Aim
To examine the role of palmitic acid in lipopolysaccharide (LPS)‐stimulated chemotaxis of macrophages and the potential contribution of saturated fatty acid in signalling during the pathogenesis ...of apical periodontitis.
Methodology
J774, a mouse macrophage cell line, was used in the experiments. After treatment with LPS, proteolytic maturation of sterol regulatory element‐binding protein‐1c (SREBP‐1c) and expression of fatty acid synthase (FASN) were examined by Western analysis. Levels of palmitic acid were measured by reverse phase‐high performance liquid chromatography‐mass spectrometry. Knockdown of SREBP‐1c and FASN was accomplished by small interfering RNA technology. Secretion of CC‐chemokine ligand 2 (CCL2) and cellular chemotaxis were assessed by enzyme‐linked immunosorbent assay and transwell migration assay, respectively. Sulfo‐N‐succinimidyl oleate (SSO) treatment was used to inhibit fatty acid signalling in vitro and also in a rat model of apical periodontitis. All data were first subjected to Levene’s test. In vitro data were then analysed using ANOVA followed by Tukey’s multiple comparison test. Data from animal experiments were analysed by independent t‐tests. The significant level was set at 0.05.
Results
LPS stimulated proteolytic maturation of SREBP‐1c and FASN expression in macrophages and significantly enhanced palmitic acid synthesis (P < 0.05). Knockdown of SREBP‐1c attenuated LPS‐enhanced FASN expression. Knockdown of FASN significantly suppressed LPS‐enhanced palmitic acid synthesis (P < 0.05). LPS and exogenous palmitic acid significantly enhanced CCL2 secretion and macrophage chemotaxis (all P < 0.05). Inhibition of FASN expression significantly alleviated LPS‐augmented CCL2 secretion (P < 0.05). SSO significantly suppressed CCL2 secretion and macrophage chemotaxis augmented by LPS and palmitic acid (all P < 0.05). In a rat model of induced apical periodontitis, SSO treatment significantly attenuated progression of apical periodontitis and macrophage recruitment (all P < 0.05).
Conclusions
LPS/SREBP‐1c/FASN/palmitic acid signalling contributed to tissue destruction caused by bacterial infection. Modulation of lipid metabolism and signalling may be helpful for the management of apical periodontitis.
Summary
Background
Acral melanoma (AM) is the most common histopathological subtype of malignant melanoma in Asians. However, differences in the mutational profiles underlying AM and nonacral ...cutaneous melanoma (NAM) in Asians are not well understood.
Objectives
To augment the understanding of the prevalence, patterns and associations of various mutations between different subtypes of melanoma.
Methods
We performed comprehensive genomic profiling of 409 cancer‐associated genes, using next‐generation sequencing, in 66 primary melanomas comprised of 45 AMs and 21 NAMs.
Results
Most of the AMs (n = 27/45; 60%), but only five of 21 (24%) NAMs, were triple wild‐type (triple‐WT) tumours. Compared with AMs, NAMs exhibited a significantly higher frequency of BRAF mutations. The frequencies of NRAS/KRAS mutations, cell‐cycle aberrations, copy number gains in BIRC2, BIRC3 and BIRC5, and gains of receptor tyrosine kinase genes were significantly higher in AMs. Ulceration was found at significantly higher rates in the AMs and NAMs with cell‐cycle aberrations and gains of receptor tyrosine kinase genes. Notably, cell‐cycle aberrations and copy number gains in BIRC2, BIRC3 and BIRC5 were significantly associated with poor melanoma‐specific survival in the 66 patients with melanoma and especially in the 45 patients with AM. Multivariate analysis showed that lymph node metastasis and cell‐cycle aberrations were independent prognostic factors of melanoma‐specific survival.
Conclusions
This study strengthens our understanding of the patterns and clinical associations of oncogenic mutations in AMs and NAMs in Asians.
What's already known about this topic?
Mutation frequencies of driver genes vary between melanoma subtypes.
Acral melanoma is the most common subtype of melanoma in Asians.
KIT mutations and copy number variations occur more frequently in the acral subtype of melanoma than in the nonacral subtype
What does this study add?
NRAS/KRAS mutations, cell‐cycle aberrations, copy number gains in BIRC2, BIRC3 and BIRC5, and amplifications of receptor tyrosine kinase genes were significantly enriched in acral melanoma and could be potential targets for treatment.
Melanomas with cell‐cycle aberrations and gains in receptor tyrosine kinase genes were significantly more likely to contain ulceration.
What is the translational message?
Cell‐cycle aberrations and copy number gains in BIRC2, BIRC3 and BIRC5 were significantly associated with poor melanoma‐specific survival.
These observations should be explored further for future drug development.
Linked Comment: Johansson. Br J Dermatol 2020; 182:1085.
