Targeting mechanotransduction in myofibroblast like cells

Mechanical stimuli applied by the extracellular matrix (ECM) and the cells play an important role in the maintenance of tissue homeostasis. Mechanosensing and mechanotransduction are two processes by which cells transform mechanical forces into biochemical signals and adapt to changes in the microenvironment. Imbalanced cell response can create a positive feedback loop and lead to the pathological conditions, such as pancreatic ductal adenocarcinoma, which is characterised by the presence of extensive fibrotic stroma produced and maintained by pancreatic stellate cells (PSC). Here, it is shown that PSC are reversibly activated through mechanosensing of fibrosis-mimicking stiff substrates. Under the application of this mechanical cue, PSC exhibit rigidity-guided movement (durotaxis). This pattern of migration, which is regulated by a stiffness-dependent asymmetric distribution of active and inactive focal adhesion protein, is also observed in hepatic stellate cells (HSC). HSC, durotactically migrating to the fibrotic sites, can perpetuate the disease through their stiffness-initiated activation and resulting aberrant matrix remodelling capabilities. Experiments revealed a mechanical network allowing HSC to maintain fibrotic ECM by decreasing the matrix-digesting enzyme MMP-9 expression and activity, and increasing the activity of its secreted inhibitor, TIMP-1. Furthermore, these results shed light on a new mechanism, through which stiff matrix can initiate exocytosis. This is identified as an effect of membrane homeostasis maintenance, where an increase in plasma membrane tension via β1 integrin mechanosensing and RhoA activation is followed by tension-relieving secretion. With RhoA and cell activation as a common factor in the cell mechanical response, final experiments focused on G protein-coupled receptor (GPER), here identified as a novel mechanoregulator in fibroblasts. GPER activation decreases RhoA activity and impacts overall mechanical response in cells, opening new possibilities for potential therapies in cancer and fibrosis.Open Acces

Treatment of degenerative cervical spondylosis with radiculopathy. Clinical practice guidelines endorsed by The Polish Society of Spinal Surgery

Introduction Degenerative cervical spondylosis (DCS) with radiculopathy is the most common indication for cervical spine surgery despite favorable natural history. Advances in spinal surgery in conjunction with difficulties in measuring the outcomes caused the paucity of uniform guidelines for the surgical management of DCS. Aims The aim of this paper is to develop guidelines for surgical treatment of DCS. For this purpose the available up-to-date literature relevant on the topic was critically reviewed. Methods and results Six questions regarding most important clinical questions encountered in the daily practice were formulated. They were answered based upon the systematic literature review, thus creating a set of guidelines. The guidelines were categorized into four tiers based on the level of evidence (I–III and X). They were designed to assist in the selection of optimal and effective treatment leading to the most successful outcome. Conclusions The evidence based medicine (EBM) is increasingly popular among spinal surgeons. It allows making unbiased, optimal clinical decisions, eliminating the detrimental effect of numerous conflicts of interest. The key role of opinion leaders as well as professional societies is to provide guidelines for practice based on available clinical evidence. The present work contains a set of guidelines for surgical treatment of DCS officially endorsed by the Polish Spine Surgery Society

Treatment of lumbar disc herniation with radiculopathy. Clinical practice guidelines endorsed by The Polish Society of Spinal Surgery

Introduction Herniated lumbar disc (HLD) is arguably the most common spinal disorder requiring surgical intervention. Although the term is fairly straightforward, the exact pathology and thus the clinical picture and natural history may vary. Therefore, it is immensely difficult to formulate universal guidelines for surgical treatment. Aim The aim of this paper is to organize the terminology and clear the inconsistencies in phraseology, review treatment options and gather available published evidence to address the clinical questions to create a set of clinical guidelines in relevant to the topic. Methods and results Twelve queries, addressing optimal surgical treatment of the HLD have been formulated. The results, based on the literature review are described in the present work. The final product of the analysis was a set of guidelines for the surgical treatment of symptomatic HLD. Categorized into four tiers based on the level of evidence (I–III and X), they have been designed to assist in the selection of optimal, effective treatment leading to the successful outcome. Conclusions The evidence based medicine (EBM) is becoming ever more popular among spinal surgeons. Unfortunately this is not always feasible. Lack of uniform guidelines and numerous conflicts of interest introduce flaws in the decision making process. The key role of experts and professional societies is to provide high value recommendation based on the most current literature. Present work contains a set of guidelines for the surgical treatment of HLD officially endorsed by the Polish Spine Surgery Society

