Glucocorticoids modulate TGF-beta production

Corneal fibrosis: From in vitro models to current and upcoming drug and gene medicines

Fibrotic diseases are characterised by myofibroblast differentiation, uncontrolled pathological extracellular matrix accumulation, tissue contraction, scar formation and, ultimately tissue / organ dysfunction. The cornea, the transparent tissue located on the anterior chamber of the eye, is extremely susceptible to fibrotic diseases, which cause loss of corneal transparency and are often associated with blindness. Although topical corticosteroids and antimetabolites are extensively used in the management of corneal fibrosis, they are associated with glaucoma, cataract formation, corneoscleral melting and infection, imposing the need of far more effective therapies. Herein, we summarise and discuss shortfalls and recent advances in in vitro models (e.g. transforming growth factor-β (TGF-β) / ascorbic acid / interleukin (IL) induced) and drug (e.g. TGF-β inhibitors, epigenetic modulators) and gene (e.g. gene editing, gene silencing) therapeutic strategies in the corneal fibrosis context. Emerging therapeutical agents (e.g. neutralising antibodies, ligand traps, receptor kinase inhibitors, antisense oligonucleotides) that have shown promise in clinical setting but have not yet assessed in corneal fibrosis context are also discussed.

The novel molecular mechanism of pulmonary fibrosis: insight into lipid metabolism from reanalysis of single-cell RNA-seq databases

Pulmonary fibrosis (PF) is a severe pulmonary disease with limited available therapeutic choices. Recent evidence increasingly points to abnormal lipid metabolism as a critical factor in PF pathogenesis. Our latest research identifies the dysregulation of low-density lipoprotein (LDL) is a new risk factor for PF, contributing to alveolar epithelial and endothelial cell damage, and fibroblast activation. In this study, we first integrative summarize the published literature about lipid metabolite changes found in PF, including phospholipids, glycolipids, steroids, fatty acids, triglycerides, and lipoproteins. We then reanalyze two single-cell RNA-sequencing (scRNA-seq) datasets of PF, and the corresponding lipid metabolomic genes responsible for these lipids' biosynthesis, catabolism, transport, and modification processes are uncovered. Intriguingly, we found that macrophage is the most active cell type in lipid metabolism, with almost all lipid metabolic genes being altered in macrophages of PF. In type 2 alveolar epithelial cells, lipid metabolic differentially expressed genes (DEGs) are primarily associated with the cytidine diphosphate diacylglycerol pathway, cholesterol metabolism, and triglyceride synthesis. Endothelial cells are partly responsible for sphingomyelin, phosphatidylcholine, and phosphatidylethanolamines reprogramming as their metabolic genes are dysregulated in PF. Fibroblasts may contribute to abnormal cholesterol, phosphatidylcholine, and phosphatidylethanolamine metabolism in PF. Therefore, the reprogrammed lipid profiles in PF may be attributed to the aberrant expression of lipid metabolic genes in different cell types. Taken together, these insights underscore the potential of targeting lipid metabolism in developing innovative therapeutic strategies, potentially leading to extended overall survival in individuals affected by PF.

Regenerative Therapy for Corneal Scarring Disorders

The cornea is a transparent and vitally multifaceted component of the eye, playing a pivotal role in vision and ocular health. It has primary refractive and protective functions. Typical corneal dysfunctions include opacities and deformities that result from injuries, infections, or other medical conditions. These can significantly impair vision. The conventional challenges in managing corneal ailments include the limited regenerative capacity (except corneal epithelium), immune response after donor tissue transplantation, a risk of long-term graft rejection, and the global shortage of transplantable donor materials. This review delves into the intricate composition of the cornea, the landscape of corneal regeneration, and the multifaceted repercussions of scar-related pathologies. It will elucidate the etiology and types of dysfunctions, assess current treatments and their limitations, and explore the potential of regenerative therapy that has emerged in both in vivo and clinical trials. This review will shed light on existing gaps in corneal disorder management and discuss the feasibility and challenges of advancing regenerative therapies for corneal stromal scarring.

Early response to intravenous methylprednisolone therapy for restrictive myopathy in patients with thyroid eye disease

PURPOSE

To report the therapeutic efficacy of intravenous methylprednisolone (IVMP) in patients with restrictive myopathy caused by thyroid eye disease (TED).

METHODS

The present prospective uncontrolled study comprised 28 patients with TED and restrictive myopathy who presented with diplopia that had developed within 6 months before their visit. All patients were treated with IVMP for 12 weeks. Deviation angle, limitation of extraocular muscle (EOM) movement, binocular single vision score, Hess score, clinical activity score (CAS), modified NOSPECS score, exophthalmometric value, and the size of EOMs on computed tomography were evaluated. The patients were divided into two groups: those whose deviation angle had decreased or remained unchanged 6 months after treatment (group 1; n = 17) and those whose deviation angle had increased in that time (group 2; n = 11).

RESULTS

The mean CAS of the whole cohort significantly decreased from baseline to 1 month and 3 months after treatment (P = 0.03 and P = 0.02, respectively). The mean deviation angle significantly increased from baseline to 1, 3, and 6 months (P = 0.01, P < 0.01, and P < 0.01, respectively). The deviation angle decreased in 10 (36%), remained constant in seven (25%), and increased in 11 (39%) of the 28 patients. When groups 1 and 2 were compared, no single variable was identified as a cause of deviation angle deterioration (P > 0.05).

CONCLUSIONS

When treating patients with TED who have restrictive myopathy, physicians should be aware that some patients show worsening of the strabismus angle despite inflammation control with IVMP therapy. Uncontrolled fibrosis can result in motility deterioration.

Future regenerative therapies for corneal disease

PURPOSE OF REVIEW

To highlight the progress and future direction of stem-cell based regenerative therapies for the treatment of corneal disease.

RECENT FINDINGS

Corneal stem cell-based therapies, such as limbal stem cell transplantation, corneal stromal stem cell transplantation, endothelial stem cell transplantation, and stem cell-derived extracellular vesicles have demonstrated promising results in the laboratory. Although most are still in preclinical development or early phase clinical trials, these stem cell-based therapies hold potential to facilitate tissue regeneration, restore native function, and inhibit pathologic disease processes such as fibrosis, inflammation, and neovascularization.

