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1. YAP-mediated mechanotransduction tunes the macrophage inflammatory response

   https://doi.org/10.1126/sciadv.abb8471  

   Meli, Vijaykumar S.; Atcha, Hamza; Veerasubramanian, Praveen Krishna; Nagalla, Raji R.; Luu, Thuy U.; Chen, Esther Y.; Guerrero-Juarez, Christian F.; Yamaga, Kosuke; Pandori, William; Hsieh, Jessica Y.; et al (December 2020, Science Advances)

   null (Ed.)

   Macrophages are innate immune cells that adhere to the extracellular matrix within tissues. However, how matrix properties regulate their function remains poorly understood. Here, we report that the adhesive microenvironment tunes the macrophage inflammatory response through the transcriptional coactivator YAP. We find that adhesion to soft hydrogels reduces inflammation when compared to adhesion on stiff materials and is associated with reduced YAP expression and nuclear localization. Substrate stiffness and cytoskeletal polymerization, but not adhesive confinement nor contractility, regulate YAP localization. Furthermore, depletion of YAP inhibits macrophage inflammation, whereas overexpression of active YAP increases inflammation. Last, we show in vivo that soft materials reduce expression of inflammatory markers and YAP in surrounding macrophages when compared to stiff materials. Together, our studies identify YAP as a key molecule for controlling inflammation and sensing stiffness in macrophages and may have broad implications in the regulation of macrophages in health and disease. 

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2. Pre-clinical safety and therapeutic efficacy of a plant-based alkaloid in a human colon cancer xenograft model

   https://doi.org/10.1038/s41420-022-00936-3  

   Freeling, Jessica L.; Scholl, Jamie L.; Eikanger, Morgan; Knoblich, Cole; Potts, Rashaun A.; Anderson, David J.; Rower, Joseph E.; Farjoo, Mohammad Hadi; Zhao, Haotian; Pillatzki, Angela; et al (December 2022, Cell Death Discovery)

   Abstract A high-throughput drug screen revealed that veratridine (VTD), a natural plant alkaloid, induces expression of the anti-cancer protein UBXN2A in colon cancer cells. UBXN2A suppresses mortalin, a heat shock protein, with dominant roles in cancer development including epithelial–mesenchymal transition (EMT), cancer cell stemness, drug resistance, and apoptosis. VTD-dependent expression of UBXN2A leads to the deactivation of mortalin in colon cancer cells, making VTD a potential targeted therapy in malignant tumors with high levels of mortalin. VTD was used clinically for the treatment of hypertension in decades past. However, the discovery of newer antihypertensive drugs and concerns over potential neuro- and cardiotoxicity ended the use of VTD for this purpose. The current study aims to determine the safety and efficacy of VTD at doses sufficient to induce UBXN2A expression in a mouse model. A set of flow-cytometry experiments confirmed that VTD induces both early and late apoptosis in a dose-dependent manner. In vivo intraperitoneal (IP) administration of VTD at 0.1 mg/kg every other day (QOD) for 4 weeks effectively induced expression of UBXN2A in the small and large intestines of mice. Liquid chromatography–tandem mass spectrometry (LC–MS/MS) assays on tissues collected from VTD-treated animals demonstrated VTD concentrations in the low pg/mg range. To address concerns regarding neuro- and cardiotoxicity, a comprehensive set of behavioral and cardiovascular assessments performed on C57BL/6NHsd mice revealed that VTD generates no detectable neurotoxicity or cardiotoxicity in animals receiving 0.1 mg/kg VTD QOD for 30 days. Finally, mouse xenograft experiments in athymic nude mice showed that VTD can suppress tumor growth. The main causes for the failure of experimental oncologic drug candidates are lack of sufficient safety and efficacy. The results achieved in this study support the potential utility of VTD as a safe and efficacious anti-cancer molecule. 

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3. Patients with obstructive sleep apnea have suppressed levels of soluble cytokine receptors involved in neurodegenerative disease, but normal levels with airways therapy

   https://doi.org/10.1007/s11325-020-02205-y  

   Wang, Ye; Meagher, Richard B.; Ambati, Suresh; Ma, Ping; Phillips, Bradley G. (October 2020, Sleep and Breathing)

   null (Ed.)

   Abstract Purpose Obstructive sleep apnea (OSA) results in systemic intermittent hypoxia. By one model, hypoxic stress signaling in OSA patients alters the levels of inflammatory soluble cytokines TNF and IL6, damages the blood brain barrier, and activates microglial targeting of neuronal cell death to increase the risk of neurodegenerative disorders and other diseases. However, it is not yet clear if OSA significantly alters the levels of the soluble isoforms of TNF receptors TNFR1 and TNFR2 and IL6 receptor (IL6R) and co-receptor gp130, which have the potential to modulate TNF and IL6 signaling. Methods Picogram per milliliter levels of the soluble isoforms of these four cytokine receptors were estimated in OSA patients, in OSA patients receiving airways therapy, and in healthy control subjects. Triplicate samples were examined using Bio-Plex fluorescent bead microfluidic technology. The statistical significance of cytokine data was estimated using the nonparametric Wilcoxon rank-sum test. The clustering of these high-dimensional data was visualized using t -distributed stochastic neighbor embedding (t-SNE). Results OSA patients had significant twofold to sevenfold reductions in the soluble serum isoforms of all four cytokine receptors, gp130, IL6R, TNFR1, and TNFR2, as compared with control individuals ( p  = 1.8 × 10 −13 to 4 × 10 −8 ). Relative to untreated OSA patients, airways therapy of OSA patients had significantly higher levels of gp130 ( p  = 2.8 × 10 −13 ), IL6R ( p  = 1.1 × 10 −9 ), TNFR1 ( p  = 2.5 × 10 −10 ), and TNFR2 ( p  = 5.7 × 10 −9 ), levels indistinguishable from controls ( p  = 0.29 to 0.95). The data for most airway-treated patients clustered with healthy controls, but the data for a few airway-treated patients clustered with apneic patients. Conclusions Patients with OSA have aberrantly low levels of four soluble cytokine receptors associated with neurodegenerative disease, gp130, IL6R, TNFR1, and TNFR2. Most OSA patients receiving airways therapy have receptor levels indistinguishable from healthy controls, suggesting a chronic intermittent hypoxia may be one of the factors contributing to low receptor levels in untreated OSA patients. 

