The functional contribution of myofibroblasts in fibrosis is not well understood. Using a new genetic mouse model to track and isolate myofibroblasts, we performed gene expression profiling followed ...by biological validation to identify HE4 (encoding human epididymis protein 4, also known as WAP 4-disulfide core domain-2 or Wfdc2) as the most upregulated gene in fibrosis-associated myofibroblasts. The HE4 gene encodes for a putative serine protease inhibitor that is upregulated in human and mouse fibrotic kidneys and is elevated in the serum of patients with kidney fibrosis. HE4 suppresses the activity of multiple proteases, including serine proteases and matrix metalloproteinases, and specifically inhibits their capacity to degrade type I collagen. In particular, we identified two serine proteases, Prss35 and Prss23, as HE4 targets with functional relevance in kidney fibrosis. Administration of HE4-neutralizing antibodies accelerated collagen I degradation and inhibited fibrosis in three different mouse models of renal disease. Collectively these studies suggest that HE4 is a potential biomarker of renal fibrosis and a new therapeutic target.
Equations of state (EoS) for fluids have been a staple of engineering design and practice for over a century. Available EoS are based on the fitting of a closed-form analytical expression to suitable ...experimental data. The mathematical structure and the underlying physical model significantly restrain the applicability and accuracy of the resulting EoS. This contribution explores the issues surrounding the substitution of machine-learned models for analytical EoS. In particular, we describe, as a proof of concept, the effectiveness of a machine-learned model to replicate the statistical associating fluid theory (SAFT-VR Mie) EoS for pure fluids. To quantify the effectiveness of machine-learning techniques, a large set of pseudodata is obtained from the EoS and used to train the machine-learning models. We employ artificial neural networks and Gaussian process regression to correlate and predict thermodynamic properties such as critical pressure and temperature, vapor pressures, and densities of pure model fluids; these are performed on the basis of molecular descriptors. The comparisons between the machine-learned EoS and the surrogate data set suggest that the proposed approach shows promise as a viable technique for the correlation and prediction of thermophysical properties of fluids.
Methylation of CpG island promoters is an epigenetic event that can effectively silence transcription over multiple cell generations. Hypermethylation of the Rasal1 promoter contributes to activation ...of fibroblasts and progression of kidney fibrosis. Here, we explored whether such causative hypermethylation could be reversed through endogenous mechanisms and whether such reversal of hypermethylation is a constituent of the antifibrotic activity of bone morphogenic protein 7 (BMP7). We show that successful inhibition of experimental kidney fibrosis through administration of BMP7 associates with normalization of Rasal1 promoter hypermethylation. Furthermore, this reversal of pathologic hypermethylation was achieved specifically through Tet3-mediated hydroxymethylation. Collectively, our findings reveal a new mechanism that may be exploited to facilitate therapeutic DNA demethylation to reverse kidney fibrosis.
The recent emergence of the novel, pathogenic SARS-coronavirus 2 (SARS-CoV-2) in China and its rapid national and international spread pose a global health emergency. Cell entry of coronaviruses ...depends on binding of the viral spike (S) proteins to cellular receptors and on S protein priming by host cell proteases. Unravelling which cellular factors are used by SARS-CoV-2 for entry might provide insights into viral transmission and reveal therapeutic targets. Here, we demonstrate that SARS-CoV-2 uses the SARS-CoV receptor ACE2 for entry and the serine protease TMPRSS2 for S protein priming. A TMPRSS2 inhibitor approved for clinical use blocked entry and might constitute a treatment option. Finally, we show that the sera from convalescent SARS patients cross-neutralized SARS-2-S-driven entry. Our results reveal important commonalities between SARS-CoV-2 and SARS-CoV infection and identify a potential target for antiviral intervention.
