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Dipeptidyl peptidase IV (DPPIV) is a serine protease, a member of the prolyl oligopeptidase (POP) family, and has been implicated in several diseases. Therefore, it seems important to develop selective inhibitors for human DPPIV (hDPPIV) that are able to control the biological function of hDPPIV. In order to elucidate the binding mode and substrate specificity, we determined the crystal structure complex of hDPPIV and diprotin A (Ile-Pro- Ile), a slowly hydrolyzed substrate of hDPPIV, at 2.2 Å resolution. In this paper, we discuss the molecular interaction mechanism of diprotin A with hDPPIV based on the X-ray crystal structure. [ABSTRACT FROM AUTHOR]

Retracing human cognitive origins started out at the systems level with the top-down interpretation of archaeological records spanning from man-made artifacts to endocasts of ancient skulls. With emerging evolutionary genetics and organoid technologies, it is now possible to deconstruct evolutionary processes on a molecular/cellular level from the bottom-up by functionally testing archaic alleles in experimental models. The current challenge is to complement these approaches with novel strategies that allow a holistic reconstruction of evolutionary patterns across human cognitive domains. We argue that computational neuroarcheology can provide such a critical mesoscale framework at the brain network-level, linking molecular/cellular (bottom-up) to systems (top-down) level data for the correlative archeology of the human mind. [ABSTRACT FROM AUTHOR]

Advances of in vitro culture models have allowed unprecedented insights into human neurobiology. At the same time genetic screening has matured into a robust and accessible experimental strategy allowing for the simultaneous study of many genes in parallel. The combination of both technologies is a newly emerging tool for neuroscientists, opening the door to identifying causal cell- and tissue-specific developmental and disease mechanisms. However, with complex experimental genetic screening set-ups new challenges in data interpretation and experimental scope arise that require a deep understanding of the benefits and challenges of individual approaches. In this review, we summarize the literature that applies genetic screening to in vitro brain models, compare experimental strengths and weaknesses and point towards future directions of these promising approaches. [ABSTRACT FROM AUTHOR]

Posttranscriptional processes in Bacteria include the association of small regulatory RNAs (sRNA) with a target mRNA. The sRNA/mRNA annealing process is often mediated by an RNA chaperone called Hfq. The functional role of bacterial and eukaryotic Lsm proteins is partially understood, whereas knowledge about archaeal Lsm proteins is scarce. Here, we used the genetically tractable archaeal hyperthermophile Pyrococcus furiosus to identify the protein interaction partners of the archaeal Sm-like proteins (PfuSmAP1) using mass spectrometry and performed a transcriptome-wide binding site analysis of PfuSmAP1. Most of the protein interaction partners we found are part of the RNA homoeostasis network in Archaea including ribosomal proteins, the exosome, RNA-modifying enzymes, but also RNA polymerase subunits, and transcription factors. We show that PfuSmAP1 preferentially binds messenger RNAs and antisense RNAs recognizing a gapped poly(U) sequence with high affinity. Furthermore, we found that SmAP1 co-transcriptionally associates with target RNAs. Our study reveals that in contrast to bacterial Hfq, PfuSmAP1 does not affect the transcriptional activity or the pausing behaviour of archaeal RNA polymerases. We propose that PfuSmAP1 recruits antisense RNAs to target mRNAs and thereby executes its putative regulatory function on the posttranscriptional level. [ABSTRACT FROM AUTHOR]

The distance between CaV2.1 voltage-gated Ca2+ channels and the Ca2+ sensor responsible for vesicle release at presynaptic terminals is critical for determining synaptic strength. Yet, the molecular mechanisms responsible for a loose coupling configuration of CaV2.1 in certain synapses or developmental periods and a tight one in others remain unknown. Here, we examine the nanoscale organization of two CaV2.1 splice isoforms (CaV2.1[EFa] and CaV2.1[EFb]) at presynaptic terminals by superresolution structured illumination microscopy. We find that CaV2.1[EFa] is more tightly co-localized with presynaptic markers than CaV2.1[EFb], suggesting that alternative splicing plays a crucial role in the synaptic organization of CaV2.1 channels. [ABSTRACT FROM AUTHOR]