SUMMARY

Stem cell-based therapy offers a promising therapeutic option that can circumvent several of the challenges and limitations of traditional surgical treatment. This concise review summarizes the progress in stem-cell based therapies for corneal diseases along with their history, underlying mechanisms, limitations, and future areas for development.

The Role of Extracellular Vesicles (EVs) in Chronic Graft vs. Host Disease, and the Potential Function of Placental Cell-Derived EVs as a Therapeutic Tool

Chronic graft-versus-host disease (cGVHD) presents with dermal inflammation and fibrosis. We investigated the characteristics of extracellular vesicles (EVs) obtained from cGVHD patients, and their potential effects on human dermal fibroblast (NHDF) cells. The anti-inflammatory and anti-fibrotic effects of placental EVs were also explored given their known anti-inflammatory properties. Fourteen cGVHD patients' EVs contained higher levels of fibrosis-related proteins, TGFβ and α-smooth muscle actin (αSMA), compared to EVs from thirteen healthy subjects. The exposure of NHDF cells to the patients' EVs increased the NHDF cells' TGFβ and αSMA expressions. Placental EVs derived from placental-expanded cells (PLX) (Pluri Inc.) and human villous trophoblast (HVT) cells expressing the mesenchymal markers CD29, CD73, and CD105, penetrated into both the epidermal keratinocytes (HACATs) and NHDF cells. Stimulation of the HACAT cells with cytokine TNFα/INFγ (0.01-0.1 ng/µL) reduced cell proliferation, while the addition of placental EVs attenuated this effect, increasing and normalizing cell proliferation. The treatment of NHDF cells with a combination of TGFβ and placental HVT EVs reduced the stimulatory effects of TGFβ on αSMA production by over 40% (p = 0.0286). In summary, EVs from patients with cGVHD can serve as a biomarker for the cGVHD state. Placental EVs may be used to regulate dermal inflammation and fibrosis, warranting further investigation of their therapeutic potential.

A case of papilledema in Camurati-Engelmann disease treated effectively with prednisolone

Camurati-Engelmann disease (CED) causes bone pain, muscle weakness, and cranial nerve symptoms due to abnormal thickening of the long bones of the limbs and the cortex of the skull. The pathophysiology of CED is a gain-of-function variant of transforming growth factor beta 1 (TGFB1). The ophthalmological symptoms of CED are usually caused by increased intracranial pressure and optic canal stenosis. Here, we report the case of a patient in whom prednisolone was effective against papilledema caused by CED. In this case, when papilledema was observed in both fundi, the patient showed increased bone pain, fever, and elevated CRP and ALP levels. Brain magnetic resonance imaging (MRI) revealed a high short tau inversion recovery (STIR) signal in both optic nerves, suggesting edematous changes. Prednisolone ameliorated bone pain, fever, and papilledema, resulting in a slight improvement of the visual function of the right eye. Our results suggest that prednisolone may be effective in treating ophthalmologic symptoms in addition to bone pain in patients with CED.

Microvascular significance of TGF-β axis activation in COVID-19

As 2023 approaches, the COVID-19 pandemic has killed millions. While vaccines have been a crucial intervention, only a few effective medications exist for prevention and treatment of COVID-19 in breakthrough cases or in unvaccinated or immunocompromised patients. SARS-CoV-2 displays early and unusual features of micro-thrombosis and immune dysregulation that target endothelial beds of the lungs, skin, and other organs. Notably, anticoagulation improves outcomes in some COVID-19 patients. The protein transforming growth factor-beta (TGF-β1) has constitutive roles in maintaining a healthy microvasculature through its roles in regulating inflammation, clotting, and wound healing. However, after infection (including viral infection) TGF-β1 activation may augment coagulation, cause immune dysregulation, and direct a path toward tissue fibrosis. Dysregulation of TGF-β signaling in immune cells and its localization in areas of microvascular injury are now well-described in COVID-19, and such events may contribute to the acute respiratory distress syndrome and skin micro-thrombosis outcomes frequently seen in severe COVID-19. The high concentration of TGF-β in platelets and in other cells within microvascular thrombi, its ability to activate the clotting cascade and dysregulate immune pathways, and its pro-fibrotic properties all contribute to a unique milieu in the COVID-19 microvasculature. This unique environment allows for propagation of microvascular clotting and immune dysregulation. In this review we summarize the physiological functions of TGF-β and detail the evidence for its effects on the microvasculature in COVID-19. In addition, we explore the potential role of existing TGF-β inhibitors for the prevention and treatment of COVID-19 associated microvascular thrombosis and immune dysregulation.

Of Whales and Genes: Unraveling the Physiological Response to Stressors in Belugas (Delphinapterus leucas) at the Molecular Level

Marine mammals, now more than ever, are exposed to environmental and anthropogenic stressors. A better understanding of stress physiology in marine mammals is warranted in order to assist in conservation efforts. This study screened gene expression profiles (cytokines, stress-response markers) in blood samples collected opportunistically under controlled conditions from aquarium belugas during transport and introduction to a novel environment (T/NEnv), participation in out-of-water examinations (OWE) and from wild belugas during live capture–release health assessments (WLCR). Quantitative-PCR was used to measure gene expression involved in physiological and immune responses at different time scales. Linear mixed models with repeated measures and pairwise comparisons were used for analysis. Overall, a generalized down-regulation of relative gene expression when compared to samples collected under behavioral control from aquarium whales or to pre-assessment samples of wild whales was observed, with genes IFNγ, IL2, TGFβ and Nr3c1 displaying the largest significant (p < 0.05) changes. Significant (p < 0.05) negative associations of inflammatory gene expression with norepinephrine suggest inhibitory effects of catecholamines on the inflammatory response. Overall, this study contributes to our understanding of the physiological response to stressors at the molecular level in belugas, and the genes suggested here can further be utilized as additional tools in beluga health assessments and monitoring.

