

Insight Into ◽

Shed Light

The anthrax toxin receptors—capillary morphogenesis gene 2 (CMG2) and tumor endothelial marker 8 (TEM8)—were identified almost 20 years ago, although few studies have moved beyond their roles as receptors for the anthrax toxins to address their physiological functions. In the last few years, insight into their endogenous roles has come from two rare diseases: hyaline fibromatosis syndrome, caused by mutations in CMG2, and growth retardation, alopecia, pseudo-anodontia, and optic atrophy (GAPO) syndrome, caused by loss-of-function mutations in TEM8. Although CMG2 and TEM8 are highly homologous at the protein level, the difference in disease symptoms points to variations in the physiological roles of the two anthrax receptors. Here, we focus on the similarities between these receptors in their ability to regulate extracellular matrix homeostasis, angiogenesis, cell migration, and skin elasticity. In this way, we shed light on how mutations in these two related proteins cause such seemingly different diseases and we highlight the existing knowledge gaps that could form the focus of future studies.

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Saccharomyces cerevisiae kinesin- and dynein-related proteins required for anaphase chromosome segregation.

The Journal of Cell Biology ◽

10.1083/jcb.128.4.617 ◽

1995 ◽

Vol 128 (4) ◽

pp. 617-624 ◽

Cited By ~ 137

Author(s):

W S Saunders ◽

D Koshland ◽

D Eshel ◽

I R Gibbons ◽

M A Hoyt

Keyword(s):

Saccharomyces Cerevisiae ◽

Chromosome Segregation ◽

Motor Proteins ◽

Cytoplasmic Dynein ◽

Gene Products ◽

Loss Of Function ◽

Direct Role ◽

Double Deletion ◽

Different Types ◽

Related Proteins

The Saccharomyces cerevisiae kinesin-related gene products Cin8p and Kip1p function to assemble the bipolar mitotic spindle. The cytoplasmic dynein heavy chain homologue Dyn1p (also known as Dhc1p) participates in proper cellular positioning of the spindle. In this study, the roles of these motor proteins in anaphase chromosome segregation were examined. While no single motor was essential, loss of function of all three completely halted anaphase chromatin separation. As combined motor activity was diminished by mutation, both the velocity and extent of chromatin movement were reduced, suggesting a direct role for all three motors in generating a chromosome-separating force. Redundancy for function between different types of microtubule-based motor proteins was also indicated by the observation that cin8 dyn1 double-deletion mutants are inviable. Our findings indicate that the bulk of anaphase chromosome segregation in S. cerevisiae is accomplished by the combined actions of these three motors.

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Viral Hepatitis and Iron Dysregulation: Molecular Pathways and the Role of Lactoferrin

Molecules ◽

10.3390/molecules25081997 ◽

2020 ◽

Vol 25 (8) ◽

pp. 1997 ◽

Cited By ~ 4

Author(s):

Romina Mancinelli ◽

Luigi Rosa ◽

Antimo Cutone ◽

Maria Stefania Lepanto ◽

Antonio Franchitto ◽

...

Keyword(s):

Viral Hepatitis ◽

Viral Entry ◽

Iron Homeostasis ◽

Iron Chelation ◽

Host Cells ◽

Surface Receptors ◽

Inflammatory Processes ◽

Related Proteins ◽

Binding Glycoprotein

The liver is a frontline immune site specifically designed to check and detect potential pathogens from the bloodstream to maintain a general state of immune hyporesponsiveness. One of the main functions of the liver is the regulation of iron homeostasis. The liver detects changes in systemic iron requirements and can regulate its concentration. Pathological states lead to the dysregulation of iron homeostasis which, in turn, can promote infectious and inflammatory processes. In this context, hepatic viruses deviate hepatocytes’ iron metabolism in order to better replicate. Indeed, some viruses are able to alter the expression of iron-related proteins or exploit host receptors to enter inside host cells. Lactoferrin (Lf), a multifunctional iron-binding glycoprotein belonging to the innate immunity, is endowed with potent antiviral activity, mainly related to its ability to block viral entry into host cells by interacting with viral and/or cell surface receptors. Moreover, Lf can act as an iron scavenger by both direct iron-chelation or the modulation of the main iron-related proteins. In this review, the complex interplay between viral hepatitis, iron homeostasis, and inflammation as well as the role of Lf are outlined.

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CTRP3 deficiency reduces liver size and alters IL-6 and TGFβ levels in obese mice

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00248.2015 ◽

2016 ◽

Vol 310 (5) ◽

pp. E332-E345 ◽

Cited By ~ 28

Author(s):

Risa M. Wolf ◽

Xia Lei ◽

Zhi-Chun Yang ◽

Maeva Nyandjo ◽

Stefanie Y. Tan ◽

...

