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Aim: Calcineurin inhibitors (CNIs) are the backbone for immunosuppression after solid organ transplantation. Although successful in preventing kidney transplant rejection, their nephrotoxic side effects contribute to allograft injury. Renal parenchymal lesions occur for cyclosporine A (CsA) as well as for the currently favored tacrolimus (Tac). We aimed to study whether chronic CsA and Tac exposures, before reaching irreversible nephrotoxic damage, affect renal compartments differentially and whether related pathogenic mechanisms can be identified., Methods: CsA and Tac were administered chronically in wild type Wistar rats using osmotic minipumps over 4 weeks. Functional parameters were controlled. Electron microscopy, confocal, and 3D-structured illumination microscopy were used for histopathology. Clinical translatability was tested in human renal biopsies. Standard biochemical, RNA-seq, and proteomic technologies were applied to identify implicated molecular pathways., Results: Both drugs caused significant albeit differential damage in vasculature and nephron. The glomerular filtration barrier was more affected by Tac than by CsA, showing prominent deteriorations in endothelium and podocytes along with impaired VEGF/VEGFR2 signaling and podocyte-specific gene expression. By contrast, proximal tubule epithelia were more severely affected by CsA than by Tac, revealing lysosomal dysfunction, enhanced apoptosis, impaired proteostasis and oxidative stress. Lesion characteristics were confirmed in human renal biopsies., Conclusion: We conclude that pathogenetic alterations in the renal compartments are specific for either treatment. Considering translation to the clinical setting, CNI choice should reflect individual risk factors for renal vasculature and tubular epithelia. As a step in this direction, we share protein signatures identified from multiomics with potential pathognomonic relevance., (© 2024 The Author(s). Acta Physiologica published by John Wiley & Sons Ltd on behalf of Scandinavian Physiological Society.)

As the death toll of Coronavirus disease 19 (COVID-19) continues to rise worldwide, it is imperative to explore novel molecular mechanisms for targeting SARS-CoV-2. Rather than looking for drugs that directly interact with key viral proteins inhibiting its replication, an alternative and possibly add-on approach is to dismantle the host cell machinery that enables the virus to infect the host cell and spread from one cell to another. Excellent examples of such machinery are host cell proteases whose role in viral pathogenesis has been demonstrated in numerous coronaviruses. In this review, we propose two therapeutic modalities to tackle SARS-CoV-2 infections; the first is to transcriptionally modulate the expression of cellular proteases and their endogenous inhibitors and the second is to directly inhibit their enzymatic activity. We present a nonexhaustive collection of clinically investigated drugs that act by one of these mechanisms and thus represent promising candidates for preclinical in vitro testing and hopefully clinical testing in COVID-19 patients., (© 2020 The Authors. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics.)

Oncogenic mutations in KRAS or BRAF are frequent in colorectal cancer and activate the ERK kinase. Here, we find graded ERK phosphorylation correlating with cell differentiation in patient-derived colorectal cancer organoids with and without KRAS mutations. Using reporters, single cell transcriptomics and mass cytometry, we observe cell type-specific phosphorylation of ERK in response to transgenic KRAS G12V in mouse intestinal organoids, while transgenic BRAF V600E activates ERK in all cells. Quantitative network modelling from perturbation data reveals that activation of ERK is shaped by cell type-specific MEK to ERK feed forward and negative feedback signalling. We identify dual-specificity phosphatases as candidate modulators of ERK in the intestine. Furthermore, we find that oncogenic KRAS, together with β-Catenin, favours expansion of crypt cells with high ERK activity. Our experiments highlight key differences between oncogenic BRAF and KRAS in colorectal cancer and find unexpected heterogeneity in a signalling pathway with fundamental relevance for cancer therapy.

Microglia, the brain innate immune cells, are activated in response to amyloid beta (Aβ) resulting in neuroinflammation in AD brains. Recently, two phenotypes have been described for microglia: the pro-inflammatory classical and the anti-inflammatory alternative. Changes in microglia phenotype that control their phagocytic function are yet to be determined. The highly neurotoxic Aβ oligomers (oAβ) formed at an early disease stage induce pro-inflammatory microglia activation releasing neurotoxic mediators and contributing to neurodegeneration. A novel strategy for AD treatment is to attenuate microglia-induced inflammation while maintaining efficient Aβ clearance. Minocycline effectively crosses the blood-brain barrier and has widely reported neuroprotective effects. Yet, its exact mechanism of neuroprotection and its effects on microglia are still unknown. The aim of this study is to investigate the effect of minocycline on the phagocytic uptake of fAβ by primary microglia in relation to their activation state in an inflammatory milieu generated by oAβ or LPS. The study shows that minocycline is able to attenuate oAβ-induced neuroinflammatory response of microglia by inhibiting their pro-inflammatory phenotype activation. In addition, a significant enhancement of fAβ phagocytosis by minocycline- treated microglia is reported for the first time, providing novel insight into its neuroprotective role in AD., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)