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•SARS-CoV-2 uses the SARS-CoV receptor ACE2 for host cell entry•The spike protein of SARS-CoV-2 is primed by TMPRSS2•Antibodies against SARS-CoV spike may offer some protection against SARS-CoV-2
The emerging SARS-coronavirus 2 (SARS-CoV-2) threatens public health. Hoffmann and coworkers show that SARS-CoV-2 infection depends on the host cell factors ACE2 and TMPRSS2 and can be blocked by a clinically proven protease inhibitor. These findings might help to establish options for prevention and treatment.
Autophagy is an essential cellular process affecting virus infections and other diseases and Beclin1 (BECN1) is one of its key regulators. Here, we identified S-phase kinase-associated protein 2 ...(SKP2) as E3 ligase that executes lysine-48-linked poly-ubiquitination of BECN1, thus promoting its proteasomal degradation. SKP2 activity is regulated by phosphorylation in a hetero-complex involving FKBP51, PHLPP, AKT1, and BECN1. Genetic or pharmacological inhibition of SKP2 decreases BECN1 ubiquitination, decreases BECN1 degradation and enhances autophagic flux. Middle East respiratory syndrome coronavirus (MERS-CoV) multiplication results in reduced BECN1 levels and blocks the fusion of autophagosomes and lysosomes. Inhibitors of SKP2 not only enhance autophagy but also reduce the replication of MERS-CoV up to 28,000-fold. The SKP2-BECN1 link constitutes a promising target for host-directed antiviral drugs and possibly other autophagy-sensitive conditions.
Fibrogenesis is a pathological wound repair process that fails to cease, even when the initial insult has been removed. Fibroblasts are principal mediators of fibrosis, and fibroblasts from fibrotic ...tissues fail to return to their quiescent stage, including when cultured in vitro. In a search for underlying molecular mechanisms, we hypothesized that this perpetuation of fibrogenesis is caused by epigenetic modifications. We demonstrate here that hypermethylation of RASAL1, encoding an inhibitor of the Ras oncoprotein, is associated with the perpetuation of fibroblast activation and fibrogenesis in the kidney. RASAL1 hypermethylation is mediated by the methyltransferase Dnmt1 in renal fibrogenesis, and kidney fibrosis is ameliorated in Dnmt1(+/-) heterozygous mice. These studies demonstrate that epigenetic modifications may provide a molecular basis for perpetuated fibroblast activation and fibrogenesis in the kidney.
The question of whether animals have emotions and respond to the emotional expressions of others has become a focus of research in the last decade 1–9. However, to date, no study has convincingly ...shown that animals discriminate between emotional expressions of heterospecifics, excluding the possibility that they respond to simple cues. Here, we show that dogs use the emotion of a heterospecific as a discriminative cue. After learning to discriminate between happy and angry human faces in 15 picture pairs, whereby for one group only the upper halves of the faces were shown and for the other group only the lower halves of the faces were shown, dogs were tested with four types of probe trials: (1) the same half of the faces as in the training but of novel faces, (2) the other half of the faces used in training, (3) the other half of novel faces, and (4) the left half of the faces used in training. We found that dogs for which the happy faces were rewarded learned the discrimination more quickly than dogs for which the angry faces were rewarded. This would be predicted if the dogs recognized an angry face as an aversive stimulus. Furthermore, the dogs performed significantly above chance level in all four probe conditions and thus transferred the training contingency to novel stimuli that shared with the training set only the emotional expression as a distinguishing feature. We conclude that the dogs used their memories of real emotional human faces to accomplish the discrimination task.
•We demonstrate that pet dogs can discriminate emotional expressions in human faces•We can rule out that discrimination was based on simple local cues•This ability may depend on extensive interaction with humans and/or domestication•Dogs probably use their memories of real emotional human faces to accomplish the task
Müller et al. demonstrate that pet dogs can discriminate emotional expressions in human faces. With an innovative paradigm, they can rule out that discrimination was based on simple cues, such as the visibility of teeth. Their study provides the first solid evidence for the ability of a non-human animal to discriminate emotions of another species.
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