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4. Mesenchymal Stem Cell Aging and Senescence Associated Extracellular Matrix Contributions to Breast Cancer Progression

   Ghosh, Deepraj; Quach, Nhat; Pena, Carolina; Xuan, Botai; Lee, Amy; Dawson, Michelle (February 2019, Gordon Research Conference: Physical Science of Cancer)

   Age is a leading risk factor for developing breast cancer. This may be in part to the time required for acquiring sufficient cancer mutations; however, stromal cells that accumulate in tissues and undergo senescence eventually develop a senescence-associated secretory phenotype that alters the microenvironment to promote cancer. Our focus is on mesenchymal stem cells (MSCs) – stromal cells recruited to tumors due to their natural tropism for inflammatory tissues; MSCs have been shown to enhance the metastatic potential of tumor cells through direct interactions or paracrine signaling within the tumor. In the tumor, MSCs can differentiate into carcinoma-associated fibroblasts that play a central role in tumor growth and matrix remodeling. We recently investigated the molecular and mechanical differences in pre- and post- senescent MSCs and how their interactions with MDA-MB-231 breast cancer cells contribute to malignancy. Our data show post-senescent MSCs are larger and less motile, with more homogeneous mechanical properties than pre-senescent MSCs. In-depth omics analysis revealed differentially regulated genes and peptides including factors related to inflammatory cytokines, cell adhesion to the extracellular matrix, and cytoskeletal regulation. A 3D co-culture model was used to assess the effects of pre- and post- senescent MSCs on collagen matrix remodeling. Although post-senescent MSCs were far less motile than pre-senescent MSCs and less contractile with the matrix, they profoundly altered matrix protein deposition and crosslinking, which resulted in local matrix stiffening effects. Post-senescent MSCs also induced an invasive breast cancer cell phenotype, characterized by increased proliferation and invasion of breast cancer cells. This invasive breast cancer cell behavior was further amplified when MDA-MB-231 was co-cultured with a mixture of pre- and post- senescent MSCs; this result was attributed to matrix remodeling and soluble factor secretion effects of post-senescent MSCs, which enhanced the migration of pre-senescent MSCs allowing them to form tracks in the collagen network for cancer cells to follow. Finally, molecular inhibitors targeting actomyosin contractility and adhesion were used to alter MSC interactions with breast cancer cells. Actin depolymerizing agent and focal adhesion kinase inhibitor were most efficient and completely able to block the effects of post-senescent MSCs on MDA-MB-231 invasion in collagen gels. This comprehensive approach can be used to identify molecular pathways regulating heterotypic interactions of post-senescent MSCs with other cells in the tumor. Furthermore, the local matrix stiffening effect of post-senescent MSCs may play a critical role in breast cancer progression. 

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5. Cellular Senescence Alters Tumor Microenvironment Interactions Forcing Cancer Progression

   Dawson, Michelle; Ghosh, Deepraj (July 2018, Gordon Research Conference: Signal Transduction by Engineered Extracellular Matrices)

   Mesenchymal stem cells (MSCs) that accumulate in the primary tumor due to their natural tropism for inflammatory tissues enhance the metastatic potential of tumor cells through direct interactions with tumor cells or paracrine signaling within the tumor microenvironment. MSCs also undergo senescence, which leads to increased production of pro-inflammatory cytokines and matrix-degrading enzymes. Senescence is a critical mechanism of limiting abnormal growth and cancer development through tumor suppression; however, senescent cells that accumulate in tissues eventually develop a senescence-associated secretory phenotype that alters the microenvironment to promote cancer. Increased understanding of the biophysical properties of senescent MSCs and how they mediate cell-cell interactions in the tumor may be useful in identifying novel biomarkers for senescent stromal cells in tissues or aggressive cancer cells that form in an aging stroma. A high-content single cell biophysical approach was used to define the mechanical properties of pre- and post- senescent MSCs. Our data shows post-senescent MSCs are larger and less motile, with more homogeneous mechanical properties than their pre-senescent counterparts. A robust molecular screening approach combining genome-wide microarray analysis with mass spec-based proteomics was used to establish the molecular differences in pre- and post- senescent MSCs. Our data show a consistent correlation of up and down regulated gene and peptide expression. A 3D co-culture model was used to assess the effects of pre- and post- senescent MSCs on breast cancer cell motility and invasion in 3D collagen gels. Post-senescent MSCs induced an invasive breast cancer cell phenotype, characterized by increased spreading of breast cancer cells in collagen, increased numbers of invading cells, and morphological elongation of breast cancer cells. Surprisingly, this invasive breast cancer cell behavior was further amplified when breast cancer cells were co-cultured with both pre- and post- senescent cells. 

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