This study aims to explore the mechanism of microRNA (miR)-101-3p-mediated SOX2/ZIC5 axis in the progression of cisplatin resistance of nasopharyngeal carcinoma (NPC). ZIC5 expression was analyzed with a bioinformatics database and detected in NPC cell lines. Cisplatin-resistant cells (HNE-1/DDP and C666-1/DDP) were transfected with sh-ZIC5, sh-SOX2, sh-SOX2 + pcDNA3.1-ZIC5, or miR-101-3p Agomir + pcDNA3.1-SOX2. MiR-101-3p, SOX2, and ZIC5 expression was assessed after transfection, and cancer associated phenotypes were evaluated after cisplatin treatment. The potential relationships among miR-101-3p, SOX2, and ZIC5 were analyzed. A xenograft mouse model of NPC was established with HNE-1 cells stably transfected or not transfected with oe-ZIC5 and subjected to tail vein injection of miR-101-3p Agomir and intraperitoneal injection of cisplatin. Overexpression of ZIC5 was found in cisplatin-resistant NPC cells. Downregulating ZIC5 in NPC cells decreased cell viability, promoted apoptosis, and reduced cisplatin resistance. SOX2 had a binding site on ZIC5, and SOX2 promoted proliferation, migration, and cisplatin resistance and inhibited cell apoptosis by up-regulating ZIC5. Mechanistically, miR-101-3p was decreased in cisplatin-resistant NPC cells and negatively targeted SOX2. Overexpression of miR-101-3p inhibited tumor growth and cisplatin resistance in xenograft mouse model, which was reversed by ZIC5 overexpression. In conclusion, the miR-101-3p/SOX2/ZIC5 axis was implicated in cancer associated phenotypes and cisplatin resistance in NPC. [ABSTRACT FROM AUTHOR]

Proteolysis is an essential process to maintain cellular homeostasis. One pathway that mediates selective protein degradation and which is in principle conserved throughout the kingdoms of life is the N-degron pathway, formerly called the 'N-end rule'. In the cytosol of eukaryotes and prokaryotes, N-terminal residues can be major determinants of protein stability. While the eukaryotic N-degron pathway depends on the ubiquitin proteasome system, the prokaryotic counterpart is driven by the Clp protease system. Plant chloroplasts also contain such a protease network, which suggests that they might harbor an organelle specific N-degron pathway similar to the prokaryotic one. Recent discoveries indicate that the N-terminal region of proteins affects their stability in chloroplasts and provides support for a Clp-mediated entry point in an N-degron pathway in plastids. This review discusses structure, function and specificity of the chloroplast Clp system, outlines experimental approaches to test for an N-degron pathway in chloroplasts, relates these aspects into general plastid proteostasis and highlights the importance of an understanding of plastid protein turnover. [ABSTRACT FROM AUTHOR]

Classical fluorescence microscopy is a powerful technique to image biological specimen under close-to-native conditions, but light diffraction limits its optical resolution to 200–300 nm-two orders of magnitude worse than the size of biomolecules. Assuming single fluorescent emitters, the final image of the optical system can be described by a convolution with the point spread function (PSF) smearing out details below the size of the PSF. In mathematical terms, fluorescence microscopy produces bandlimited space-continuous images that can be recovered from their spatial samples under the conditions of the classical Shannon-Nyquist theorem. During the past two decades, several single molecule localization techniques have been established and these allow for the determination of molecular positions with sub-pixel accuracy. Without noise, single emitter positions can be recovered precisely – no matter how close they are. We review recent work on the computational resolution limit with a sharp phase transition between two scenarios: 1) where emitters are well-separated with respect to the bandlimit and can be recovered up to the noise level and 2) closely distributed emitters which results in a strong noise amplification in the worst case. We close by discussing additional pitfalls using single molecule localization techniques based on structured illumination. [ABSTRACT FROM AUTHOR]

