The potential therapeutic effect of manipulating the extracellular matrix in idiopathic pulmonary fibrosis

Background: Idiopathic Pulmonary Fibrosis (IPF) is a physiologically devastating disease. The debilitating nature and high mortality rates make this one of the most lethal conditions, usually associated with median time to mortality of around 3 years. Increased deposition of extracellular matrix (ECM) and fibroblast accumulation are hallmarks of idiopathic pulmonary fibrosis (IPF). We hypothesise that the ECM in IPF is structurally abnormal by virtue of aberrant cross linking and promotes fibroblast accumulation. This study examined the structure and biological activity of IPF derived ECM and how this related to the expression of ECM cross linking enzymes as well as how inhibiting Transglutaminase 2 affects active fibrosis in the murine Bleomycin model. Methods: Primary fibroblasts from 3 patients with IPF and 3 controls were isolated from biopsy samples and characterised by immunocytochemistry. ECM from these cells was deposited onto tissue culture plastic, cells removed using ammonium hydroxide and confirmed by electron microscopy (SEM). IPF and control cells were then grown on their own ECM or ECM derived from other cells. ECM was labelled with 3H-proline and digested with recombinant proteases and tritium liberation counted by scintillation as a measure of collagen proteolysis. A pilot study was carried out where C57BL/5J mice received a single intratracheal instillation of Bleomycin (2mg/kg) and administered cystamine dihydrochloride by intraperitoneal injection (IP), once a day for ten consecutive days at 40mg/kg or 100mg/kg, at 3 different time points. Results: IPF derived fibroblasts had more distinct organisation of fibrous matrix filaments on the cell surface and between adjacent cells by SEM. Both control and IPF lung fibroblasts expressed transcripts for lysyl oxidase (LOX), LOXL1, LOXL2, LOXL3, LOXL4 and transglutaminase (TG) 2. IPF derived matrix increased expression of LOXL3 and TG2 transcripts, LOXL3 protein and TGase activity. Other cross linking enzymes were unchanged. To assess if IPF matrix affected fibroblast accumulation, I measured fibroblast adhesion, proliferation by MTT and EDU assays, and apoptosis by cleaved caspase 3, cleaved PARP and TUNEL assay on the different matrices. IPF matrix enhanced proliferation over control matrix in response to PDGF-BB. To determine if this pro-proliferative effect was dependent upon aberrant cross-linking we generated ECM from normal and IPF fibroblasts treated with cystamine dihydrochloride (TG2 inhibitor) or β-amino-proprionitrile (LOX family inhibitor). The enhanced fibroblast proliferation seen on IPF matrix was reduced close to levels of normal matrix by each cross link inhibitor. There was no effect on apoptosis induced by either FAS ligand or staurosporine when cells were seeded onto IPF or control matrix suggesting IPF ECM does not protect seeded fibroblasts from apoptosis. Bleomycin showed a trend towards increasing total lung hydroxyproline at day 24, 34 and 44 post administration however this was not statistically significant. Administration of cystamine at 40mg/kg/day showed no effect on total lung hydroxyproline. At day 34 post Bleomycin, cystamine administration showed a trend towards decreasing total lung hydroxyproline however again this was not statistically significant. Conclusions: The data supports the hypothesis that IPF derived matrix is structurally and functionally different from normal matrix. This results in enhanced fibroblast proliferation, adhesion and increased cross linking activity by effects on gene transcription. Inhibition of matrix cross-linking reduced this enhanced fibroblast adhesion and proliferation. Administration of cystamine dihydrochloride via IP injection for ten consecutive days at 100mg/kg/day in the Bleomycin model showed a trend towards decreasing total lung hydroxyproline

Beneficial Effects of Resistance Exercise on Glycemic Control Are Not Further Improved by Protein Ingestion

Purpose: To investigate the mechanisms underpinning modifications in glucose homeostasis and insulin sensitivity 24 h after a bout of resistance exercise (RE) with or without protein ingestion. Methods: Twenty-four healthy males were assigned to a control (CON; n = 8), exercise (EX; n = 8) or exercise plus protein condition (EX+PRO; n = 8). Muscle biopsy and blood samples were obtained at rest for all groups and immediately post-RE (75% 1RM, 8×10 repetitions of leg-press and extension exercise) for EX and EX+PRO only. At 24 h post-RE (or post-resting biopsy for CON), a further muscle biopsy was obtained. Participants then consumed an oral glucose load (OGTT) containing 2 g of [U-13C] glucose during an infusion of 6, 6-[2H2] glucose. Blood samples were obtained every 10 min for 2 h to determine glucose kinetics. EX+PRO ingested an additional 25 g of intact whey protein with the OGTT. A final biopsy sample was obtained at the end of the OGTT. Results: Fasted plasma glucose and insulin were similar for all groups and were not different immediately post- and 24 h post-RE. Following RE, muscle glycogen was 26±8 and 19±6% lower in EX and EX+PRO, respectively. During OGTT, plasma glucose AUC was lower for EX and EX+PRO (75.1±2.7 and 75.3±2.8 mmol·L-1:120 min, respectively) compared with CON (90.6±4.1 mmol·L-1:120 min). Plasma insulin response was 13±2 and 21±4% lower for EX and CON, respectively, compared with EX+PRO. Glucose disappearance from the circulation was ~12% greater in EX and EX+PRO compared with CON. Basal 24 h post-RE and insulin-stimulated PAS-AS160/TBC1D4 phosphorylation was greater for EX and EX+PRO. Conclusions: Prior RE improves glycemic control and insulin sensitivity through an increase in the rate at which glucose is disposed from the circulation. However, co-ingesting protein during a high-glucose load does not augment this response at 24 h post-exercise in healthy, insulin-sensitive individuals