Cell-Free Biological Approach for Corneal Stromal Wound Healing

Corneal opacification is the fourth most common cause of blindness globally behind cataracts, glaucoma, and age-related macular degeneration. The standard treatment of serious corneal scarring is corneal transplantation. Though it is effective for restoring vision, the treatment outcome is not optimal, due to limitations such as long-term graft survival, lifelong use of immunosuppressants, and a loss of corneal strength. Regulation of corneal stromal wound healing, along with inhibition or downregulation of corneal scarring is a promising approach to prevent corneal opacification. Pharmacological approaches have been suggested, however these are fraught with side effects. Tissue healing is an intricate process that involves cell death, proliferation, differentiation, and remodeling of the extracellular matrix. Current research on stromal wound healing is focused on corneal characteristics such as the immune response, angiogenesis, and cell signaling. Indeed, promising new technologies with the potential to modulate wound healing are under development. In this review, we provide an overview of cell-free strategies and some approaches under development that have the potential to control stromal fibrosis and scarring, especially in the context of early intervention.

AP Collagen Peptides Prevent Cortisol-Induced Decrease of Collagen Type I in Human Dermal Fibroblasts

Cortisol is an endogenous glucocorticoid (GC) and primary stress hormone that regulates a wide range of stress responses in humans. The adverse effects of cortisol on the skin have been extensively documented but the underlying mechanism of cortisol-induced signaling is still unclear. In the present study, we investigate the effect of cortisol on collagen type I expression and the effect of AP collagen peptides, collagen tripeptide-rich hydrolysates containing 3% glycine-proline- hydroxyproline (Gly-Pro-Hyp, GPH) from the fish skin, on the cortisol-mediated inhibition of collagen type I and the cortisol-induced signaling that regulates collagen type I production in human dermal fibroblasts (HDFs). We determine that cortisol downregulates the expression of collagen type I. AP collagen peptides or GC receptor (GR) inhibitors recover the cortisol-mediated inhibition of collagen type I and GR activation. AP collagen peptides or GR inhibitors also prevent the cortisol-dependent inhibition of transforming growth factor (TGF)-β signaling. AP collagen peptides or GR inhibitors are effective in the prevention of collagen type I inhibition mediated by cortisol in senescent HDFs and reconstituted human skin models. Taken together, GR signaling might be responsible for the cortisol-mediated inhibition of TGF-β. AP collagen peptides act as GR-mediated signaling blockers, preventing the cortisol-dependent inhibition of collagen type I. Therefore, AP collagen peptides have the potential to improve skin health.

IL-22-dependent dysbiosis and mononuclear phagocyte depletion contribute to steroid-resistant gut graft-versus-host disease in mice

Efforts to improve the prognosis of steroid-resistant gut acute graft-versus-host-disease (SR-Gut-aGVHD) have suffered from poor understanding of its pathogenesis. Here we show that the pathogenesis of SR-Gut-aGVHD is associated with reduction of IFN-γ+ Th/Tc1 cells and preferential expansion of IL-17-IL-22+ Th/Tc22 cells. The IL-22 from Th/Tc22 cells causes dysbiosis in a Reg3γ-dependent manner. Transplantation of IFN-γ-deficient donor CD8+ T cells in the absence of CD4+ T cells produces a phenocopy of SR-Gut-aGVHD. IFN-γ deficiency in donor CD8+ T cells also leads to a PD-1-dependent depletion of intestinal protective CX3CR1hi mononuclear phagocytes (MNP), which also augments expansion of Tc22 cells. Supporting the dual regulation, simultaneous dysbiosis induction and depletion of CX3CR1hi MNP results in full-blown Gut-aGVHD. Our results thus provide insights into SR-Gut-aGVHD pathogenesis and suggest the potential efficacy of IL-22 antagonists and IFN-γ agonists in SR-Gut-aGVHD therapy.

Arthritis and the role of endogenous glucocorticoids

Rheumatoid arthritis and osteoarthritis, the most common forms of arthritis, are chronic, painful, and disabling conditions. Although both diseases differ in etiology, they manifest in progressive joint destruction characterized by pathological changes in the articular cartilage, bone, and synovium. While the potent anti-inflammatory properties of therapeutic (i.e., exogenous) glucocorticoids have been heavily researched and are widely used in clinical practice, the role of endogenous glucocorticoids in arthritis susceptibility and disease progression remains poorly understood. Current evidence from mouse models suggests that local endogenous glucocorticoid signaling is upregulated by the pro-inflammatory microenvironment in rheumatoid arthritis and by aging-related mechanisms in osteoarthritis. Furthermore, these models indicate that endogenous glucocorticoid signaling in macrophages, mast cells, and chondrocytes has anti-inflammatory effects, while signaling in fibroblast-like synoviocytes, myocytes, osteoblasts, and osteocytes has pro-inflammatory actions in rheumatoid arthritis. Conversely, in osteoarthritis, endogenous glucocorticoid signaling in both osteoblasts and chondrocytes has destructive actions. Together these studies provide insights into the role of endogenous glucocorticoids in the pathogenesis of both inflammatory and degenerative joint disease.

Risk of Infection in Trigger Finger Release Surgery Following Corticosteroid Injection

PURPOSE

To determine the risk for infection in trigger finger release surgery after preoperative corticosteroid injection.

METHODS

We retrospectively evaluated all patients undergoing trigger finger release by 16 surgeons over a 2-year period. Data collected included demographic information, medical comorbidities, trigger finger(s) operated on, presence of a prior corticosteroid injection, date of most recent corticosteroid injection, postoperative signs of infection, and need for surgery owing to deep infection. Superficial infection was defined per Centers for Disease Control criteria. Deep infection was defined as the need for surgery related to a surgical site infection.

RESULTS

In this cohort of 2,480 fingers in 1,857 patients undergoing trigger release surgery, 53 (2.1%) developed an infection (41 superficial [1.7%] and 12 deep [0.5%]). Before surgery, 1,137 fingers had no corticosteroid injection. These patients developed 1 deep (0.1%) and 17 superficial (1.5%) infections. In contrast, 1,343 fingers had been given a corticosteroid injection before surgery. These patients developed 11 deep (0.8%) and 24 superficial (1.8%) infections. Median time from corticosteroid injection to trigger release surgery was shorter for fingers that developed a deep infection (63 days) compared with those that developed no infection (183 days). The risk for developing a deep infection in patients who were operated on within 90 days of an injection (8 infections in 395 fingers) was increased compared with patients who were operated on greater than 90 days after an injection (3 infections in 948 fingers).

