Concentration Effects of Methylprednisolone in Human Vocal Fold Fibroblast-Macrophage Co-Culture
OBJECTIVE:The diversity of glucocorticoid (GC) properties may underlie variability of clinical efficacy for vocal fold (VF) disease. Optimized therapeutic approaches must account for tissue complexity as well as interactions between cell types. We previously reported that reduced GC concentrations inhibited inflammation without eliciting fibrosis in mono-cultured VF fibroblasts and macrophages. These data suggested that a refined approach to GC concentration may improve outcomes. In the current study, co-culture of VF fibroblasts and macrophages was employed to investigate the effects of different concentrations of methylprednisolone on fibrotic and inflammatory response genes in VF fibroblasts to optimize management paradigms. STUDY DESIGN/METHODS:In vitro. METHODS:THP-1 monocyte-derived macrophages were stimulated with interferon-γ (IFN-γ), lipopolysaccharide (LPS), or transforming growth factor-β (TGF-β) to induce inflammatory (M(IFN/LPS)) and fibrotic (M(TGF)) phenotypes. Macrophages were then co-cultured with a human VF fibroblast cell line using a 0.4 μm pore membrane with or without 0.1-3000 nM methylprednisolone. Inflammatory (CXCL10, TNF, and PTGS2) and fibrotic (ACTA2, CCN2, and COL1A1) gene expression was quantified in fibroblasts. RESULTS:Incubating VF fibroblasts with M(IFN/LPS) macrophages increased expression of TNF and PTGS2, and this effect was inhibited by methylprednisolone. Incubation of VF fibroblasts with M(TGF) macrophages increased expression of ACTA2, CCN2, and COL1A1, and this effect was enhanced by methylprednisolone. The concentration of methylprednisolone required to downregulate inflammatory genes (TNF and PTGS2) was lower than that to upregulate fibrotic genes (ACTA2, CCN2, and COL1A1). CONCLUSION/CONCLUSIONS:Reduced concentration of methylprednisolone effectively suppressed inflammatory genes without enhancing fibrotic genes, suggesting that a refined approach to GC concentration may improve clinical outcomes. LEVEL OF EVIDENCE/METHODS:N/A Laryngoscope, 2023.
MED19 encodes two unique protein isoforms that confer prostate cancer growth under low androgen through distinct gene expression programs
MED19, a component of the mediator complex and a co-regulator of the androgen receptor (AR), is pivotal in prostate cancer cell proliferation. MED19 has two isoforms: a full-length "canonical" and a shorter "alternative" variant. Specific antibodies were developed to investigate these isoforms. Both exhibit similar expression in normal prostate development and adult prostate tissue, but the canonical isoform is elevated in prostate adenocarcinomas. Overexpression of canonical MED19 in LNCaP cells promotes growth under conditions of androgen deprivation in vitro and in vivo, mirroring earlier findings with alternative MED19-overexpressing LNCaP cells. Interestingly, alternative MED19 cells displayed strong colony formation in clonogenic assays under conditions of androgen deprivation, while canonical MED19 cells did not, suggesting distinct functional roles. These isoforms also modulated gene expression differently. Canonical MED19 triggered genes related to extracellular matrix remodeling while suppressing those involved in androgen-inactivating glucuronidation. In contrast, alternative MED19 elevated genes tied to cell movement and reduced those associated with cell adhesion and differentiation. The ratio of MED19 isoform expression in prostate cancers shifts with the disease stage. Early-stage cancers exhibit higher canonical MED19 expression than alternative MED19, consistent with canonical MED19's ability to promote cell proliferation under androgen deprivation. Conversely, alternative MED19 levels were higher in later-stage metastatic prostate cancer than in canonical MED19, reflecting alternative MED19's capability to enhance cell migration and autonomous cell growth. Our findings suggest that MED19 isoforms play unique roles in prostate cancer progression and highlights MED19 as a potential therapeutic target for both early and late-stage prostate cancer.
