Novel high-yield potato protease inhibitor panels block a wide array of proteases involved in viral infection and crucial tissue damage.

Viruses critically rely on various proteases to ensure host cell entry and replication. In response to viral infection, the host will induce acute tissue inflammation pulled by granulocytes. Upon hyperactivation, neutrophil granulocytes may cause undue tissue damage through proteolytic degradation of the extracellular matrix. Here, we assess the potential of protease inhibitors (PI) derived from potatoes in inhibiting viral infection and reducing tissue damage. The original full spectrum of potato PI was developed into five fractions by means of chromatography and hydrolysis. Individual fractions showed varying inhibitory efficacy towards a panel of proteases including trypsin, chymotrypsin, ACE2, elastase, and cathepsins B and L. The fractions did not interfere with SARS-CoV-2 infection of Vero E6 cells in vitro. Importantly, two of the fractions fully inhibited elastin-degrading activity of complete primary human neutrophil degranulate. These data warrant further development of potato PI fractions for biomedical purposes, including tissue damage crucial to SARS-CoV-2 pathogenesis. KEY MESSAGES: Protease inhibitor fractions from potato differentially inhibit a series of human proteases involved in viral replication and in tissue damage by overshoot inflammation. Protease inhibition of cell surface receptors such as ACE2 does not prevent virus infection of Vero cells in vitro. Protease inhibitors derived from potato can fully inhibit elastin-degrading primary human neutrophil proteases. Protease inhibitor fractions can be produced at high scale (hundreds of thousands of kilograms, i.e., tons) allowing economically feasible application in lower and higher income countries.

Comprehensive overview of the quality of plant- And animal-sourced proteins based on the digestible indispensable amino acid score.

Indispensable amino acid (IAA) composition and standardized ileal digestibility (SID) of five animal- and 12 plant-based proteins were used to calculate their respective Digestible Indispensable Amino Score (DIAAS) according to the three age categories defined by the Food and Agriculture Organization (FAO). Mean IAA content and mean SID obtained from each protein dataset were subsequently used to simulate optimal nutritional quality of protein mixtures. Datasets revealed considerable variation in DIAAS within the same protein source and among different protein sources. Among the selected protein sources, and based on the 0.5- to 3-year-old reference pattern, pork meat, casein, egg, and potato proteins are classified as excellent quality proteins with an average DIAAS above 100. Whey and soy proteins are classified as high-quality protein with an average DIAAS ≥75. Gelatin, rapeseed, lupin, canola, corn, hemp, fava bean, oat, pea, and rice proteins are classified in the no quality claim category (DIAAS <75). Potato, soy, and pea proteins can complement a broad range of plant proteins, leading to higher DIAAS when supplied in the form of protein mixtures and at specific ratios. Such complementarity highlights the potential to achieve an optimal nutritional efficiency with plant proteins alone.

White Adipose Tissue Response of Obese Mice to Ambient Oxygen Restriction at Thermoneutrality: Response Markers Identified, but no WAT Inflammation.

Obesity is associated with white adipose tissue (WAT) hypoxia and inflammation. We aimed to test whether mild environmental oxygen restriction (OxR, 13% O2), imposing tissue hypoxia, triggers WAT inflammation in obese mice. Thirteen weeks diet-induced obese male adult C57BL/6JOlaHsd mice housed at thermoneutrality were exposed for five days to OxR versus normoxia. WAT and blood were isolated and used for analysis of metabolites and adipokines, WAT histology and macrophage staining, and WAT transcriptomics. OxR increased circulating levels of haemoglobin and haematocrit as well as hypoxia responsive transcripts in WAT and decreased blood glucose, indicating systemic and tissue hypoxia. WAT aconitase activity was inhibited. Macrophage infiltration as marker for WAT inflammation tended to be decreased, which was supported by down regulation of inflammatory genes S100a8, Ccl8, Clec9a, Saa3, Mgst2, and Saa1. Other down regulated processes include cytoskeleton remodelling and metabolism, while response to hypoxia appeared most prominently up regulated. The adipokines coiled-coil domain containing 3 (CCDC3) and adiponectin, as well as the putative WAT hormone cholecystokinin (CCK), were reduced by OxR on transcript (Cck, Ccdc3) and/or serum protein level (adiponectin, CCDC3). Conclusively, our data demonstrate that also in obese mice OxR does not trigger WAT inflammation. However, OxR does evoke a metabolic response in WAT, with CCDC3 and adiponectin as potential markers for systemic or WAT hypoxia.