Tonic current through hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels is influencing neuronal firing properties and channel function is strongly influenced by the brain-specific auxiliary subunit tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b). Since Kv1.2 channels and TRIP8b were also suggested to interact, we assessed brain Kv1.2 mRNA and protein expression as well as the reduction of K+ outward currents by Kv1.2-blocking compounds (Psora-4; tityustoxin-Kα, TsTX-Kα) in different brain areas of TRIP8b-deficient (TRIP8b−/−) compared to wildtype (WT) mice. We found that transcription levels of Kv1.2 channels were not different between genotypes. Furthermore, Kv1.2 current amplitude was not affected upon co-expression with TRIP8b in oocytes. However, Kv1.2 immunofluorescence was stronger in dendritic areas of cortical and hippocampal neurons. Furthermore, the peak net outward current was increased and the inactivation of the Psora-4-sensitive current component was less pronounced in cortical neurons in TRIP8b−/− mice. In current clamp recordings, application of TsTX increased the excitability of thalamocortical (TC) neurons with increased number of elicited action potentials upon step depolarization. We conclude that TRIP8b may not preferentially influence the amplitude of current through Kv1.2 channels but seems to affect current inactivation and channel localization. In TRIP8b−/− a compensatory upregulation of other Kv channels was observed. [ABSTRACT FROM AUTHOR]

Ion channels play an important role for regulation of the exocrine and the endocrine pancreas. This review focuses on the Ca2+-regulated K+ channel KCa3.1, encoded by the KCNN4 gene, which is present in both parts of the pancreas. In the islets of Langerhans, KCa3.1 channels are involved in the regulation of membrane potential oscillations characterizing nutrient-stimulated islet activity. Channel upregulation is induced by gluco- or lipotoxic conditions and might contribute to micro-inflammation and impaired insulin release in type 2 diabetes mellitus as well as to diabetes-associated renal and vascular complications. In the exocrine pancreas KCa3.1 channels are expressed in acinar and ductal cells. They are thought to play a role for anion secretion during digestion but their physiological role has not been fully elucidated yet. Pancreatic carcinoma, especially pancreatic ductal adenocarcinoma (PDAC), is associated with drastic overexpression of KCa3.1. For pharmacological targeting of KCa3.1 channels, we are discussing the possible benefits KCa3.1 channel inhibitors might provide in the context of diabetes mellitus and pancreatic cancer, respectively. We are also giving a perspective for the use of a fluorescently labeled derivative of the KCa3.1 blocker senicapoc as a tool to monitor channel distribution in pancreatic tissue. In summary, modulating KCa3.1 channel activity is a useful strategy for exo-and endocrine pancreatic disease but further studies are needed to evaluate its clinical suitability. [ABSTRACT FROM AUTHOR]

The GluN2C subunit exists predominantly, but not exclusively in NMDA receptors within the cerebellum. Antagonists such as UBP1700 and positive allosteric modulators including PYD-106 and 3-acylamino-2-aminopropionic acid derivatives such as UA3-10 ((R)-2-amino-3-{[5-(2-bromophenyl)thiophen-2-yl]carboxamido}propionic acid) represent promising tool compounds to investigate the role of GluN2C-containing NMDA receptors in the signal transduction in the brain. However, due to its high polarity the bioavailability and CNS penetration of the amino acid UA3-10 are expected to be rather low. Herein, three ester prodrugs 12a–c of the NMDA receptor glycine site agonist UA3-10 were prepared and pharmacokinetically characterized. The esters 12a–c showed higher lipophilicity (higher logD7.4 values) than the acid UA3-10 but almost the same binding at human serum albumin. The acid UA3-10 was rather stable upon incubation with mouse liver microsomes and NADPH, but the esters 12a–c were fast hydrolyzed to afford the acid UA3-10. Incubation with pig liver esterase and mouse serum led to rapid hydrolysis of the esters 12a–c. The isopropyl ester 12c showed a promising logD7.4 value of 3.57 and the highest stability in the presence of pig liver esterase and mouse serum. These results demonstrate that ester prodrugs of UA3-10 can potentially afford improved bioavailability and CNS penetration. [ABSTRACT FROM AUTHOR]

