Bromodomain Inhibitor JQ1 Modulates Collagen Processing and Ameliorates Bleomycin Induced Dermal Fibrosis in Mice

Background/Purpose: Systemic sclerosis (SSc) is a complex pro-inflammatory scarring disease, characterised by elevated deposition of extracellular matrix (ECM) proteins, in particular collagen type I. The disease is heterogeneous affecting both the skin and visceral organs including kidney, lung and heart. The SSc fibroblast is a key cell which promotes a pro-inflammatory and fibrotic microenvironment that can lead to the loss of normal tissue architecture and organ function. The mechanisms that contribute to the formation and persistence of the SSc dermal fibroblast remain unclear. We have previously shown the epigenetic bromodomain and extra-terminal domain-containing proteins (Brd) which bind to acetylated histone residues, play a significant role in pulmonary fibrosis. Here we seek to explore the contribution of Brd proteins in the development of dermal fibrosis using a specific inhibitor of Brd proteins (Brd 2, 3, 4 and T), JQ1. Methods: We investigated the dose-response of JQ1 on SSc and healthy control (HC) donor (n≥3) dermal fibroblasts. We assessed the effects on collagen deposition and processing using the Scar-in-a-Jar in vitrofibrosis assay, by western blot and immuno-florescence microscopy for collagen type I (n=4). To determine the effect of JQ1 in a pre-clinical model of skin fibrosis, female C57BL/6 mice were given three weekly subcutaneous injections of 100µl sterile saline (n≥6) or 0.1U/ml bleomycin (n≥6) for 14 days and treated with 12mg/kg/day JQ1 (n≥6) or vehicle (n≥6). After 14 days histological analysis for fibrogenic proteins and ECM was performed on skin, and pro-inflammatory chemokines in sera assessed by ELISA. Results: IL-6 and MCP-1 secretion by SSc and HC donor fibroblasts was significantly (P<0.05) inhibited in a dose dependent manner by JQ1. Consistent with this JQ1 attenuated SSc collagen deposition and processing (P˂0.05). Assessment of JQ1 in a pre-clinical model of dermal fibrosis demonstrated a markedly attenuation of dermal thickening in vivo(P˂0.05). Consistent with this we observed significant reduction in fibrogenic markers including αSMA, and collagen expression in the skin (P˂0.05). Furthermore secretion of the inflammatory marker, IL-6 was significantly attenuated (P˂0.05). Conclusion: We have assessed the functional effects of the Brd inhibitor, JQ1, on SSc dermal fibroblasts and the development of dermal fibrosis in a pre-clinical model of dermal fibrosis. We demonstrate that JQ1 markedly attenuated the excessive deposition and processing of collagen type I by SSc fibroblasts. In keeping with Brd proteins playing a pivotal role in the development and progression of dermal fibrosis, JQ1 significantly inhibited ECM deposition in vivo. Our data suggests a key role for Brd proteins in the persistence of the SSc dermal fibroblast phenotype

Bromodomain Inhibitor JQ1 Modulates Collagen Processing and Ameliorates Bleomycin Induced Dermal Fibrosis in Mice