CONCLUSIONS

Preoperative corticosteroid injections are associated with a small but statistically significantly increased rate of deep infection after trigger finger release surgery. The risk for postoperative deep infection seems to be time dependent and greater when injections are performed within 90 days of surgery, especially in the 31- to 90-day postinjection period.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Systematic Review on Therapeutic Strategies to Minimize Corneal Stromal Scarring After Injury

OBJECTIVES

To evaluate recent studies on available and experimental therapies in preventing or minimizing corneal stromal scarring after injury.

METHODS

We performed an Entrez PubMed literature search using keywords "cornea," "scarring," "haze," "opacity," "ulcer," "treatments," "therapies," "treatment complications," and "pathophysiology" resulting in 390 articles of which 12 were analyzed after filtering, based on English language and publication within 8 years, and curation for relevance by the authors.

RESULTS

The 12 articles selected included four randomized control trials (RCTs) (two were double-blinded placebo-controlled RCTs, one was a prospective partially masked RCT, and one was an open-label RCT), two retrospective observational studies, and six laboratory-based studies including two studies having in vivo and in vitro experiments, one was in vivo study, one was ex vivo study, and the last two were in vitro studies. The current mainstay for preventing or minimizing corneal scarring involves the use of topical corticosteroids and local application of mitomycin C. However, supportive evidence for their use in clinical practice from well-designed RCTs is lacking. Laboratory studies on topical rosiglitazone therapy, vitamin C prophylaxis, gene therapy, and stem cell therapy have shown promising results but have yet to be translated to clinical research.

CONCLUSION

There is a need for more robust randomized controlled trials to support treatments using topical corticosteroids and mitomycin C. Furthermore, their clinical efficacy and safety profile should be compared with new treatments that have shown promising results in the laboratory setting. Ultimately, the goal should be to personalize cornea scarring treatment according to the most effective treatment for the specific underlying pathology.

An Adrenalectomy Mouse Model Reflecting Clinical Features for Chronic Fatigue Syndrome

Chronic fatigue syndrome (CFS) is one of the most intractable diseases and is characterized by severe central fatigue that impairs even daily activity. To date, the pathophysiological mechanisms are uncertain and no therapies exist. Therefore, a proper animal model reflecting the clinical features of CFS is urgently required. We compared two CFS animal models most commonly used, by injection with lipopolysaccharide (LPS from Escherichia coli O111:B4) or polyinosinic: polycytidylic acid (poly I:C), along with bilateral adrenalectomy (ADX) as another possible model. Both LPS- and poly I:C-injected mice dominantly showed depressive behaviors, while ADX led to fatigue-like performances with high pain sensitivity. In brain tissues, LPS injection notably activated microglia and the 5-hydroxytryptamine (HT)_1A receptor in the prefrontal cortex and hippocampus. Poly I:C-injection also remarkably activated the 5-HT transporter and 5-HT_1A receptor with a reduction in serotonin levels in the brain. ADX particularly activated astrocytes and transforming growth factor beta (TGF-β) 1 in all brain regions. Our results revealed that LPS and poly I:C animal models approximate depressive disorder more closely than CFS. We suggest that ADX is a possible method for establishing a mouse model of CFS reflecting clinical features, especially in neuroendocrine system.

Phosphorylation of the glucocorticoid receptor alters SMAD signaling in vocal fold fibroblasts

OBJECTIVES/HYPOTHESIS

Direct glucocorticoid (GC) injection for vocal fold (VF) scarring has evolved as a therapeutic strategy, but the mechanisms underlying the antifibrotic effects remain unclear. GCs act via the glucocorticoid receptor (GR), which is phosphorylated at multiple serine residues in a hormone-dependent manner to affect bioactivity. We hypothesize that GCs regulate SMAD signaling via GR phosphorylation in vocal fold fibroblasts (VFFs).

STUDY DESIGN

In vitro.

METHODS

Human VFFs were treated with dexamethasone (DM; 10^-5 -10^-7 M) ± transforming growth factor (TGF)-β1 (10 ng/mL). RU486 (10^-6 M) was employed to isolate the regulatory effects of GR. Total GR, Ser²¹¹ , and Ser²⁰³ phosphorylation was examined via sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunocytochemistry. Quantitative polymerase chain reaction was employed to determine GR-mediated effects of DM on genes related to fibrosis.

RESULTS

Total GR and Ser²¹¹ phosphorylation was observed predominantly in the nucleus 1 hour after DM administration. DM decreased total GR expression, but Ser²⁰³ and Ser²¹¹ phosphorylation increased. RU486 limited the effects of DM. SMAD3 and SMAD7 mRNA expression significantly decreased 4 hours after DM administration (P < 0.05); this response was negated by RU486. COL1A1 remained unchanged, and ACTA2 significantly increased following 24 hours of DM treatment (P < 0.05).

CONCLUSION

DM regulated TGF-β1 signaling via altered SMAD3 and SMAD7 expression. This response was associated with altered GR phosphorylation. These findings provide insight into the mechanisms of steroidal effects on vocal fold repair; ultimately, we seek to enhance therapeutic strategies for these challenging patients.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:E187-E193, 2019.