The assembly of the peroxisomal translocon involves the transition of a soluble form of the peroxisomal targeting receptor PEX5 into a membrane-bound form, which becomes an integral membrane component of the import pore for peroxisomal matrix proteins. How this transition occurs is still a mystery. We addressed this question using a artificial horizontal bilayer in combination with fluorescence time-correlated single photon counting (TCSPC) and electrophysiological channel recording. Purified human isoform PEX5L and truncated PEX5L(1–335) lacking the cargo binding domain were selectively labeled with thiol-reactive Atto-dyes. Diffusion coefficients of labeled protein in solution show that PEX5L is monomeric with a rather compact spherical conformation, while the truncated protein appeared in a more extended conformation. Labeled PEX5L and the truncated PEX5L(1–335) bind stably to horizontal bilayer thereby accumulating around 100-fold. The diffusion coefficients of the membrane-bound PEX5L forms are 3–4 times lower than in solution, indicating the formation of larger complexes. Electrophysiological single channel recording shows that membrane-bound labeled and non-labeled PEX5L, but not the truncated PEX5L(1–335), can form ion conducting membrane channels. The data suggest that PEX5L is the pore-forming component of the oligomeric peroxisomal translocon and that spontaneous PEX5L membrane surface binding might be an important step in its assembly. [ABSTRACT FROM AUTHOR]

Oxalyl-CoA synthetase from Saccharomyces cerevisiae is one of the most abundant peroxisomal proteins in yeast and hence has become a model to study peroxisomal translocation. It contains a C-terminal Peroxisome Targeting Signal 1, which however is partly dispensable, suggesting additional receptor bindings sites. To unravel any additional features that may contribute to its capacity to be recognized as peroxisomal target, we determined its assembly and overall architecture by an integrated structural biology approach, including X-ray crystallography, single particle cryo-electron microscopy and small angle X-ray scattering. Surprisingly, it assembles into mixture of concentration-dependent dimers, tetramers and hexamers by dimer self-association. Hexameric particles form an unprecedented asymmetric horseshoe-like arrangement, which considerably differs from symmetric hexameric assembly found in many other protein structures. A single mutation within the self-association interface is sufficient to abolish any higher-level oligomerization, resulting in a homogenous dimeric assembly. The small C-terminal domain of yeast Oxalyl-CoA synthetase is connected by a partly flexible hinge with the large N-terminal domain, which provides the sole basis for oligomeric assembly. Our data provide a basis to mechanistically study peroxisomal translocation of this target. [ABSTRACT FROM AUTHOR]

Heme is an indispensable cofactor for almost all aerobic life, including the human host and many bacterial pathogens. During infection, heme and hemoproteins are the largest source of bioavailable iron, and pathogens have evolved various heme acquisition pathways to satisfy their need for iron and heme. Many of these pathways are regulated transcriptionally by intracellular iron levels, however, host heme availability and intracellular heme levels have also been found to regulate heme uptake in some species. Knowledge of these pathways has helped to uncover not only how these bacteria incorporate host heme into their metabolism but also provided insight into the importance of host heme as a nutrient source during infection. Within this review is covered multiple aspects of the role of heme at the host pathogen interface, including the various routes of heme biosynthesis, how heme is sequestered by the host, and how heme is scavenged by bacterial pathogens. Also discussed is how heme and hemoproteins alter the behavior of the host immune system and bacterial pathogens. Finally, some unanswered questions about the regulation of heme uptake and how host heme is integrated into bacterial metabolism are highlighted. [ABSTRACT FROM AUTHOR]

Heme is a vital cofactor of proteins with roles in oxygen transport (e.g. hemoglobin), storage (e.g. myoglobin), and activation (e.g. P450) as well as electron transfer (e.g. cytochromes) and many other functions. However, its structural and functional role in oxygen sensing proteins differs markedly from that in most other enzymes, where it serves as a catalytic or functional center. This minireview discusses the mechanism of signal transduction in two heme-based oxygen sensors: the histidine kinase AfGcHK and the diguanylate cyclase YddV (EcDosC), both of which feature a heme-binding domain containing a globin fold resembling that of hemoglobin and myoglobin. [ABSTRACT FROM AUTHOR]