Training with low muscle glycogen enhances fat metabolism in well-trained cyclists

Purpose: To determine the effects of training with low muscle glycogen on exercise performance, substrate metabolism, and skeletal muscle adaptation. Methods: Fourteen well-trained cyclists were pair-matched and randomly assigned to HIGH-or LOW-glycogen training groups. Subjects performed nine aerobic training (AT; 90 min at 70% (V) over dotO(2max)) and nine high-intensity interval training sessions (HIT; 8 x 5-min efforts, 1-min recovery) during a 3-wk period. HIGH trained once daily, alternating between AT on day 1 and HIT the following day, whereas LOW trained twice every second day, first performing AT and then, 1 h later, performing HIT. Pretraining and posttraining measures were a resting muscle biopsy, metabolic measures during steady-state cycling, and a time trial. Results: Power output during HIT was 297 +/- 8 W in LOW compared with 323 +/- 9 W in HIGH (P < 0.05); however, time trial performance improved by similar to 10% in both groups (P < 0.05). Fat oxidation during steady-state cycling increased after training in LOW (from 26 +/- 2 to 34 +/- 2 mu mol.kg(-1).min(-1), P < 0.01). Plasma free fatty acid oxidation was similar before and after training in both groups, but muscle-derived triacylglycerol oxidation increased after training in LOW (from 16 +/- 1 to 23 +/- 1 mu mol.kg(-1).min(-1), P < 0.05). Training with low muscle glycogen also increased beta-hydroxyacyl-CoA-dehydrogenase protein content (P < 0.01). Conclusions: Training with low muscle glycogen reduced training intensity and, in performance, was no more effective than training with high muscle glycogen. However, fat oxidation was increased after training with low muscle glycogen, which may have been due to the enhanced metabolic adaptations in skeletal muscle

High Density of Tumor-Associated Macrophage Staining Correlates with Poor Clinicopathologic Markers in Head and Neck Squamous Cell Carcinoma: A Meta-Analysis

Background: Head and neck squamous cell carcinoma (HNSCC) develops within a complex cellular microenvironment that promotes tumor growth, but also represents many potential therapeutic targets. Macrophage presence within that environment has been implicated in the growth, aggression, and persistence of HNSCC. Current literature reports variable degrees of association between tumor-associated macrophage (TAMs) density and clinicopathologic markers of disease.Inconsistent findings may result from grouping of TAM subtypes, which include both M1 (pro-inflammatory) and M2 (immunosuppressive). Our aim is to define the prognostic significance of the phenotypes of tumor-associated macrophages in HNSCC. Methods: We conducted a meta-analysis of the existing publications investigating the relationship between TAMs (total and M2 subtype) and T stage, nodal involvement, vascular invasion, lymphatic invasion, and tumor differentiation. Forest plots and risk ratios were generated to report overall effect. Results: Higher density of both total and M2 subtype of TAMs in the tumor microenvironment is associated with advanced T stage, increased rates of nodal positivity, presence of vascular invasion, and presence of lymphatic invasion (p \u3c 0.0001). There is no significant association between either total or M2 TAM density and tumor differentiation. Conclusion: Increased density of TAMs, including those of the M2 phenotype, correlates with poor clinicopathologic markers in HNSCC, and therefore poor clinical prognosis. It is unknown whether this relationship is causative or correlative. Additional investigation into the mechanisms behind TAM recruitment and differentiation, and effect of TAM population manipulation on tumor behavior will help define the feasibility of TAM-targeted therapies