Protective effect of dexamethasone on 5-FU-induced oral mucositis in hamsters

Oral mucositis (OM) is an important side effect of cancer treatment, characterized by ulcerative lesions in the mucosa of patients undergoing radiotherapy or chemotherapy, which has marked effects on patient quality of life and cancer therapy continuity. Considering that few protocols have demonstrated efficacy in preventing this side effect, the aim of this study was to examine the effect of dexamethasone (DEX) on OM induced by 5-fluorouracil (5-FU) in hamsters by studying signaling pathways. OM was induced in hamsters by 5-FU followed by mechanical trauma (MT) on day 4. On day 10, the animals were euthanized. The experimental groups included saline, MT, 5-FU, and DEX (0.25, 0.5, or 1 mg/kg). Macroscopic, histopathological, and immunohistochemical analyses as well as immunofluorescence experiments were performed on the oral mucosa of the animals. The oral mucosal samples were analyzed by enzyme-linked immunosorbent assays, and quantitative real-time polymerase chain reaction (qPCR). DEX (0.5 or 1 mg/kg) reduced inflammation and ulceration of the oral mucosa of hamsters. In addition, DEX (1 mg/kg) reduced the cytokine levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and macrophage migration inhibitory factor (MIF). DEX (1 mg/kg) also reduced the immunoexpression of cyclooxygenase (COX)-2, matrix metalloproteinase (MMP)-2, transforming growth factor (TGF)-β, MIF, Smad 2/3, Smad 2/3 phosphorylated and NFκB p65 in the jugal mucosa. Finally, DEX (1 mg/kg) increased interleukin-1 receptor-associated kinase 3 (IRAK-M), glucocorticoid-induced leucine zipper (GILZ), and mitogen-activated protein kinase (MKP1) gene expression and reduced NFκB p65 and serine threonine kinase (AKt) gene expression, relative to the 5-FU group. Thus, DEX improved OM induced by 5-FU in hamsters.

Transforming Growth Factor Beta is regulated by a Glucocorticoid-Dependent Mechanism in Denervation Mouse Bone

Bone growth and remodeling is inhibited by denervation in adults and children, resulting in alterations of linear growth and bone mass and increased risk for osteoporosis and pathologic fractures. Transforming growth factor beta (TGF-β) isoforms are a key group of growth factors that enhance bone formation. To explore the relation between denervation-induced reduction of bone formation and TGF-β gene expression, we measured mRNA levels of TGF-β in denervation mouse bone and found decreased mRNA levels of TGF-β1, TGF-β2 and TGF-β3. These changes were accompanied by diminishing weight loss, bone mineral density (BMD), trabecular thickness, trabecular separation and trabecular number of femur and lumbar, serum osteocalcin, total calcium, intact parathyroid hormone, and increased serum C telopeptide. Recombinant human TGF-β1 (rhTGF-β1) prevented denervation-induced reduction of BMD further supporting our hypothesis that denervation-induced reduction of bone formation is a result of inhibition of TGF-β gene expression. In addition, antiprogestins RU 38486 blunted the denervation-induced decrease in mRNA levels of TGF-β group, while dexamethasone (DEX) decreased TGF-β group mRNA levels in normal mice. Furthermore, the denervated-mice exhibited a threefold increase in plasma corticosterone. These results suggest that denervation-induced reduction of bone formation may be regulated by glucocorticoids via inhibition of TGF-β gene expression at least in part.

Glucocorticoid receptor expression on circulating leukocytes in healthy and asthmatic adolescents in response to exercise

BackgroundPoor aerobic fitness is associated with worsening of asthma symptoms, and fitness training may improve asthma control. The mechanism linking fitness with asthma is not known. We hypothesized that repeated bouts of exercise would lead to a downregulation of glucocorticoid receptor (GR) expression on circulating leukocytes, reflecting a reduced responsiveness to stress.MethodsIn a prospective exercise training intervention of healthy and asthmatic adolescents, GR expression in leukocytes was measured using flow cytometry in response to an acute exercise challenge before and after the exercise training intervention. Peripheral blood mononuclear cell (PBMC) gene expression of GR, GRβ, HSP70, TGFβ1, and TGFβ2 was determined using reverse-transcriptase PCR (RT-PCR).ResultsPeak VO₂ increased by 14.6±2.3%, indicating an effective training (P<0.01). There was a significant difference in GR expression among leukocyte subtypes, with highest expression in eosinophils. Following the exercise training intervention, there was a significant decrease in baseline GR expression (P<0.05) in leukocyte and monocyte subtypes in both healthy and asthmatic adolescents.ConclusionsThis is the first study in adolescents to show that exercise training reduces GR expression in circulating leukocytes. We speculate that exercise training downregulates the stress response in general, manifested by decreased GR expression, and may explain why improving fitness improves asthma health.

Effects of Acute Confinement Stress-induced Hypothalamic-Pituitary Adrenal Axis Activation and Concomitant Peripheral and Central Transforming Growth Factor-β1 Measures in Nonhuman Primates

Transforming growth factor-β1 (TGF-β1) is a multifunctional cytokine with anti-inflammatory, immunosuppressive, and neuroprotective properties. The hypothalamic-pituitary-adrenal axis and immune system exert bidirectional influences on each other, via cortisol and TGF-β1, but the exact nature of the interaction is not well characterized. The current study examined the effects, in bonnet macaques (Macaca radiata), of two consecutive acute confinement stress periods in an unfamiliar room while mildly restrained, first without and then with dexamethasone pretreatment (0.01 mg/kg intramuscular). Preceding the confinement studies, a non-stress control condition obtained contemporaneous levels of cortisol and TGF-β1 in both plasma and cerebrospinal fluid to match the confinement stress studies. Subjects were reared under either normative or variable foraging demand conditions. Since there were no rearing effects at baseline or for any of the conditions tested—either for cortisol or TGF-β—the study analyses were conducted on the combined rearing groups. The stress condition increased both plasma and cerebrospinal fluid cortisol levels whereas dexamethasone pretreatment decreased cortisol concentrations to below baseline levels despite stress. The stress condition decreased TGF-β1 concentrations only in cerebrospinal fluid but not in serum. Together, the data suggested that stress-induced reductions of a centrally active neuroprotective cytokine occur in the face of hypothalamic-pituitary-adrenal axis activation, potentially facilitating glucocortoid-induced neurotoxicity. Stress-induced reductions of neuroprotective cytokines prompt exploration of protective measures against glucocorticoid-induced neurotoxicity.

Glucocorticoids and erythropoietin in chronic lung disease of prematurity: Proliferative potential in lung fibroblast and epithelial cells exposed to tracheal aspirates

BACKGROUND

We investigated the effects of glucocorticoids, erythropoietin (EPO) and spironolactone (SPL) n human fetal lung fibroblasts and human alveolar epithelial cells exposed to tracheal aspirate fluid (TAF) from extremely premature infants with chronic lung disease (CLD), characterized by fibrosis and changes in the alveolar epithelium.