Many studies suggest that BACE 1 is the genuine β-secretase; however, this is not undisputed. The wild-type (WT) β-site of the amyloid precursor protein (APP) present in the worldwide population is cleaved very slowly ( kcat/ Km: approx. 50 -1 s-1), while proteases acting on relevant substrates are much more efficient ( kcat/ Km: 104–106 -1 s-1). Knock-out of BACE 1 in mouse markedly reduces Aβ formation. Nevertheless, studies in other systems show that knock-out experiments in rodents and corresponding genetic defects in human may reveal different phenotypes. Considering these issues, we searched for other β-secretase candidate(s), identified cathepsin D, and evaluated properties of cathepsin D related to BACE 1 that were not examined previously. The kinetic constants ( kcat, Km, kcat/ Km) for cleaving peptides with β-sites of the WT or the mutated Swedish families (SW) APP by human BACE 1 and cathepsin D were determined and found to be similar. Western blots reveal that in human brain cathepsin D is approximately 280-fold more abundant than BACE 1. Furthermore, pepstatin A strongly inhibits the cleavage of SW and WT peptides by both brain extracts and cathepsin D, but not by BACE 1. These findings indicate that β-secretase activity observed in brain extracts is mainly due to cathepsin D. Nevertheless, as both BACE 1 and cathepsin D show poor activity towards the WT β-site sequence, it is necessary to continue the search for additional β-secretase candidate(s). [ABSTRACT FROM AUTHOR]

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Keywords: ethinylestradiol; lysyl hydroxylase 2; target identification; yeast three-hybrid screen EN ethinylestradiol lysyl hydroxylase 2 target identification yeast three-hybrid screen 421 431 11 03/11/22 20220301 NES 220301 Introduction Many fundamental processes in biology rely on small ligand-protein interactions which form the basis for pharmacological intervention of human diseases. After washing, bound proteins were eluted with SDS and heat, and analyzed by SDS-PAGE and Western Blotting using a PLOD2 antibody for staining, or a GAL4 antibody for the detection of the GAL4 AD fusion protein from the Y3H vector. Having confirmed that our Y3H setup can indeed detect small molecule-protein interactions, we next wanted to employ this system for the identification of protein binding partners of small molecules out of a pool of proteins. [Extracted from the article]

Periportal and perivenous hepatocytes show zonal heterogeneity in metabolism and signaling. Here, hepatic zonation in mouse liver was analyzed by non-targeted mass spectrometry (MS) and by the antibody-based DigiWest technique, yielding a comprehensive overview of protein expression in periportal and perivenous hepatocytes. Targeted immunoaffinity-based proteomics were used to substantiate findings related to drug metabolism. 165 (MS) and 82 (DigiWest) zonated proteins were identified based on the selected criteria for statistical significance, including 7 (MS) and 43 (DigiWest) proteins not identified as zonated before. New zonated proteins especially comprised kinases and phosphatases related to growth factor-dependent signaling, with mainly periportal localization. Moreover, the mainly perivenous zonation of a large panel of cytochrome P450 enzymes was characterized. DigiWest data were shown to complement the MS results, substantially improving possibilities to bioinformatically identify zonated biological processes. Data mining revealed key regulators and pathways preferentially active in either periportal or perivenous hepatocytes, with β-catenin signaling and nuclear xeno-sensing receptors as the most prominent perivenous regulators, and several kinase- and G-protein-dependent signaling cascades active mainly in periportal hepatocytes. In summary, the present data substantially broaden our knowledge of hepatic zonation in mouse liver at the protein level. [ABSTRACT FROM AUTHOR]

Extensive studies have reported that interaction of α-synuclein amyloid species with neurons is a crucial mechanistic characteristic of Parkinson's disease (PD) and small molecules can downregulate the neurotoxic effects induced by protein aggregation. However, the exact mechanism(s) of these neuroprotective effects by small molecules remain widely unknown. In the present study, α-synuclein samples in the amyloidogenic condition were aged for 120 h with or without different concentrations of mitoquinone (MitoQ) as a quinone derivative compound and the amyloid characteristics and the relevant neurotoxicity were evaluated by Thioflavin T (ThT)/Nile red fluorescence, Congo red absorption, circular dichroism (CD), transmission electron microscopy (TEM), cell viability, lactate dehydrogenase (LDH), reactive oxygen species (ROS), reactive nitrogen species (RNS), malondialdehyde (MDA), superoxide dismutase (SOD), and caspase-9/-3 activity assays. Results clearly showed the capacity of MitoQ on the inhibition of the formation of α-synuclein fibrillation products through modulation of the aggregation pathway by an effect on the kinetic parameters. Also, it was shown that α-synuclein samples aged for 120 h with MitoQ trigger less neurotoxic effects against SH-SY5Y cells than α-synuclein amyloid alone. Indeed, co-incubation of α-synuclein with MitoQ reduced the membrane leakage, oxidative and nitro-oxidative stress, modifications of macromolecules, and apoptosis. [ABSTRACT FROM AUTHOR]