MMP-1 activation contributes to airway smooth muscle growth and asthma severity

Introduction: Matrix metalloproteinase-1 and mast cells are present in the airways of people with asthma. We hypothesised that matrix metalloproteinase-1 could be activated by mast cells and increase asthma severity. Methods: Patients with stable asthma and healthy controls underwent spirometry, methacholine challenge, bronchoscopy and their airway smooth muscle cells were grown in culture. A second asthma group and controls had symptom scores, spirometry and bronchoalveolar lavage before and after rhinovirus-induced asthma exacerbations. Extra-cellular matrix was prepared from decellularised airway smooth muscle cultures. Matrix metalloproteinase-1 protein and activity were assessed. Results: Airway smooth muscle cells generated pro-matrix metalloproteinase-1 which was proteolytically activated by mast cell tryptase. Airway smooth muscle treated with activated mast cell supernatants produced extra-cellular matrix which enhanced subsequent airway smooth muscle growth by 1.5 fold (p<0.05) which was dependent on matrix metalloproteinase-1 activation. In asthma, airway pro-matrix metalloproteinase-1 was 5.4 fold higher than control subjects (p=0.002). Mast cell numbers were associated with airway smooth muscle proliferation and matrix metalloproteinase-1 protein associated with bronchial hyper-responsiveness. During exacerbations, matrix metalloproteinase-1 activity increased and was associated with fall in FEV1 and worsening asthma symptoms. Conclusions: Matrix metalloproteinase-1 is activated by mast cell tryptase resulting in a pro-proliferative extra-cellular matrix. In asthma, mast cells are associated with airway smooth muscle growth, matrix metalloproteinase-1 levels are associated with bronchial hyper-responsiveness and matrix metalloproteinase-1 activation with exacerbation severity. Our findings suggest that airway smooth muscle/mast cell interactions contribute to asthma severity by transiently increasing matrix metalloproteinase activation, airway smooth muscle growth and airway responsiveness

Head-to-head comparison of BAM15, semaglutide, rosiglitazone, NEN, and calorie restriction on metabolic physiology in female <i>db/db</i> mice

Metabolic disorders such as type 2 diabetes, fatty liver disease, hyperlipidemia, and obesity commonly co-occur but clinical treatment options do not effectively target all disorders. Calorie restriction, semaglutide, rosiglitazone, and mitochondrial uncouplers have all demonstrated efficacy against one or more obesity-related metabolic disorders, but it currently remains unclear which therapeutic strategy best targets the combination of hyperglycaemia, liver fat, hypertriglyceridemia, and adiposity. Herein we performed a head-to-head comparison of 5 treatment interventions in the female db/db mouse model of severe metabolic disease. Treatments included ∼60 % calorie restriction (CR), semaglutide, rosiglitazone, BAM15, and niclosamide ethanolamine (NEN). Results showed that BAM15 and CR improved body weight and liver steatosis to levels superior to semaglutide, NEN, and rosiglitazone, while BAM15, semaglutide, and rosiglitazone improved glucose tolerance better than CR and NEN. BAM15, CR, semaglutide, and rosiglitazone all had efficacy against hypertriglyceridaemia. These data provide a comprehensive head-to-head comparison of several key treatment strategies for metabolic disease and highlight the efficacy of mitochondrial uncoupling to correct multiple facets of the metabolic disease milieu in female db/db mice.</p

Sodium in the dermis colocates to glycosaminoglycan scaffold, with diminishment in type 2 diabetes mellitus

BACKGROUND. Dietary sodium intake mismatches urinary sodium excretion over prolonged periods. Our aims were to localize and quantify electrostatically bound sodium within human skin using triple-quantum–filtered (TQF) protocols for MRI and magnetic resonance spectroscopy (MRS) and to explore dermal sodium in type 2 diabetes mellitus (T2D). METHODS. We recruited adult participants with T2D (n = 9) and euglycemic participants with no history of diabetes mellitus (n = 8). All had undergone lower limb amputations or abdominal skin reduction surgery for clinical purposes. We used 20 μm in-plane resolution 1H MRI to visualize anatomical skin regions ex vivo from skin biopsies taken intraoperatively, 23Na TQF MRI/MRS to explore distribution and quantification of freely dissolved and bound sodium, and inductively coupled plasma mass spectrometry to quantify sodium in selected skin samples. RESULTS. Human dermis has a preponderance (>90%) of bound sodium that colocalizes with the glycosaminoglycan (GAG) scaffold. Bound and free sodium have similar anatomical locations. T2D associates with a severely reduced dermal bound sodium capacity. CONCLUSION. We provide the first evidence to our knowledge for high levels of bound sodium within human dermis, colocating to the GAG scaffold, consistent with a dermal “third space repository” for sodium. T2D associates with diminished dermal electrostatic binding capacity for sodium

Monocarboxylate Transporter 4 (MCT4) Knockout Mice Have Attenuated 4NQO Induced Carcinogenesis; A Role for MCT4 in Driving Oral Squamous Cell Cancer