Keyword(s):

Serum Levels ◽

Whole Body ◽

Activity Levels ◽

Loss Of Function ◽

Physiological Control ◽

Liver Size ◽

Male And Female ◽

Female Mice ◽

Obesity And Diabetes ◽

Similar Weight

C1q/TNF-related protein 3 (CTRP3) is a secreted metabolic regulator whose circulating levels are reduced in human and rodent models of obesity and diabetes. Previously, we showed that CTRP3 infusion lowers blood glucose by suppressing gluconeogenesis and that transgenic overexpression of CTRP3 protects mice against diet-induced hepatic steatosis. Here, we used a genetic loss-of-function mouse model to further address whether CTRP3 is indeed required for metabolic homeostasis under normal and obese states. Both male and female mice lacking CTRP3 had similar weight gain when fed a control low-fat (LFD) or high-fat diet (HFD). Regardless of diet, no differences were observed in adiposity, food intake, metabolic rate, energy expenditure, or physical activity levels between wild-type (WT) and Ctrp3-knockout (KO) animals of either sex. Contrary to expectations, loss of CTRP3 in LFD- or HFD-fed male and female mice also had minimal or no impact on whole body glucose metabolism, insulin sensitivity, and fasting-induced hepatic gluconeogenesis. Unexpectedly, the liver sizes of HFD-fed Ctrp3-KO male mice were markedly reduced despite a modest increase in triglyceride content. Furthermore, liver expression of fat oxidation genes was upregulated in the Ctrp3-KO mice. Whereas the liver and adipose expression of profibrotic TGFβ1, as well as its serum levels, was suppressed in HFD-fed KO mice, circulating proinflammatory IL-6 levels were markedly increased; these changes, however, were insufficient to affect systemic metabolic outcome. We conclude that, although it is dispensable for physiological control of energy balance, CTRP3 plays a previously unsuspected role in modulating liver size and circulating cytokine levels in response to obesity.

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Loss of PDGF-B activity increases hepatic vascular permeability and enhances insulin sensitivity

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00241.2011 ◽

2011 ◽

Vol 301 (3) ◽

pp. E517-E526 ◽

Cited By ~ 27

Author(s):

Summer M. Raines ◽

Oliver C. Richards ◽

Lindsay R. Schneider ◽

Kathryn L. Schueler ◽

Mary E. Rabaglia ◽

...

Keyword(s):

Insulin Sensitivity ◽

Insulin Signaling ◽

Insulin Action ◽

Basolateral Membrane ◽

Tolerance Test ◽

Whole Body ◽

Glucose Disposal ◽

Permeability Barrier ◽

Loss Of Function ◽

Transendothelial Transport

Hepatic vasculature is not thought to pose a permeability barrier for diffusion of macromolecules from the bloodstream to hepatocytes. In contrast, in extrahepatic tissues, the microvasculature is critically important for insulin action, because transport of insulin across the endothelial cell layer is rate limiting for insulin-stimulated glucose disposal. However, very little is known concerning the role in this process of pericytes, the mural cells lining the basolateral membrane of endothelial cells. PDGF-B is a growth factor involved in the recruitment and function of pericytes. We studied insulin action in mice expressing PDGF-B lacking the proteoglycan binding domain, producing a protein with a partial loss of function (PDGF-B ret/ ret). Insulin action was assessed through measurements of insulin signaling and insulin and glucose tolerance tests. PDGF-B deficiency enhanced hepatic vascular transendothelial transport. One outcome of this change was an increase in hepatic insulin signaling. This correlated with enhanced whole body glucose homeostasis and increased insulin clearance from the circulation during an insulin tolerance test. In obese mice, PDGF-B deficiency was associated with an 80% reduction in fasting insulin and drastically reduced insulin secretion. These mice did not have significantly higher glucose levels, reflecting a dramatic increase in insulin action. Our findings show that, despite already having a high permeability, hepatic transendothelial transport can be further enhanced. To the best of our knowledge, this is the first study to connect PDGF-B-induced changes in hepatic sinusoidal transport to changes in insulin action, demonstrating a link between PDGF-B signaling and insulin sensitivity.

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Cryostimulation of whole body as a possible supportive biological approach in mild cognitive impairments

European Psychiatry ◽

10.1016/j.eurpsy.2016.01.065 ◽

2016 ◽

Vol 33 (S1) ◽

pp. S95-S95

Author(s):

J. Rymaszewska ◽

D. Szczesniak ◽

U. Katarzyna ◽

T. Elzbieta ◽

S. Bartlomiej

Keyword(s):

Cognitive Impairments ◽

Vascular Lesions ◽

Whole Body ◽

Inflammatory Processes ◽

Competing Interest ◽

Future Evaluation ◽

Therapy Strategies ◽

Whole Body Cryotherapy ◽

Experimental Group

BackgroundLimitations of available treatment methods of dementia imply constant need to search for new, supplementary therapy strategies. There is a consensus that vascular lesions, oxidative stress, inflammatory processes and abnormal neurotransmission are associated with dementia. Due to the anti-inflammatory (modification of pro-inflammatory cytokines concentration), antioxidative effect of cryogenic temperatures as well as the hormonal and lipid changes, they may play an important role in preventing or inhibiting pathophysiological processes.AimTo assess the influence of whole-body cryostimulation on cognitive functions of patients with MCI.MethodsRCT design is used to examine the influence of whole-body cryotherapy (WBC) on people with mild cognitive impairments (MCI) with the evaluation of psychometric, somatic and laboratory parameters. Participants undergo 10 sessions each day of 2–3 min of WBC in experimental group (−110 till −160 °C) and placebo (−20 °C). The CDR, MoCA, TYM, DemTect and SLUMS scales are used among others at baseline and follow-up. Preliminary data of 7 volunteers (n = 7, 49–79 years old) were presented. Results on Fig. 1.DiscussionAmong obtained psychometric results show that all, except of one, patients significantly improved their scores after WBC. That is a very promising feedback for future evaluation of WBC effectiveness in prevention of dementia in patients with MCI.Disclosure of interestThe authors have not supplied their declaration of competing interest.

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