G protein-coupled receptors (GPCRs) modulate a variety of physiological functions and have been proven to be outstanding drug targets. However, approximately one-third of all non-olfactory GPCRs are still orphans in respect to their signal transduction and physiological functions. Receptors of the class of Adhesion GPCRs (aGPCRs) are among these orphan receptors. They are characterized by unique features in their structure and tissue-specific expression, which yields them interesting candidates for deorphanization and testing as potential therapeutic targets. Capable of G-protein coupling and non-G protein-mediated function, aGPCRs may extend our repertoire of influencing physiological function. Besides their described significance in the immune and central nervous systems, growing evidence indicates a high importance of these receptors in metabolic tissue. RNAseq analyses revealed high expression of several aGPCRs in pancreatic islets, adipose tissue, liver, and intestine but also in neurons governing food intake. In this review, we focus on aGPCRs and their function in regulating metabolic pathways. Based on current knowledge, this receptor class represents high potential for future pharmacological approaches addressing obesity and other metabolic diseases. [ABSTRACT FROM AUTHOR]

In a search for anti-inflammatory compounds from fungi inhibiting the promoter activity of the small chemokine CXCL10 (Interferon-inducible protein 10, IP-10) as a pro-inflammatory marker gene, the new dihydroxanthone methyl (1R, 2R)-1,2,8-trihydroxy-6-(hydroxymethyl)-9-oxo-2,9-dihydro-1H-xanthene-1-carboxylate (2) and the previously described dihydroxanthone AGI-B4 (1) were isolated from fermentations of a Diaporthe species. The structures of the compounds were elucidated by a combination of one- and two-dimensional NMR spectroscopy, mass spectrometry, and calculations using density functional theory (DFT). Compounds 1 and 2 inhibited the LPS/IFNγ induced CXCL10 promoter activity in transiently transfected human MonoMac6 cells in a dose-dependent manner with IC50 values of 4.1 µM (±0.2 µM) and 1.0 µM (±0.06 µM) respectively. Moreover, compounds 1 and 2 reduced mRNA levels and synthesis of pro-inflammatory mediators such as cytokines and chemokines in LPS/IFNγ stimulated MonoMac6 cells by interfering with the Stat1 and NFκB pathway. [ABSTRACT FROM AUTHOR]

Acute myeloid leukemia (AML) is a heterogeneous, highly malignant disease of the bone marrow. After decades of slow progress, recent years saw a surge of novel agents for its treatment. The most recent advancement is the registration of the Bcl-2 inhibitor ventoclax in combination with a hypomethylating agent (HMA) in the US and Europe for AML patients not eligible for intensive chemotherapy. Treatment of newly diagnosed AML patients with this combination results in remission rates that so far could only be achieved with intensive treatment. However, not all AML patients respond equally well, and some patients relapse early, while other patients experience longer periods of complete remission. A hallmark of AML is its remarkable genetic, molecular and clinical heterogeneity. Here, we review the current knowledge about molecular features of AML that help estimate the probability of response to venetoclax-containing therapies. In contrast to other newly developed AML therapies that target specific recurrent molecular alterations, it seems so far that responses are not specific for a certain subgroup. One exception is spliceosome mutations, where good response has been observed in clinical trials with venetoclax/azacitidine. These mutations are rather associated with a more unfavorable outcome with chemotherapy. In summary, venetoclax in combination with hypomethylating agents represents a significant novel option for AML patients with various molecular aberrations. Mechanisms of primary and secondary resistance seem to overlap with those towards chemotherapy. [ABSTRACT FROM AUTHOR]

