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Simple Summary: Our study examined how muscle function is affected in cancer patients, particularly those at risk of developing muscle wasting (cachexia). We tested a combination of mild exercise and a protein-rich diet as a potential preventive measure. By analysing muscle fibres from patients undergoing different treatments, we found that cancer cachexia leads to muscle weakness and stiffness. However, our results show that the combined therapy helps maintain muscle flexibility and function. This suggests that such an intervention could improve the quality of life for cancer patients by preserving muscle health. Patients with aggressive cancer, e.g., gastrointestinal cancer, are prone (≥50% chance) to developing cancer cachexia (CC). Little is known about the effects of CC on the biomechanical function of muscle. A promising prevention strategy was found in the form of a multi-modal therapy combining mild resistance exercise (e.g., whole-body electro-myostimulation, WB-EMS) and a protein-rich diet. In a previous study of ours, this was effective in counteracting the loss of muscle mass, yet a systematic and comprehensive assessment of active and passive single muscle fibre functions was so far absent. This pilot study investigated the biomechanical function of single muscle fibres (rectus abdominis) from the biopsies of conventionally treated (pre-)cachectic cancer ((pre-)CC) patients (m = 9), those receiving the multi-modal therapy comprising WB-EMS training and protein-rich nutrition (m = 3), and a control group (m = 5). Our findings not only align with previous findings showing the absolute force loss in CC that is accelerated by atrophy but also speak in favour of a different, potentially energy- and Ca2+-homeostasis-related effect that compromises muscle contraction (F ~0.9 mN vs. F ~0.6 mN in control patients). However, myofibrillar Ca2+ sensitivity and the quality of contraction were unaltered (pCa50: 5.6–5.8). Single fibres from the (pre-)CC patients receiving WB-EMS training and protein supplementation were significantly more compliant (p < 0.001 at ≥130% of resting length L0). Those fibres displayed a similar softness to the ones from the control patients (axial compliance ~15 m/N at ≥130% L0), while single fibres from the patients with (developing) cachexia were significantly stiffer (axial compliance ~7 m/N, p < 0.001 at ≥130% L0). Adjuvant multi-modal therapy (WB-EMS training and nutritional support) contributes to maintaining the axial compliance of single fibres and potentially improves the quality of life for patients at risk of developing CC. [ABSTRACT FROM AUTHOR]

The importance of mechanosensory transduction pathways in cellular signalling has prominently come to focus in the last decade with the discovery of the Piezo ion channel family. Mechanosignaling involving Piezo1 ion channels in the function of the heart and cardiovascular system has only recently been identified to have implications for cardiovascular physiology and pathophysiology, in particular for heart failure (i.e., hypertrophy or dilative cardiomyopathy). These results have emphasized the need for higher throughput methods to study single-cell cardiovascular mechanobiology with the aim of identifying new targets for therapeutic interventions and stimulating the development of new pharmacological agents. Here, we present a novel method to assess mechanosignaling in adherent cardiac cells (murine HL-1 cell line) using a combination of isotropic cell stretch application and simultaneous Ca2+ fluorescence readout with quantitative analysis. The procedure implements our IsoStretcher technology in conjunction with a single-cell- and population-based analysis of Ca2+ signalling by means of automated image registration, cell segmentation and analysis, followed by automated classification of single-cell responses. The method is particularly valuable for assessing the heterogeneity of populations with distinct cellular responses to mechanical stimulation and provides more user-independent unbiased drug response classifications. [ABSTRACT FROM AUTHOR]

The importance of mechanosensory transduction pathways in cellular signalling has prominently come to focus in the last decade with the discovery of the Piezo ion channel family. Mechanosignaling involving Piezo1 ion channels in the function of the heart and cardiovascular system has only recently been identified to have implications for cardiovascular physiology and pathophysiology, in particular for heart failure (i.e., hypertrophy or dilative cardiomyopathy). These results have emphasized the need for higher throughput methods to study single-cell cardiovascular mechanobiology with the aim of identifying new targets for therapeutic interventions and stimulating the development of new pharmacological agents. Here, we present a novel method to assess mechanosignaling in adherent cardiac cells (murine HL-1 cell line) using a combination of isotropic cell stretch application and simultaneous Ca 2+ fluorescence readout with quantitative analysis. The procedure implements our IsoStretcher technology in conjunction with a single-cell- and population-based analysis of Ca 2+ signalling by means of automated image registration, cell segmentation and analysis, followed by automated classification of single-cell responses. The method is particularly valuable for assessing the heterogeneity of populations with distinct cellular responses to mechanical stimulation and provides more user-independent unbiased drug response classifications., (© 2024. The Author(s).)