Self-Assembling Polypeptide Hydrogels as a Platform to Recapitulate the Tumor Microenvironment

From MDPI via Jisc Publications RouterHistory: accepted 2021-06-25, pub-electronic 2021-06-30Publication status: PublishedFunder: Innovate UKRI Research Knowledge Transfer Partnership; Grant(s): KTP: Self-assembling peptide matrices as a platform for cell biology studies and drug deliveryThe tumor microenvironment plays a critical role in modulating cancer cell migration, metabolism, and malignancy, thus, highlighting the need to develop in vitro culture systems that can recapitulate its abnormal properties. While a variety of stiffness-tunable biomaterials, reviewed here, have been developed to mimic the rigidity of the tumor extracellular matrix, culture systems that can recapitulate the broader extracellular context of the tumor microenvironment (including pH and temperature) remain comparably unexplored, partially due to the difficulty in independently tuning these parameters. Here, we investigate a self-assembled polypeptide network hydrogel as a cell culture platform and demonstrate that the culture parameters, including the substrate stiffness, extracellular pH and temperature, can be independently controlled. We then use this biomaterial as a cell culture substrate to assess the effect of stiffness, pH and temperature on Suit2 cells, a pancreatic cancer cell line, and demonstrate that these microenvironmental factors can regulate two critical transcription factors in cancer: yes-associated protein 1 (YAP) and hypoxia inducible factor (HIF-1A)

Tamoxifen mechanically deactivates hepatic stellate cells via the G protein-coupled estrogen receptor

Tamoxifen has been used for many years to target estrogen receptor signalling in breast cancer cells. Tamoxifen is also an agonist of the G protein-coupled estrogen receptor (GPER), a GPCR ubiquitously expressed in tissues that mediates the acute response to estrogens. Here we report that tamoxifen promotes mechanical quiescence in hepatic stellate cells (HSCs), stromal fibroblast-like cells whose activation triggers and perpetuates liver fibrosis in hepatocellular carcinomas. This mechanical deactivation is mediated by the GPER/RhoA/myosin axis and induces YAP deactivation. We report that tamoxifen decreases the levels of hypoxia-inducible factor-1 alpha (HIF-1α) and the synthesis of extracellular matrix proteins through a mechanical mechanism that involves actomyosin-dependent contractility and mechanosensing of tissue stiffness. Our results implicate GPER-mediated estrogen signalling in the mechanosensory-driven activation of HSCs and put forward estrogenic signalling as an option for mechanical reprogramming of myofibroblast-like cells in the tumour microenvironment. Tamoxifen, with half a century of safe clinical use, might lead this strategy of drug repositioning.Peer reviewe

Syndecan-4 tunes cell mechanics by activating the kindlin-integrin-RhoA pathway

A mechanism of cell response to localized tension shows that syndecan-4 synergizes with EGFR to elicit a mechanosignalling cascade that leads to adaptive cell stiffening through PI3K/kindlin-2 mediated integrin activation. Extensive research over the past decades has identified integrins to be the primary transmembrane receptors that enable cells to respond to external mechanical cues. We reveal here a mechanism whereby syndecan-4 tunes cell mechanics in response to localized tension via a coordinated mechanochemical signalling response that involves activation of two other receptors: epidermal growth factor receptor and beta 1 integrin. Tension on syndecan-4 induces cell-wide activation of the kindlin-2/beta 1 integrin/RhoA axis in a PI3K-dependent manner. Furthermore, syndecan-4-mediated tension at the cell-extracellular matrix interface is required for yes-associated protein activation. Extracellular tension on syndecan-4 triggers a conformational change in the cytoplasmic domain, the variable region of which is indispensable for the mechanical adaptation to force, facilitating the assembly of a syndecan-4/alpha-actinin/F-actin molecular scaffold at the bead adhesion. This mechanotransduction pathway for syndecan-4 should have immediate implications for the broader field of mechanobiology.Peer reviewe