For the maintenance of homeostasis termination of immune reactions is as equally important as their induction. In this scenario regulatory T cells (Treg) play an important role. Accordingly a variety of inflammatory diseases are caused by an impairment of Treg. Hence, it is important to identify triggers by which Treg can be induced and activated, respectively. For quite a long time it is known that ultraviolet radiation can induce Treg which inhibit cutaneous immune reactions including contact hypersensitivity. Since these Treg inhibit in an antigen-specific fashion they may harbor therapeutic potential. However similar Treg can be induced also by other triggers which include vitamin D and antimicrobial peptides. Recently it was discovered that the gut microbiome controls the development of Treg in the intestine. The same may apply for the skin. Short chain fatty acids, microbiota-derived bacterial fermentation products, appear to induce and to activate Treg in the skin. Topical application of short chain fatty acids was shown to inhibit contact hypersensitivity and to reduce inflammation in the murine imiquimod-induced psoriasis-like skin inflammation model. Together, these data indicate that induction and activation of Treg may be a potential therapeutic strategy to treat inflammatory diseases in the future. [ABSTRACT FROM AUTHOR]

COVID-19 primarily affects the respiratory system and may lead to severe systemic complications, such as acute respiratory distress syndrome (ARDS), multiple organ failure, cytokine storm, and thromboembolic events. Depending on the immune status of the affected individual early disease control can be reached by a robust type-I-interferon (type-I-IFN) response restricting viral replication. If type-I-IFN upregulation is impaired, patients develop severe COVID-19 that involves profound alveolitis, endothelitis, complement activation, recruitment of immune cells, as well as immunothrombosis. In patients with proper initial disease control there can be a second flare of type-I-IFN release leading to post-COVID manifestation such as chilblain-like lesions that are characterized by thrombosis of small vessels in addition to an inflammatory infiltrate resembling lupus erythematosus (LE). Mechanistically, SARS-CoV-2 invades pneumocytes and endothelial cells by acting on angiotensin-II-converting enzyme 2 (ACE2). It is hypothesized, that viral uptake might downregulate ACE2 bioavailability and enhance angiotensin-II-derived pro-inflammatory and pro-thrombotic state. Since ACE2 is encoded on the X chromosome these conditions might also be influenced by gender-specific regulation. Taken together, SARS-CoV-2 infection affects the vascular compartment leading to variable thrombogenic or inflammatory response depending on the individual immune response status. [ABSTRACT FROM AUTHOR]

High amounts of glycosaminoglycans (GAG) such as hyaluronan (HA) occur in connective tissues. There is nowadays increasing evidence that a "sulfation code" exists which mediates numerous GAG functions. High molecular weight and inhomogeneity of GAG, however, aggravated detailed studies. Thus, synthetic oligosaccharides were urgently required. We will review here chemoenzymatic and analytic strategies to provide defined sulfated and anomerically modified GAG oligosaccharides of the HA type. Representative studies of protein/GAG interactions by (bio)chemical and biophysical methods are reported yielding novel insights into GAG-protein binding. Finally, the biological conclusions and in vivo applications of defined sulfated GAG oligosaccharides will be discussed. [ABSTRACT FROM AUTHOR]

One hundred fifty years ago, Friedrich Miescher discovered DNA when he isolated "Nuclein"—as he named it—from nuclei of human pus cells. Miescher recognized his isolate as a new type of molecule equal in importance to proteins. He realised that it is an acid of large molecular weight and high phosphorus content. Subsequently, he discovered Nuclein also in the nuclei of other cell types, realised that it chemically defines the nucleus, and speculated on its role in proliferation, heredity and fertilisation. While now universally recognised as the discoverer of DNA, whether Miescher also discovered RNA has not yet been addressed. To determine whether his isolation also yielded RNA, we first reproduced his historic protocols. Our resulting modern Nuclein contained a significant percentage of RNA. Encouraged by this result, we then analysed a sample of Nuclein isolated by Miescher from salmon sperm. Assuming that the RNA present in this sample had degraded to nucleobases, we tested for the presence of uracil in the historic Nuclein. Detection of significant levels of uracil by LC-UV-MS demonstrates that Miescher isolated both forms of nucleic acid—DNA and RNA—and underlines the fundamental nature of his discovery for the field of molecular genetics. [ABSTRACT FROM AUTHOR]