Plain language summary available online
Abstract Valproic acid (VPA), a widely prescribed drug for seizures and bipolar disorder, has been shown to be an inhibitor of histone deacetylase (HDAC). Our previous study has demonstrated that VPA ...pretreatment reduces lipopolysaccharide (LPS)-induced dopaminergic (DA) neurotoxicity through the inhibition of microglia over-activation. The aim of this study was to determine the mechanism underlying VPA-induced attenuation of microglia over-activation using rodent primary neuron/glia or enriched glia cultures. Other histone deacetylase inhibitors (HDACIs) were compared with VPA for their effects on microglial activity. We found that VPA induced apoptosis of microglia cells in a time- and concentration-dependent manner. VPA-treated microglial cells showed typical apoptotic hallmarks including phosphatidylserine externalization, chromatin condensation and DNA fragmentation. Further studies revealed that trichostatin A (TSA) and sodium butyrate (SB), two structurally dissimilar HDACIs, also induced microglial apoptosis. The apoptosis of microglia was accompanied by the disruption of mitochondrial membrane potential and the enhancement of acetylation levels of the histone H3 protein. Moreover, pretreatment with SB or TSA caused a robust decrease in LPS-induced pro-inflammatory responses and protected DA neurons from damage in mesencephalic neuron–glia cultures. Taken together, our results shed light on a novel mechanism whereby HDACIs induce neuroprotection and underscore the potential utility of HDACIs in preventing inflammation-related neurodegenerative disorders such as Parkinson’s disease.
Penicillium is a diverse genus occurring worldwide and its species play important roles as decomposers of organic materials and cause destructive rots in the food industry where they produce a wide ...range of mycotoxins. Other species are considered enzyme factories or are common indoor air allergens. Although DNA sequences are essential for robust identification of Penicillium species, there is currently no comprehensive, verified reference database for the genus. To coincide with the move to one fungus one name in the International Code of Nomenclature for algae, fungi and plants, the generic concept of Penicillium was re-defined to accommodate species from other genera, such as Chromocleista, Eladia, Eupenicillium, Torulomyces and Thysanophora, which together comprise a large monophyletic clade. As a result of this, and the many new species described in recent years, it was necessary to update the list of accepted species in Penicillium. The genus currently contains 354 accepted species, including new combinations for Aspergillus crystallinus, A. malodoratus and A. paradoxus, which belong to Penicillium section Paradoxa. To add to the taxonomic value of the list, we also provide information on each accepted species MycoBank number, living ex-type strains and provide GenBank accession numbers to ITS, β-tubulin, calmodulin and RPB2 sequences, thereby supplying a verified set of sequences for each species of the genus. In addition to the nomenclatural list, we recommend a standard working method for species descriptions and identifications to be adopted by laboratories working on this genus.
The study of protein-protein interactions (PPIs) can be very important for the understanding of biological cellular functions. However, detecting PPIs in the laboratories are both time-consuming and ...expensive. For this reason, there has been much recent effort to develop techniques for computational prediction of PPIs as this can complement laboratory procedures and provide an inexpensive way of predicting the most likely set of interactions at the entire proteome scale. Although much progress has already been achieved in this direction, the problem is still far from being solved. More effective approaches are still required to overcome the limitations of the current ones. In this study, a novel Multi-scale Local Descriptor (MLD) feature representation scheme is proposed to extract features from a protein sequence. This scheme can capture multi-scale local information by varying the length of protein-sequence segments. Based on the MLD, an ensemble learning method, the Random Forest (RF) method, is used as classifier. The MLD feature representation scheme facilitates the mining of interaction information from multi-scale continuous amino acid segments, making it easier to capture multiple overlapping continuous binding patterns within a protein sequence. When the proposed method is tested with the PPI data of Saccharomyces cerevisiae, it achieves a prediction accuracy of 94.72% with 94.34% sensitivity at the precision of 98.91%. Extensive experiments are performed to compare our method with existing sequence-based method. Experimental results show that the performance of our predictor is better than several other state-of-the-art predictors also with the H. pylori dataset. The reason why such good results are achieved can largely be credited to the learning capabilities of the RF model and the novel MLD feature representation scheme. The experiment results show that the proposed approach can be very promising for predicting PPIs and can be a useful tool for future proteomic studies.
Quantum computing can become scalable through error correction, but logical error rates only decrease with system size when physical errors are sufficiently uncorrelated. During computation, unused ...high energy levels of the qubits can become excited, creating leakage states that are long-lived and mobile. Particularly for superconducting transmon qubits, this leakage opens a path to errors that are correlated in space and time. Here, we report a reset protocol that returns a qubit to the ground state from all relevant higher level states. We test its performance with the bit-flip stabilizer code, a simplified version of the surface code for quantum error correction. We investigate the accumulation and dynamics of leakage during error correction. Using this protocol, we find lower rates of logical errors and an improved scaling and stability of error suppression with increasing qubit number. This demonstration provides a key step on the path towards scalable quantum computing.
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