Tamoxifen mechanically reprograms the tumor microenvironment via HIF‐1A and reduces cancer cell survival

The tumor microenvironment is fundamental to cancer progression, and the influence of its mechanical properties is increasingly being appreciated. Tamoxifen has been used for many years to treat estrogen‐positive breast cancer. Here we report that tamoxifen regulates the level and activity of collagen cross‐linking and degradative enzymes, and hence the organization of the extracellular matrix, via a mechanism involving both the G protein‐coupled estrogen receptor (GPER) and hypoxia‐inducible factor‐1 alpha (HIF‐1A). We show that tamoxifen reduces HIF‐1A levels by suppressing myosin‐dependent contractility and matrix stiffness mechanosensing. Tamoxifen also downregulates hypoxia‐regulated genes and increases vascularization in PDAC tissues. Our findings implicate the GPER/HIF‐1A axis as a master regulator of peri‐tumoral stromal remodeling and the fibrovascular tumor microenvironment and offer a paradigm shift for tamoxifen from a well‐established drug in breast cancer hormonal therapy to an alternative candidate for stromal targeting strategies in PDAC and possibly other cancers.See also: E Cortes et al (January 2019) andM Pein & T Oskarsson (January 2019)EMBO Reports (2019) 20: e46557Peer reviewe

Tamoxifen mechanically deactivates hepatic stellate cells via the G protein-coupled estrogen receptor

Tamoxifen has been used for many years to target estrogen receptor signalling in breast cancer cells. Tamoxifen is also an agonist of the G protein-coupled estrogen receptor (GPER), a GPCR ubiquitously expressed in tissues that mediates the acute response to estrogens. Here we report that tamoxifen promotes mechanical quiescence in hepatic stellate cells (HSCs), stromal fibroblast-like cells whose activation triggers and perpetuates liver fibrosis in hepatocellular carcinomas. This mechanical deactivation is mediated by the GPER/RhoA/myosin axis and induces YAP deactivation. We report that tamoxifen decreases the levels of hypoxia-inducible factor-1 alpha (HIF-1α) and the synthesis of extracellular matrix proteins through a mechanical mechanism that involves actomyosin-dependent contractility and mechanosensing of tissue stiffness. Our results implicate GPER-mediated estrogen signalling in the mechanosensory-driven activation of HSCs and put forward estrogenic signalling as an option for mechanical reprogramming of myofibroblast-like cells in the tumour microenvironment. Tamoxifen, with half a century of safe clinical use, might lead this strategy of drug repositioning.Peer reviewe

Self-Assembling Polypeptide Hydrogels as a Platform to Recapitulate the Tumor Microenvironment

The tumor microenvironment plays a critical role in modulating cancer cell migration, metabolism, and malignancy, thus, highlighting the need to develop in vitro culture systems that can recapitulate its abnormal properties. While a variety of stiffness-tunable biomaterials, reviewed here, have been developed to mimic the rigidity of the tumor extracellular matrix, culture systems that can recapitulate the broader extracellular context of the tumor microenvironment (including pH and temperature) remain comparably unexplored, partially due to the difficulty in independently tuning these parameters. Here, we investigate a self-assembled polypeptide network hydrogel as a cell culture platform and demonstrate that the culture parameters, including the substrate stiffness, extracellular pH and temperature, can be independently controlled. We then use this biomaterial as a cell culture substrate to assess the effect of stiffness, pH and temperature on Suit2 cells, a pancreatic cancer cell line, and demonstrate that these microenvironmental factors can regulate two critical transcription factors in cancer: yes-associated protein 1 (YAP) and hypoxia inducible factor (HIF-1A)