Glucocorticoid Dose Dependency on Gene Expression in Vocal Fold Fibroblasts and Macrophages
OBJECTIVE:Glucocorticoids (GCs) modulate multiple cellular activities including inflammatory and fibrotic responses. Outcomes of GC treatment for laryngeal disease vary, affording opportunity to optimize treatment. In the current study, three clinically employed GCs were evaluated to identify optimal in vitro concentrations at which GCs mediate favorable anti-inflammatory and fibrotic effects in multiple cell types. We hypothesize a therapeutic window will emerge as a foundation for optimized therapeutic strategies for patients with laryngeal disease. STUDY DESIGN/METHODS:In vitro. METHODS:to alter inflammatory and fibrotic gene expression was calculated. RESULTS:to downregulate other genes. CONCLUSION/CONCLUSIONS:Lower concentrations of GCs repressed inflammatory gene expression and only moderately induced genes involved in fibrosis. These data warrant consideration as a foundation for optimized clinical care paradigms to reduce inflammation and mitigate fibrosis. LEVEL OF EVIDENCE/METHODS:NA Laryngoscope, 133:1169-1175, 2023.
Dose-Dependent Glucocorticoid Regulation of Transcription Factors in Vocal Fold Fibroblasts and Macrophages
Objective: Variable outcomes of glucocorticoid (GC) therapy for laryngeal disease are putatively due to diverse interactions of the GC receptor (GR) with cell signaling pathways, limited consideration regarding concentration-dependent effects, and inconsistent selection of GCs. In the current study, we evaluated the concentration-dependent effects of three frequently administered GCs on transcription factors with an emphasis on the phosphorylation of GR at Ser203 and Ser211 regulating the nuclear translocation of GR. This study provides foundational data regarding the diverse functions of GCs to optimize therapeutic approaches. Study design: In vitro. Methods: Human vocal fold fibroblasts and THP1-derived macrophages were treated with different concentrations of dexamethasone, methylprednisolone, and triamcinolone in combination with IFN-Î³, TNF-Î±, or IL4. Phosphorylated STAT1, NF-ÎºB family molecules, and phosphorylated STAT6 were analyzed by Western blotting. Ser211-phosphorylated GR (S211-pGR) levels relative to GAPDH and Ser203-phosphorylated GR (S203-pGR) were also analyzed. Results: GCs differentially altered phosphorylated STAT1 and NF-ÎºB family molecules in different cell types under IFN-Î³ and TNF-Î± stimuli. GCs did not alter phosphorylated STAT6 in IL4-treated macrophages. The three GCs were nearly equivalent. A lower concentration of dexamethasone increased S211-pGR/GAPDH ratios relative to increased S211-pGR/S203-pGR ratios regardless of cell type and treatment. Conclusion: The three GCs employed in two cell lines had nearly equivalent effects on transcription factor regulation. Relatively high levels of Ser203-phosphorylation at low GC concentrations may be related to concentration-dependent differential effects of GCs in the two cell lines. Level of Evidence: NA Laryngoscope, 2023.
Loss of PRMT2 in myeloid cells in normoglycemic mice phenocopies impaired regression of atherosclerosis in diabetic mice
The regression, or resolution, of inflammation in atherosclerotic plaques is impaired in diabetes. However, the factors mediating this effect remain incomplete. We identified protein arginine methyltransferase 2 (PRMT2) as a protein whose expression in macrophages is reduced in hyperglycemia and diabetes. PRMT2 catalyzes arginine methylation to target proteins to modulate gene expression. Because PRMT2 expression is reduced in cells in hyperglycemia, we wanted to determine whether PRMT2 plays a causal role in the impairment of atherosclerosis regression in diabetes. We, therefore, examined the consequence of deleting PRMT2 in myeloid cells during the regression of atherosclerosis in normal and diabetic mice. Remarkably, we found significant impairment of atherosclerosis regression under normoglycemic conditions in mice lacking PRMT2 (Prmt2-/-) in myeloid cells that mimic the decrease in regression of atherosclerosis in WT mice under diabetic conditions. This was associated with increased plaque macrophage retention, as well as increased apoptosis and necrosis. PRMT2-deficient plaque CD68+ cells under normoglycemic conditions showed increased expression of genes involved in cytokine signaling and inflammation compared to WT cells. Consistently, Prmt2-/- bone marrow-derived macrophages (BMDMs) showed an increased response of proinflammatory genes to LPS and a decreased response of inflammation resolving genes to IL-4. This increased response to LPS in Prmt2-/- BMDMs occurs via enhanced NF-kappa B activity. Thus, the loss of PRMT2 is causally linked to impaired atherosclerosis regression via a heightened inflammatory response in macrophages. That PRMT2 expression was lower in myeloid cells in plaques from human subjects with diabetes supports the relevance of our findings to human atherosclerosis.