METHODS

Fibroblasts and epithelial cells (FHs 738Lu and A549, respectively) were treated with different concentrations of hydrocortisone (HDC), dexamethasone (DEX), betamethasone (BET), SPL, and EPO in the absence or presence of TAF from infants with CLD (gestational age, 25.3 ± 0.8 weeks; birthweight, 658 ± 77 g; postnatal age, 0-28 days) and assayed for proliferation.

RESULTS

Exposure to TAF resulted in a concentration-dependent proliferation of fibroblasts and epithelial cells. Proliferation of TAF-exposed fibroblasts was suppressed most significantly by 100 μmol/L DEX (21%, P = 0.046) and 300 mIU/mL EPO (18%, P = 0.02) and promoted most significantly by 0.4 μmol/L HDC (10%, P = 0.04). Epithelial proliferation was promoted by 4 μmol/L HDC (15%, P = 0.04), 10 μmol/L DEX (53%, P < 0.01), 0.2 μmol/L BET (56%, P < 0.01), and 300 mIU/mL EPO (35%, P < 0.01) in the presence of TAF. Treatment with glucocorticoids alone did not significantly affect fibroblast proliferation.

CONCLUSIONS

Glucocorticoids and EPO reduced fibroproliferation while promoting epithelial cell growth in vitro within certain dose ranges. Appropriate doses of glucocorticoids and EPO may be useful in the prevention and resolution of CLD in extremely premature infants.

The NR3C1 Glucocorticoid Receptor Gene Polymorphisms May Modulate the TGF-beta mRNA Expression in Asthma Patients

Glucocorticosteroids (GCs) are basic drugs in therapy of a number of diseases, including chronic diseases of the respiratory system. They are the most important anti-inflammatory drugs in the treatment of asthma. GCs after binding to the glucocorticoid receptor (GR) form the complex (transcription factor), which acts on promoter and regulatory parts of genes enhancing the expression of anti-inflammatory proteins and decreasing the proinflammatory protein synthesis, including numerous cytokines mediating inflammation in the course of asthma. Non-sensitivity or resistance to GCs favours an increase in the TGF-β expression. This cytokine plays a central role in asthma inducing fibroblast differentiation and extracellular matrix synthesis. TGF-β isoforms, 1, 2 and 3, are located on chromosome 19q13, 1q41 and 14q24, respectively. GCs reduce TGF-β 1 and TGF-β 2 production and significantly decrease the expression of upregulated TGF-β 1 and TGF-β 2 mRNA induced by exogenous TGF-β. In asthma, TGF-β may play a role in the development of the peribronchiolar and subepithelial fibrosis, which contributes to a significant clinical exacerbation of asthma. Therefore, it is possible that NR3C1 glucocorticoid receptor gene polymorphisms could exert varied effects on the TGF-β mRNA expression and fibrotic process in lungs of asthmatic patients. The aim of the study was to evaluate the impact of polymorphic forms (Tth111I, BclI, ER22/23EK, N363S) of the NR3C1 gene on the level of the TGF-β 1 mRNA expression. A total of 173 patients with asthma and 163 healthy volunteers participated in the study. Genotyping of Tth111I, BclI, ER22/23EK, and N363S polymorphisms of the NR3C1 gene was performed by using PCR-HRM and PCR-RFLP techniques. TGF-β mRNA was assessed by real time RT-PCR. Tth111I SNP significantly (p = 0.0115) correlated with the TGF-β 1 mRNA expression level. The significance of AA and GG genotypes of Tth111I SNP in increasing and decreasing the level of the TGF-β 1 mRNA expression was demonstrated. Both BclI SNP and ER22/23EK SNP did not affect the expression level of the cytokine analysed. The N363S SNP AA genotype of NR3C1 gene statistically significantly influenced the increase in the level of the TGF-β 1 mRNA expression. Thus, SNPs of NR3C1 gene play an important regulatory function in the bronchi of patients suffering from asthma. In the case of the occurrence of Tth111I and N363S polymorphic forms of the gene studied, a reduced ability of GCs to inhibit the TGF-β 1 expression can be observed.

Inhibition of TGFβ signaling decreases osteogenic differentiation of fibrodysplasia ossificans progressiva fibroblasts in a novel in vitro model of the disease

Fibrodysplasia ossificans progressiva is a rare genetic disorder characterized by progressive heterotopic ossification. FOP patients develop soft tissue lumps as a result of inflammation-induced flare-ups which leads to the irreversible replacement of skeletal muscle tissue with bone tissue. Classical FOP patients possess a mutation (c.617G>A; R206H) in the ACVR1-encoding gene which leads to dysregulated BMP signaling. Nonetheless, not all FOP patients with this mutation exhibit equal severity in symptom presentation or disease progression which indicates a strong contribution by environmental factors. Given the pro-inflammatory role of TGFβ, we studied the role of TGFβ in the progression of osteogenic differentiation in primary dermal fibroblasts from five classical FOP patients based on a novel method of platelet lysate-based osteogenic transdifferentiation. During the course of transdifferentiation the osteogenic properties of the cells were evaluated by the mRNA expression of Sp7/Osterix, Runx2, Alp, OC and the presence of mineralization. During transdifferentiation the expression of osteoblast markers Runx2 (p<0.05) and Alp were higher in patient cells compared to healthy controls. All cell lines exhibited increase in mineralisation. FOP fibroblasts also expressed higher baseline Sp7/Osterix levels (p<0.05) confirming their higher osteogenic potential. The pharmacological inhibition of TGFβ signaling during osteogenic transdifferentiation resulted in the attenuation of osteogenic transdifferentiation in all cell lines as shown by the decrease in the expression of Runx2 (p<0.05), Alp and mineralization. We suggest that blocking of TGFβ signaling can decrease the osteogenic transdifferentiation of FOP fibroblasts.