The main objective of structural biology is to model proteins and other biological macromolecules and link the structural information to function and dynamics. The biological functions of protein molecules and nucleic acids are inherently dependent on their conformational dynamics. Imaging of individual molecules and their dynamic characteristics is an ample source of knowledge that brings new insights about mechanisms of action. The atomic-resolution structural information on most of the biomolecules has been solved by biophysical techniques; either by X-ray diffraction in single crystals or by nuclear magnetic resonance (NMR) spectroscopy in solution. Cryo-electron microscopy (cryo-EM) is emerging as a new tool for analysis of a larger macromolecule that couldn't be solved by X-ray crystallography or NMR. Now a day's low-resolution Cryo-EM is used in combination with either X-ray crystallography or NMR. The present review intends to provide updated information on applications like X-ray crystallography, cryo-EM and NMR which can be used independently and/or together in solving structures of biological macromolecules for our full comprehension of their biological mechanisms. [ABSTRACT FROM AUTHOR]

Using results from genome-wide association studies for understanding complex traits is a current challenge. Here we review how genotype data can be used with different machine learning (ML) methods to predict phenotype occurrence and severity from genotype data. We discuss common feature encoding schemes and how studies handle the often small number of samples compared to the huge number of variants. We compare which ML methods are being applied, including recent results using deep neural networks. Further, we review the application of methods for feature explanation and interpretation. [ABSTRACT FROM AUTHOR]

Genome-wide CRISPR screens are becoming more widespread and allow the simultaneous interrogation of thousands of genomic regions. Although recent progress has been made in the analysis of CRISPR screens, it is still an open problem how to interpret CRISPR mutations in non-coding regions of the genome. Most of the tools concentrate on the interpretation of mutations introduced in gene coding regions. We introduce a computational pipeline that uses epigenomic information about regulatory elements for the interpretation of CRISPR mutations in non-coding regions. We illustrate our analysis protocol on the analysis of a genome-wide CRISPR screen in hTERT-RPE1 cells and reveal novel regulatory elements that mediate chemoresistance against doxorubicin in these cells. We infer links to established and to novel chemoresistance genes. Our analysis protocol is general and can be applied on any cell type and with different CRISPR enzymes. [ABSTRACT FROM AUTHOR]

In order to take advantage of the continuously increasing number of transcriptome studies, it is important to develop strategies that integrate multiple expression datasets addressing the same biological question to allow a robust analysis. Here, we propose a meta-analysis framework that integrates enriched pathways identified through the Gene Set Enrichment Analysis (GSEA) approach and calculates for each meta-pathway an empirical p-value. Validation of our approach on benchmark datasets showed comparable or even better performance than existing methods and an increase in robustness with increasing number of integrated datasets. We then applied the meta-analysis framework to 15 functional genomics datasets of physiological and pathological cardiac hypertrophy. Within these datasets we grouped expression sets measured at time points that represent the same hallmarks of heart tissue remodeling ('aggregated time points') and performed meta-analysis on the expression sets assigned to each aggregated time point. To facilitate biological interpretation, results were visualized as gene set enrichment networks. Here, our meta-analysis framework identified well-known biological mechanisms associated with pathological cardiac hypertrophy (e.g., cardiomyocyte apoptosis, cardiac contractile dysfunction, and alteration in energy metabolism). In addition, results highlighted novel, potentially cardioprotective mechanisms in physiological cardiac hypertrophy involving the down-regulation of immune cell response, which are worth further investigation. [ABSTRACT FROM AUTHOR]

Ischaemic heart disease is among the most frequent causes of death. Early detection of myocardial pathologies can increase the benefit of therapy and reduce the number of lethal cases. Presence of myocardial scar is an indicator for developing ischaemic heart disease and can be detected with high diagnostic precision by magnetic resonance imaging. However, magnetic resonance imaging scanners are expensive and of limited availability. It is known that presence of myocardial scar has an impact on the well-established, reasonably low cost, and almost ubiquitously available electrocardiogram. However, this impact is non-specific and often hard to detect by a physician. We present an artificial intelligence based approach — namely a deep learning model — for the prediction of myocardial scar based on an electrocardiogram and additional clinical parameters. The model was trained and evaluated by applying 6-fold cross-validation to a dataset of 12-lead electrocardiogram time series together with clinical parameters. The proposed model for predicting the presence of scar tissue achieved an area under the curve score, sensitivity, specificity, and accuracy of 0.89, 70.0, 84.3, and 78.0%, respectively. This promisingly high diagnostic precision of our electrocardiogram-based deep learning models for myocardial scar detection may support a novel, comprehensible screening method. [ABSTRACT FROM AUTHOR]