Loss of glucocorticoid receptor phosphorylation contributes to cognitive and neurocentric damages of the amyloid-Î² pathway
Aberrant cortisol and activation of the glucocorticoid receptor (GR) play an essential role in age-related progression of Alzheimer's disease (AD). However, the GR pathways required for influencing the pathobiology of AD dementia remain unknown. To address this, we studied an early phase of AD-like progression in the well-established APP/PS1 mouse model combined with targeted mutations in the BDNF-dependent GR phosphorylation sites (serines 134/267) using molecular, behavioral and neuroimaging approaches. We found that disrupting GR phosphorylation (S134A/S267A) in mice exacerbated the deleterious effects of the APP/PS1 genotype on mortality, neuroplasticity and cognition, without affecting either amyloid-Î² deposition or vascular pathology. The dynamics, maturation and retention of task-induced new dendritic spines of cortical excitatory neurons required GR phosphorylation at the BDNF-dependent sites that amyloid-Î² compromised. Parallel studies in postmortem human prefrontal cortex revealed AD subjects had downregulated BDNF signaling and concomitant upregulated cortisol pathway activation, which correlated with cognitive decline. These results provide key evidence that the loss of neurotrophin-mediated GR phosphorylation pathway promotes the detrimental effects of the brain cortisol response that contributes to the onset and/or progression of AD dementia. These findings have important translational implications as they provide a novel approach to treating AD dementia by identifying drugs that increase GR phosphorylation selectively at the neurotrophic sites to improve memory and cognition.
Transcriptional regulation of Acsl1 by CHREBP and NF-kappa B in macrophages during hyperglycemia and inflammation
Acyl-CoA synthetase 1 (ACSL1) is an enzyme that converts fatty acids to acyl-CoA-derivatives for lipid catabolism and lipid synthesis in general and can provide substrates for the production of mediators of inflammation in monocytes and macrophages. Acsl1 expression is increased by hyperglycemia and inflammatory stimuli in monocytes and macrophages, and promotes the pro-atherosclerotic effects of diabetes in mice. Yet, surprisingly little is known about the mechanisms underlying Acsl1 transcriptional regulation. Here we demonstrate that the glucose-sensing transcription factor, Carbohydrate Response Element Binding Protein (CHREBP), is a regulator of the expression of Acsl1 mRNA by high glucose in mouse bone marrow-derived macrophages (BMDMs). In addition, we show that inflammatory stimulation of BMDMs with lipopolysaccharide (LPS) increases Acsl1 mRNA via the transcription factor, NF-kappa B. LPS treatment also increases ACSL1 protein abundance and localization to membranes where it can exert its activity. Using an Acsl1 reporter gene containing the promoter and an upstream regulatory region, which has multiple conserved CHREBP and NF-kappa B (p65/RELA) binding sites, we found increased Acsl1 promoter activity upon CHREBP and p65/RELA expression. We also show that CHREBP and p65/RELA occupy the Acsl1 promoter in BMDMs. In primary human monocytes cultured in high glucose versus normal glucose, ACSL1 mRNA expression was elevated by high glucose and further enhanced by LPS treatment. Our findings demonstrate that CHREBP and NF-kappa B control Acsl1 expression under hyperglycemic and inflammatory conditions.