Antenatal glucocorticoids counteract LPS changes in TGF-β pathway and caveolin-1 in ovine fetal lung

Inflammation and antenatal glucocorticoids, the latter given to mothers at risk for preterm birth, affect lung development and may contribute to the development of bronchopulmonary dysplasia (BPD). The effects of the combined exposures on inflammation and antenatal glucocorticoids on transforming growth factor (TGF)-β signaling are unknown. TGF-β and its downstream mediators are implicated in the etiology of BPD. Therefore, we asked whether glucocorticoids altered intra-amniotic lipopolysaccharide (LPS) effects on TGF-β expression, its signaling molecule phosphorylated sma and mothers against decapentaplegic homolog 2 (pSmad2), and the downstream mediators connective tissue growth factor (CTGF) and caveolin-1 (Cav-1). Ovine singleton fetuses were randomized to receive either an intra-amniotic injection of LPS and/or maternal betamethasone (BTM) intramuscularly 7 and/or 14 days before delivery at 120 days gestational age (GA; term = 150 days GA). Saline was used for controls. Protein levels of TGF-β1 and -β2 were measured by ELISA. Smad2 phosphorylation was assessed by immunohistochemistry and Western blot. CTGF and Cav-1 mRNA and protein levels were determined by RT-PCR and Western blot. Free TGF-β1 and -β2 and total TGF-β1 levels were unchanged after LPS and/or BTM exposure, although total TGF-β2 increased in animals exposed to BTM 7 days before LPS. pSmad2 immunostaining increased 7 days after LPS exposure although pSmad2 protein expression did not increase. Similarly, CTGF mRNA and protein levels increased 7 days after LPS exposure as Cav-1 mRNA and protein levels decreased. BTM exposure before LPS prevented CTGF induction and Cav-1 downregulation. This study demonstrated that the intrauterine inflammation-induced TGF-β signaling can be inhibited by antenatal glucocorticoids in fetal lungs.

Transforming growth factor-β and atherosclerosis: interwoven atherogenic and atheroprotective aspects

Age-related progression of cardiovascular disease is by far the largest health problem in the US and involves vascular damage, progressive vascular fibrosis and the accumulation of lipid-rich atherosclerotic lesions. Advanced lesions can restrict flow to key organs and can trigger occlusive thrombosis resulting in a stroke or myocardial infarction. Transforming growth factor-beta (TGF-β) is a major orchestrator of the fibroproliferative response to tissue damage. In the early stages of repair, TGF-β is released from platelets and activated from matrix reservoirs; it then stimulates the chemotaxis of repair cells, modulates immunity and inflammation and induces matrix production. At later stages, it negatively regulates fibrosis through its strong antiproliferative and apoptotic effects on fibrotic cells. In advanced lesions, TGF-β might be important in arterial calcification, commonly referred to as "hardening of the arteries". Because TGF-β can signal through multiple pathways, namely the SMADs, a MAPK pathway and the Rho/ROCK pathways, selective defects in TGF-β signaling can disrupt otherwise coordinated pathways of tissue regeneration. TGF-β is known to control cell proliferation, cell migration, matrix synthesis, wound contraction, calcification and the immune response, all being major components of the atherosclerotic process. However, many of the effects of TGF-β are essential to normal tissue repair and thus, TGF-β is often thought to be "atheroprotective". The present review attempts to parse systematically the known effects of TGF-β on both the major risk factors for atherosclerosis and to isolate the role of TGF-β in the many component pathways involved in atherogenesis.

Fra-2 mediates oxygen-sensitive induction of transforming growth factor beta in cardiac fibroblasts

AIMS

In the ischaemia-reperfused heart, transforming growth factor beta (TGFbeta) proteins trigger the differentiation of cardiac fibroblasts (CFs) contributing to fibrosis. Reoxygenation of the heart, in addition to being a trigger for reperfusion injury, induces tissue remodelling by hyperoxia-sensitive signalling processes involving TGFbeta. Here, we sought to characterize the molecular mechanisms responsible for the O(2)-sensitive transcriptional induction of TGFbeta in murine CF and to test the significance of such findings in the infarcted myocardium in vivo using laser capture microdissection.

METHODS AND RESULTS

All three isoforms of TGFbeta were induced in the CF-rich peri-infarct tissue as well as in CF exposed to hyperoxic challenge. Reporter studies demonstrated that TGFbeta transcription is hyperoxia inducible. Deletion of any one or both of the activating protein-1 (AP-1) binding sites in the TGFbeta reporter construct resulted in loss of O(2) sensitivity, demonstrating that AP-1 confers O(2) sensitivity to TGFbeta transcription. Fos-related AP-1 transcription factor (Fra-2) and Ask-1 (apoptosis signal-regulating kinase-1) were identified as key mediators of AP-1-dependent O(2)-sensitive TGFbeta transcription. Knockdown of Fra-2 significantly blunted O(2)-induced expression of TGFbeta1 as well as TGFbeta3 in CF. Knockdown of Ask-1 blunted hyperoxia-induced Fra-2 gene expression and nuclear localization in CF. Collectively, these observations point towards a central role of Ask-1 and Fra-2 in O(2)-inducible AP-1 activation and induction of TGFbeta.

CONCLUSION

Taken together with the observation that Fra-2-regulated genes are implicated in fibrosis, identification of Fra-2 as an O(2)-sensitive transcriptional regulator of inducible TGFbeta expression positions Fra-2 as an important player in reoxygenation-induced fibrosis.

The Etiology of Steroid Cataract

Steroid-induced posterior subcapsular cataracts (PSCs) exhibit three main distinctive characteristics: (i) association only with steroids possessing glucocorticoid activity, (ii) involvement of aberrant migrating lens epithelial cells, and (iii) a central posterior location. The first characteristic suggests a key role for glucocorticoid receptor activation and subsequent changes to the transcription of specific genes. Glucocorticoid receptor activation is associated in many cell types with proliferation, suppressed differentiation, a reduced susceptibility to apoptosis, altered transmembrane transport, and enhancement of reactive oxygen species activity. Glucocorticoids may be capable of inducing changes to the transcription of genes in lens epithelial cells that are related to many of these cellular processes. This review examines the various mechanisms that have been proposed to account for the development of PSC in the context of recent DNA array studies. Additionally, given that the glucocorticoid receptor can also engender wide-ranging indirect activities, glucocorticoids could also indirectly affect the lens through the responses of other cells within the ocular compartment and/or through effects on cells at more remote locations. These indirect mechanisms, which, for example, could be mediated through alterations to the intraocular levels of growth factors that normally orchestrate lens development and maintain lens homeostasis, are also discussed. Although the mechanism of steroid cataract induction remains unknown, glucocorticoid-induced gene transcription events in lens epithelial cells, and also other intraocular or systemic cells, likely interact to generate steroid cataracts. Finally, although evidence for glucocorticoid-protein adduct formation in the lens is inconclusive, the generation of such adducts cannot yet be discounted as a contributing factor and must necessarily be retained in discussions of the etiology of steroid cataract.