Malaria is one of the most widespread diseases worldwide. Besides a growing number of people potentially threatened by malaria, the consistent emergence of resistance against established antimalarial pharmaceuticals leads to an urge toward new antimalarial drugs. Hybridization of two chemically diverse compounds into a new bioactive product is a successful concept to improve the properties of a hybrid drug relative to the parent compounds and also to overcome multidrug resistance. 1,2,3-Triazoles are a significant pharmacophore system among nitrogen-containing heterocycles with various applications, such as antiviral, antimalarial, antibacterial, and anticancer agents. Several marketed drugs possess these versatile moieties, which are used in a wide range of medical indications. While the synthesis of hybrid compounds containing a 1,2,3-triazole unit was described using Cu- and Ru-catalyzed azide-alkyne cycloaddition, an alternative metal-free pathway has never been reported for the synthesis of antimalarial hybrids. However, a metal-free pathway is a green method that allows toxic and expensive metals to be replaced with an organocatalyst. Herein, we present the synthesis of new artemisinin-triazole antimalarial hybrids via a facile Ramachary-Bressy-Wang organocatalyzed azide-carbonyl [3 + 2] cycloaddition (organo-click) reaction. The prepared new hybrid compounds are highly potent in vitro against chloroquine (CQ)-resistant and multi-drug-resistant Plasmodium falciparum strains (IC 50 (Dd2) down to 2.1 nM; IC 50 (K1) down to 1.8 nM) compared to CQ (IC 50 (Dd2) = 165.3 nM; IC 50 (K1) = 302.8 nM). Moreover, the most potent hybrid drug was more efficacious in suppressing parasitemia and extending animal survival in Plasmodium berghei -infected mice (up to 100% animal survival and up to 40 days of survival time) than the reference drug artemisinin, illustrating the potential of the hybridization concept as an alternative and powerful drug-discovery approach., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

The recently discovered ion channel TMEM63A has biophysical features distinctive for mechano-gated cation channels, activating at high pressures with slow kinetics while not inactivating. However, some biophysical properties are less clear, including no information on its function in whole cells. The aim of this study is to expand the TMEM63A biophysical characterization and examine the function in whole cells. Piezo1-knockout HEK293T cells were cotransfected with human TMEM63A and green fluorescent protein (GFP), and macroscopic currents in cell-attached patches were recorded by high-speed pressure clamp at holding voltages from -120 to -20 mV with 0-100 mmHg patch suction for 1 s. HEK293 cells cotransfected with TMEM63A and GCaMP5 were seeded onto polydimethylsiloxane (PDMS) membrane, and the response to 3-12 s of 1%-15% whole cell isotropic (equi-biaxial) stretch induced by an IsoStretcher was measured by the change in intracellular calcium ([Ca 2+ ] i ) and presented as (ΔF/F 0 > 1). Increasing patch pressures activated TMEM63A currents with accelerating activation kinetics and current amplitudes that were pressure dependent but voltage independent. TMEM63A currents were plateaued within 2 s, recovered quickly, and were sensitive to Gd 3+ . In whole cells stretched on flexible membranes, radial stretch increased the [Ca 2+ ] i responses in a larger proportion of cells cotransfected with TMEM63A and GCaMP5 than GCaMP5-only controls. TMEM63A currents are force activated and voltage insensitive, have a high threshold for pressure activation with slow activation and deactivation, and lack inactivation over 5 s. TMEM63A has the net polarity and kinetics that would depolarize plasma membranes and increase inward currents, contributing to a sustained [Ca 2+ ] i increase in response to high stretch. NEW & NOTEWORTHY TMEM63A has biophysical features distinctive for mechano-gated cation channels, but some properties are less clear, including no functional information in whole cells. We report that pressure-dependent yet voltage-independent TMEM63A currents in cell membrane patches correlated with cell size. In addition, radial stretch of whole cells on flexible membranes increased the [Ca 2+ ] i responses more in TMEM63A-transfected cells. Inward TMEM63A currents in response to high stretch can depolarize plasma membranes and contribute to a sustained [Ca 2+ ] i increase.