PIM1 phosphorylation of the androgen receptor and 14-3-3 Î¶ regulates gene transcription in prostate cancer
PIM1 is a serine/threonine kinase over-expressed in prostate cancer. We have previously shown that PIM1 phosphorylates the androgen receptor (AR), the primary therapeutic target in prostate cancer, at serine 213 (pS213), which alters expression of select AR target genes. Therefore, we sought to investigate the mechanism whereby PIM1 phosphorylation of AR alters its transcriptional activity. We previously identified the AR co-activator, 14-3-3 Î¶, as an endogenous PIM1 substrate in LNCaP cells. Here, we show that PIM1 phosphorylation of AR and 14-3-3 Î¶ coordinates their interaction, and that they extensively occupy the same sites on chromatin in an AR-dependent manner. Their occupancy at a number of genes involved in cell migration and invasion results in a PIM1-dependent increase in the expression of these genes. We also use rapid immunoprecipitation and mass spectrometry of endogenous proteins on chromatin (RIME), to find that select AR co-regulators, such as hnRNPK and TRIM28, interact with both AR and 14-3-3 Î¶ in PIM1 over-expressing cells. We conclude that PIM1 phosphorylation of AR and 14-3-3 Î¶ coordinates their interaction, which in turn recruits additional co-regulatory proteins to alter AR transcriptional activity.
Glucocorticoids activate Yes-associated protein in human vocal fold fibroblasts
Fibrosis of the vocal folds poses a substantive clinical challenge potentially underlying the rapid proliferation of direct steroid injections into the upper airway. The variable clinical response to glucocorticoids (GCs) in the vocal folds is likely related to diversity inherent to GCs and both patient-specific, and upstream, cell-specific responses to GCs. Broadly, we hypothesize the disparity in clinical outcomes are due to undesirable effects of GCs on resident fibroblasts. Transcriptome analysis identified significant GC-mediated modulation of Hippo signaling, a known regulator of fibrotic gene expression. Subsequent analysis confirmed GC-mediated YAP activation, a transcriptional co-factor in the Hippo signaling pathway. YAP inhibition attenuated ACTA2 expression in GC-treated human vocal fold fibroblasts. Nuclear localization and phosphorylation at Ser211, however, was not affected by YAP inhibition, suggesting nuclear translocation of YAP is indirectly driven by GR. RNA-seq analysis confirmed the influence of GCs on Wnt signaling, and canonical Wnt signaling target genes were upregulated by GCs. These data implicate YAP and its downstream targets as putative mediators of a pro-fibrotic response to GCs. Therapeutic YAP inhibition may ultimately be clinically relevant and warrants further consideration.
Inhibiting LXRÎ± phosphorylation in hematopoietic cells reduces inflammation and attenuates atherosclerosis and obesity in mice
Atherosclerosis and obesity share pathological features including inflammation mediated by innate and adaptive immune cells. LXRÎ± plays a central role in the transcription of inflammatory and metabolic genes. LXRÎ± is modulated by phosphorylation at serine 196 (LXRÎ± pS196), however, the consequences of LXRÎ± pS196 in hematopoietic cell precursors in atherosclerosis and obesity have not been investigated. To assess the importance of LXRÎ± phosphorylation, bone marrow from LXRÎ±Â WT and S196A mice was transplanted into Ldlr-/- mice, which were fed a western diet prior to evaluation of atherosclerosis and obesity. Plaques from S196A mice showed reduced inflammatory monocyte recruitment, lipid accumulation, and macrophage proliferation. Expression profiling of CD68+ and T cells from S196A mouse plaques revealed downregulation of pro-inflammatory genes and in the case of CD68+ upregulation of mitochondrial genes characteristic of anti-inflammatory macrophages. Furthermore, S196A mice had lower body weight and less visceral adipose tissue; this was associated with transcriptional reprograming of the adipose tissue macrophages and T cells, and resolution of inflammation resulting in less fat accumulation within adipocytes. Thus, reducing LXRÎ± pS196 in hematopoietic cells attenuates atherosclerosis and obesity by reprogramming the transcriptional activity of LXRÎ± in macrophages and T cells to promote an anti-inflammatory phenotype.