Regulation of clusterin expression in mammary epithelial cells

Mammary epithelial cells undergo changes in growth, invasion, differentiation, and dedifferentiation throughout much of adult hood, and most strikingly during pregnancy, lactation, and involution. Clusterin is a multifunctional glycoprotein that is involved in the differentiation and morphogenesis of epithelia, and that is important in the regulation of postnatal mammary gland development. However, the mechanisms that regulate clusterin expression are still poorly understood. Here, we show that clusterin is up-regulated twice during mouse mammary gland development, a first time at the end of pregnancy and a second time at the beginning of the involution. These points of clusterin up-regulation coincide with the dramatic phenotypic and functional changes occurring in the mammary gland. Using cell culture conditions that resemble the regulatory microenvironment in vivo, we determined that the factors responsible for the first up-regulation of clusterin levels can include the extracellular matrix component, laminin, and the lactogenic hormones, prolactin and hydrocortisone. On the other hand, the second and most dramatic up-regulation of clusterin can be due to the potent induction by TGF-beta1, and this up-regulation by TGF-beta1 is dependent on beta1 integrin ligand-binding activity. Moreover, the level of expression of beta-casein, a marker of mammary epithelial cell differentiation, was decreased upon treatment of cells with clusterin siRNA. Overall, these findings reveal several novel pathways for the regulation of clusterin expression during mammary gland development, and suggest that clusterin is a morphogenic factor that plays a key role during differentiation.

The αvβ6 integrin plays a role in compromised epidermal wound healing

The alphavbeta6 integrin is an exclusively epithelial integrin that is highly expressed during fetal development. In adult tissue, alphavbeta6 integrin is expressed during inflammation, carcinogenesis, and in wound healing. We previously reported that alphavbeta6 integrin is highly expressed in poorly healing human wounds and its over-expression is associated with chronic wounds in a mouse model. The objective of this study was to investigate the role of alphavbeta6 integrin in compromised wound healing induced by hydrocortisone treatment or aging by using young and old mice deficient in or overexpressing the beta6 integrin subunit in the epidermis. Untreated aged beta6 integrin-deficient (beta6-/-) animals showed a significant delay in wound healing when compared to their age-matched controls or younger beta6-/- mice. The most significant delay was observed at the stages where granulation tissue deposition was occurring. Hydrocortisone treatment significantly delayed wound healing in wild-type and beta6 integrin-deficient mice in comparison with the untreated controls. However, hydrocortisone treatment in beta6 integrin overexpressing animals did not cause a significant delay in wound healing. The results of this study suggest that alphavbeta6 integrin plays an important role in wound healing in animals compromised by either age or stress mimicked by hydrocortisone.

Effects of TGF-β and glucocorticoids on map kinase phosphorylation, IL-6/IL-11 secretion and cell proliferation in primary cultures of human lung fibroblasts

Transforming growth factor-beta1 (TGF-beta1) is crucially involved in the fibrotic events characterizing interstitial lung diseases (ILDs), as well as in the airway remodeling process typical of asthma. Within such a context, the aim of our study was to investigate, in primary cultures of normal and fibrotic human lung fibroblasts (HLFs), the effects of TGF-beta1 on mitogen-activated protein kinase (MAPK) phosphorylation, cell proliferation, and production of interleukins 6 (IL-6) and 11 (IL-11), in the presence or absence of a pretreatment with budesonide (BUD). MAPK phosphorylation was detected by Western blotting, cell viability and proliferation were evaluated using Trypan blue staining and [(3)H]-thymidine incorporation assay, respectively, and the release of IL-6 and IL-11 into cell culture supernatants was assessed by ELISA. TGF-beta1 (10 ng/ml) significantly stimulated MAPK phosphorylation (P < 0.01), and also enhanced cell proliferation as well as the secretion of both IL-6 and IL-11, which reached the highest increases at the 72nd h of cell exposure to this growth factor. All such effects were prevented by BUD (10(-8) M) and, with the exception of IL-6 release, also by a mixture of MAPK inhibitors. Therefore, our findings suggest that the fibrotic action exerted by TGF-beta1 in the lung is mediated at least in part by MAPK activation and by an increased synthesis of the profibrogenic cytokines IL-6 and IL-11; all these effects appear to be prevented by corticosteroids via inhibition of MAPK phosphorylation.

Fatal pulmonary fibrosis associated with BCNU: the relative role of platelet-derived growth factor-B, insulin-like growth factor I, transforming growth factor-β1 and cyclooxygenase-2

Pulmonary fibrosis is a severe complication associated with bis-chloronitrosourea (BCNU) therapy. However, the pathogenetic mechanism has never been well investigated. We report here a 26-year-old female with diffuse large B-cell lymphoma who died of severe pulmonary fibrosis 81 days after the administration of high-dose BCNU (600 mg/m2). Thoracoscopic wedge resection of left upper lung performed 10 days before patient's death showed severe pulmonary fibrosis with prominent hyperplasia of alveolar macrophages and type II pneumocytes. We further used immunohistochemistry (IHC) to examine the relative role of platelet-derived growth factor-B (PDGF-B), insulin-like growth factor I (IGF-I), transforming growth factor-beta1 (TGF-beta1) and cyclooxygenase-2 (COX-2) in the pathogenesis of BCNU-related pulmonary fibrosis. Strong expressions of PDGF-B and IGF-1 on alveolar macrophages and type II pneumocytes were clearly demonstrated, but in contrast, the expressions of TGF-beta1 and COX-2 were almost undetectable. In conclusion, pulmonary fibrosis can develop early and progress rapidly after the administration of high-dose BCNU. The markedly increased expression of fibrogenic factors PDGF-B and IGF-1 on hyperplastic alveolar macrophages and hyperplastic type II pneumocytes may play an important role in the fibrogenesis of this disease. These novel findings may offer specific therapeutic targets in the treatment of BCNU-associated pulmonary fibrosis.