Background/Purpose: Systemic sclerosis (SSc) is a complex pro-inflammatory scarring disease, characterised by elevated deposition of extracellular matrix (ECM) proteins, in particular collagen type I. The disease is heterogeneous affecting both the skin and visceral organs including kidney, lung and heart. The SSc fibroblast is a key cell which promotes a pro-inflammatory and fibrotic microenvironment that can lead to the loss of normal tissue architecture and organ function. The mechanisms that contribute to the formation and persistence of the SSc dermal fibroblast remain unclear. We have previously shown the epigenetic bromodomain and extra-terminal domain-containing proteins (Brd) which bind to acetylated histone residues, play a significant role in pulmonary fibrosis. Here we seek to explore the contribution of Brd proteins in the development of dermal fibrosis using a specific inhibitor of Brd proteins (Brd 2, 3, 4 and T), JQ1. Methods: We investigated the dose-response of JQ1 on SSc and healthy control (HC) donor (n≥3) dermal fibroblasts. We assessed the effects on collagen deposition and processing using the Scar-in-a-Jar in vitrofibrosis assay, by western blot and immuno-florescence microscopy for collagen type I (n=4). To determine the effect of JQ1 in a pre-clinical model of skin fibrosis, female C57BL/6 mice were given three weekly subcutaneous injections of 100µl sterile saline (n≥6) or 0.1U/ml bleomycin (n≥6) for 14 days and treated with 12mg/kg/day JQ1 (n≥6) or vehicle (n≥6). After 14 days histological analysis for fibrogenic proteins and ECM was performed on skin, and pro-inflammatory chemokines in sera assessed by ELISA. Results: IL-6 and MCP-1 secretion by SSc and HC donor fibroblasts was significantly (P<0.05) inhibited in a dose dependent manner by JQ1. Consistent with this JQ1 attenuated SSc collagen deposition and processing (P˂0.05). Assessment of JQ1 in a pre-clinical model of dermal fibrosis demonstrated a markedly attenuation of dermal thickening in vivo(P˂0.05). Consistent with this we observed significant reduction in fibrogenic markers including αSMA, and collagen expression in the skin (P˂0.05). Furthermore secretion of the inflammatory marker, IL-6 was significantly attenuated (P˂0.05). Conclusion: We have assessed the functional effects of the Brd inhibitor, JQ1, on SSc dermal fibroblasts and the development of dermal fibrosis in a pre-clinical model of dermal fibrosis. We demonstrate that JQ1 markedly attenuated the excessive deposition and processing of collagen type I by SSc fibroblasts. In keeping with Brd proteins playing a pivotal role in the development and progression of dermal fibrosis, JQ1 significantly inhibited ECM deposition in vivo. Our data suggests a key role for Brd proteins in the persistence of the SSc dermal fibroblast phenotype

Analysis of the 2020 Taal Volcano tephra fall deposits from crowdsourced information and field data

International audienceAfter 43 years of dormancy, Taal Volcano violently erupted in January 2020 forming a towering eruption plume. The fall deposits covered an area of 8605 km2, which includes Metro Manila of the National Capital Region of the Philippines. The tephra fall caused damage to crops, traffic congestion, roof collapse, and changes in air quality in the affected areas. In a tropical region where heavy rains are frequent, immediate collection of data is crucial in order to preserve the tephra fall deposit record, which is readily washed away by surface water runoff and prevailing winds. Crowdsourcing, field surveys, and laboratory analysis of the tephra fall deposits were conducted to document and characterize the tephra fall deposits of the 2020 Taal Volcano eruption and their impacts. Results show that the tephra fall deposit thins downwind exponentially with a thickness half distance of about 1.40 km and 9.49 km for the proximal and distal exponential segments, respectively. The total calculated volume of erupted fallout deposit is 0.057 km3, 0.042 km3, or 0.090 km3 using the exponential, power-law, and Weibull models, respectively, and all translate to a VEI of 3. However, using a probabilistic approach (Weibull method) with 90% confidence interval, the volume estimate is as high as 0.097 km3. With the addition of the base surge deposits amounting to 0.019 km3, the volume translates to a VEI of 4, consistent with the classification for the observed height and umbrella radius of the 2020 main eruption plume. VEI 4 is also consistent with the calculated median eruption plume height of 17.8 km and sub-plinian classification based on combined analysis of isopleth and isopach data. Phreatomagmatic activity originated from a vent located in Taal Volcano's Main Crater Lake (MCL), which contained 42 million m3 of water. This eruptive style is further supported by the characteristics of the ash grain components of the distal 12 January 2020 tephra fall deposits, consisting dominantly of andesitic vitric fragments (83-90%). Other components of the fall deposits are lithic (7-11%) and crystal (less than 6%) grains. Further textural and geochemical analysis of these tephra fall deposits contributes to better understand the volcanic processes that occurred at Taal Volcano, one of the 16 Decade Volcanoes identified by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) because of its destructive nature and proximity to densely populated areas. The crowdsourcing initiative provided a significant portion of the data used for this study while at the same time educating and empowering the community to build resilience