Head and neck squamous cell carcinoma (HNSCC) is the 6th most common human cancer and affects approximately 50,000 new patients every year in the US. The major risk factors for HNSCC are tobacco and alcohol consumption as well as oncogenic HPV infections. Despite advances in therapy, the overall survival rate for all-comers is only 50%. Understanding the biology of HNSCC is crucial to identifying new biomarkers, implementing early diagnostic approaches and developing novel therapies. As in several other cancers, HNSCC expresses elevated levels of MCT4, a member of the SLC16 family of monocarboxylate transporters. MCT4 is a H+-linked lactate transporter which functions to facilitate lactate efflux from highly glycolytic cells. High MCT4 levels in HNSCC have been associated with poor prognosis, but the role of MCT4 in the development and progression of this cancer is still poorly understood. In this study, we used 4-nitroquinoline-1-oxide (4NQO) to induce oral cancer in MCT4−/− and wild type littermates, recapitulating the disease progression in humans. Histological analysis of mouse tongues after 23 weeks of 4NQO treatment showed that MCT4−/− mice developed significantly fewer and less extended invasive lesions than wild type. In mice, as in human samples, MCT4 was not expressed in normal oral mucosa but was detected in the transformed epithelium. In the 4NQO treated mice we detected MCT4 in foci of the basal layer undergoing transformation, and progressively in areas of carcinoma in situ and invasive carcinomas. Moreover, we found MCT4 positive macrophages within the tumor and in the stroma surrounding the lesions in both human samples of HNSCC and in the 4NQO treated animals. The results of our studies showed that MCT4 could be used as an early diagnostic biomarker of HNSCC. Our finding with the MCT4−/− mice suggest MCT4 is a driver of progression to oral squamous cell cancer and MCT4 inhibitors could have clinical benefits for preventing invasive HNSCC

ECM crosslinking enhances fibroblast growth and protects against matrix proteolysis in lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is characterised by accumulation of extra cellular matrix (ECM) proteins and fibroblast proliferation. ECM cross-linking enzymes have been implicated in fibrotic diseases and we hypothesised that the ECM in IPF is abnormally cross-linked which enhances fibroblast growth and resistance to normal ECM turnover. We used a combination of in vitro ECM preparations and in vivo assays to examine the expression of cross-linking enzymes and the effect of their inhibitors on fibroblast growth and ECM turnover. Lysyl oxidase like 1, 2, 3 and 4 were expressed equally in control and IPF derived fibroblasts. Transglutaminase 2 was more strongly expressed in IPF fibroblasts. Lysyl oxidase like 2, transglutaminase 2 and transglutaminase generated cross-links were strongly expressed in IPF lung tissue. Fibroblasts grown on IPF ECM had higher LOXL3 protein expression and transglutaminase activity compared with those grown on control ECM. IPF derived ECM also enhanced fibroblast adhesion and proliferation compared with control ECM. Inhibition of lysyl oxidase and transglutaminse activity during ECM formation affected ECM structure as visualised by electron microscopy and reduced the enhanced fibroblast adhesion and proliferation of IPF ECM to control levels. Inhibition of transglutaminase, but not lysyl oxidase activity, enhanced the turnover of ECM in vitro. In bleomycin treated mice, during the post-inflammatory fibrotic phase, inhibition of transglutaminases was associated with a reduction in whole lung collagen. Our findings suggest that the ECM in IPF may enhance pathological cross-linking which contributes to increased fibroblast growth, resistance to normal ECM turnover to drive lung fibrosis

Spontaneously Resolving Joint Inflammation Is Characterised by Metabolic Agility of Fibroblast-Like Synoviocytes

Fibroblast-like synoviocytes (FLS) play an important role in maintaining joint homeostasis and orchestrating local inflammatory processes. When activated during injury or inflammation, FLS undergo transiently increased bioenergetic and biosynthetic demand. We aimed to identify metabolic changes which occur early in inflammatory disease pathogenesis which might support sustained cellular activation in persistent inflammation. We took primary human FLS from synovial biopsies of patients with very early rheumatoid arthritis (veRA) or resolving synovitis, and compared them with uninflamed control samples from the synovium of people without arthritis. Metabotypes were compared using NMR spectroscopy-based metabolomics and correlated with serum C-reactive protein levels. We measured glycolysis and oxidative phosphorylation by Seahorse analysis and assessed mitochondrial morphology by immunofluorescence. We demonstrate differences in FLS metabolism measurable after ex vivo culture, suggesting that disease-associated metabolic changes are long-lasting. We term this phenomenon ‘metabolic memory’. We identify changes in cell metabolism after acute TNFα stimulation across disease groups. When compared to FLS from patients with early rheumatoid arthritis, FLS from patients with resolving synovitis have significantly elevated mitochondrial respiratory capacity in the resting state, and less fragmented mitochondrial morphology after TNFα treatment. Our findings indicate the potential to restore cell metabotypes by modulating mitochondrial function at sites of inflammation, with implications for treatment of RA and related inflammatory conditions in which fibroblasts play a role