Adipose tissue metabolism and inflammation are differently affected by weight loss in obese mice due to either a high-fat diet restriction or change to a low-fat diet.

Restriction of a high-fat diet (HFD) and a change to a low-fat diet (LFD) are two interventions that were shown to promote weight loss and improve parameters of metabolic health in obesity. Examination of the biochemical and molecular responses of white adipose tissue (WAT) to these interventions has not been performed so far. Here, male C57BL/6JOlaHsd mice, harboring an intact nicotinamide nucleotide transhydrogenase gene, were fed a purified 40 energy% HFD for 14 weeks to induce obesity. Afterward, mice were divided into three dietary groups: HFD (maintained on HFD), LFD (changed to LFD with identical ingredients), and HFD-CR (restricted to 70 % of the HFD). The effects of the interventions were examined after 5 weeks. Beneficial effects were seen for both HFD-CR and LFD (compared to HFD) regarding physiological parameters (body weight and fat mass) and metabolic parameters, including circulating insulin and leptin levels. Macrophage infiltration in WAT was reduced by both interventions, although more effectively by HFD-CR. Strikingly, molecular parameters in WAT differed between HFD-CR and LFD, with increased activation of mitochondrial carbohydrate and fat metabolism in HFD-CR mice. Our results confirm that restriction of the amount of dietary intake and reduction in the dietary energy content are both effective in inducing weight loss. The larger decrease in WAT inflammation and increase in mitochondrial carbohydrate metabolism may be due to a larger degree of energy restriction in HFD-CR, but could also be due to superior effectiveness of dietary restriction in weight loss strategies.

Quercetin induces hepatic lipid omega-oxidation and lowers serum lipid levels in mice.

Elevated circulating lipid levels are known risk factors for cardiovascular diseases (CVD). In order to examine the effects of quercetin on lipid metabolism, mice received a mild-high-fat diet without (control) or with supplementation of 0.33% (w/w) quercetin for 12 weeks. Gas chromatography and (1)H nuclear magnetic resonance were used to quantitatively measure serum lipid profiles. Whole genome microarray analysis of liver tissue was used to identify possible mechanisms underlying altered circulating lipid levels. Body weight, energy intake and hepatic lipid accumulation did not differ significantly between the quercetin and the control group. In serum of quercetin-fed mice, triglycerides (TG) were decreased with 14% (p<0.001) and total poly unsaturated fatty acids (PUFA) were increased with 13% (p<0.01). Palmitic acid, oleic acid, and linoleic acid were all decreased by 9-15% (p<0.05) in quercetin-fed mice. Both palmitic acid and oleic acid can be oxidized by omega (ω)-oxidation. Gene expression profiling showed that quercetin increased hepatic lipid metabolism, especially ω-oxidation. At the gene level, this was reflected by the up-regulation of cytochrome P450 (Cyp) 4a10, Cyp4a14, Cyp4a31 and Acyl-CoA thioesterase 3 (Acot3). Two relevant regulators, cytochrome P450 oxidoreductase (Por, rate limiting for cytochrome P450s) and the transcription factor constitutive androstane receptor (Car; official symbol Nr1i3) were also up-regulated in the quercetin-fed mice. We conclude that quercetin intake increased hepatic lipid ω-oxidation and lowered corresponding circulating lipid levels, which may contribute to potential beneficial effects on CVD.