Elongasome core proteins and class A PBP1a display zonal, processive movement at the midcell of Streptococcus pneumoniae.

Ovoid-shaped bacteria, such as Streptococcus pneumoniae (pneumococcus), have two spatially separated peptidoglycan (PG) synthase nanomachines that locate zonally to the midcell of dividing cells. The septal PG synthase bPBP2x:FtsW closes the septum of dividing pneumococcal cells, whereas the elongasome located on the outer edge of the septal annulus synthesizes peripheral PG outward. We showed previously by sm-TIRFm that the septal PG synthase moves circumferentially at midcell, driven by PG synthesis and not by FtsZ treadmilling. The pneumococcal elongasome consists of the PG synthase bPBP2b:RodA, regulators MreC, MreD, and RodZ, but not MreB, and genetically associated proteins Class A aPBP1a and muramidase MpgA. Given its zonal location separate from FtsZ, it was of considerable interest to determine the dynamics of proteins in the pneumococcal elongasome. We found that bPBP2b, RodA, and MreC move circumferentially with the same velocities and durations at midcell, driven by PG synthesis. However, outside of the midcell zone, the majority of these elongasome proteins move diffusively over the entire surface of cells. Depletion of MreC resulted in loss of circumferential movement of bPBP2b, and bPBP2b and RodA require each other for localization and circumferential movement. Notably, a fraction of aPBP1a molecules also moved circumferentially at midcell with velocities similar to those of components of the core elongasome, but for shorter durations. Other aPBP1a molecules were static at midcell or diffusing over cell bodies. Last, MpgA displayed nonprocessive, subdiffusive motion that was largely confined to the midcell region and less frequently detected over the cell body.

Massive perturbations to atmospheric sulfur in the aftermath of the Chicxulub impact.

SignificanceSulfur isotopes confirm a key role for atmospheric sulfur gases in climatic cooling, mass extinction, and the demise of dinosaurs and other global biota after the Chicxulub bolide impact at the Cretaceous-Paleogene boundary. The sulfur isotope anomalies are confined to beds containing ejecta and, in the immediately overlying sediments, are temporally unrelated to known episodes of volcanism that also bracket this event, further addressing the controversial role of the Deccan Traps in the extinction.

Two Major Extinction Events in the Evolutionary History of Turtles: One Caused by an Asteroid, the Other by Hominins.

AbstractWe live in a time of accelerated biological extinctions that has the potential to mirror past mass extinction events. However, the rarity of mass extinctions and the restructuring of diversity they cause complicate direct comparisons between the current extinction crisis and earlier events. Among animals, turtles (Testudinata) are one of few groups that have both a rich fossil record and sufficiently stable ecological and functional roles to enable meaningful comparisons between the end-Cretaceous mass extinction (∼66 Ma) and the ongoing wave of extinctions. Here we analyze the fossil record of the entire turtle clade and identify two peaks in extinction rates over their evolutionary history. The first coincides with the Cretaceous-Paleogene transition, reflecting patterns previously reported for other taxa. The second major extinction event started in the Pliocene and continues until now. This peak is detectable only for terrestrial turtles and started much earlier in Africa and Eurasia than elsewhere. On the basis of the timing, geography, and functional group of this extinction event, we postulate a link to co-occurring hominins rather than climate change as the cause. These results lend further support to the view that negative biodiversity impacts were already incurred by our ancestors and related lineages and demonstrate the severity of this continued impact through human activities.

A diagnostic challenge of KIT p.V559D and BRAF p.G469A mutations in a paragastric mass.

A patient with gastrointestinal stroma tumor (GIST) and KIT p.V559D and BRAF p.G469A alterations was referred to our institutional molecular tumor board (MTB) to discuss therapeutic implications. The patient had been diagnosed with B-cell chronic lymphocytic leukemia (CLL) years prior to the MTB presentation. GIST had been diagnosed 1 month earlier. After structured clinical annotation of the molecular alterations and interdisciplinary discussion, we considered BRAF/KIT co-mutation unlikely in a treatment-naïve GIST. Discordant variant allele frequencies furthermore suggested a second malignancy. NGS of a CLL sample revealed the identical class 2 BRAF alteration, thus supporting admixture of CLL cells in the paragastric mass, leading to the detection of 2 alterations. Following the MTB recommendation, the patient received imatinib and had a radiographic response. Structured annotation and interdisciplinary discussion in specialized tumor boards facilitate the clinical management of complex molecular findings. Coexisting malignancies and clonal hematopoiesis warrant consideration in case of complex and uncommon molecular findings.

Convergent and/or parallel evolution of RNA-binding proteins in angiosperms after polyploidization.

Increasing studies suggest that the biased retention of stress-related transcription factors (TFs) after whole-genome duplications (WGDs) could rewire gene transcriptional networks, facilitating plant adaptation to challenging environments. However, the role of posttranscriptional factors (e.g. RNA-binding proteins, RBPs) following WGDs has been largely ignored. Uncovering thousands of RBPs in 21 representative angiosperm species, we integrate genomic, transcriptomic, regulatomic, and paleotemperature datasets to unravel their evolutionary trajectories and roles in adapting to challenging environments. We reveal functional enrichments of RBP genes in stress responses and identify their convergent retention across diverse angiosperms from independent WGDs, coinciding with global cooling periods. Numerous RBP duplicates derived from WGDs are then identified as cold-induced. A significant overlap of 29 orthogroups between WGD-derived and cold-induced RBP genes across diverse angiosperms highlights a correlation between WGD and cold stress. Notably, we unveil an orthogroup (Glycine-rich RNA-binding Proteins 7/8, GRP7/8) and relevant TF duplicates (CCA1/LHY, RVE4/8, CBF2/4, etc.), co-retained in different angiosperms post-WGDs. Finally, we illustrate their roles in rewiring circadian and cold-regulatory networks at both transcriptional and posttranscriptional levels during global cooling. Altogether, we underline the adaptive evolution of RBPs in angiosperms after WGDs during global cooling, improving our understanding of plants surviving periods of environmental turmoil.

FtsA acts through FtsW to promote cell wall synthesis during cell division in Escherichia coli.

In Escherichia coli, FtsQLB is required to recruit the essential septal peptidoglycan (sPG) synthase FtsWI to FtsA, which tethers FtsZ filaments to the membrane. The arrival of FtsN switches FtsQLB in the periplasm and FtsA in the cytoplasm from a recruitment role to active forms that synergize to activate FtsWI. Genetic evidence indicates that the active form of FtsQLB has an altered conformation with an exposed domain of FtsL that acts on FtsI to activate FtsW. However, how FtsA contributes to the activation of FtsW is not clear, as it could promote the conformational change in FtsQLB or act directly on FtsW. Here, we show that the overexpression of an activated FtsA (FtsA*) bypasses FtsQ, indicating it can compensate for FtsQ's recruitment function. Consistent with this, FtsA* also rescued FtsL and FtsB mutants deficient in FtsW recruitment. FtsA* also rescued an FtsL mutant unable to deliver the periplasmic signal from FtsN, consistent with FtsA* acting on FtsW. In support of this, an FtsW mutant was isolated that was rescued by an activated FtsQLB but not by FtsA*, indicating it was specifically defective in activation by FtsA. Our results suggest that in response to FtsN, the active form of FtsA acts on FtsW in the cytoplasm and synergizes with the active form of FtsQLB acting on FtsI in the periplasm to activate FtsWI to carry out sPG synthesis.

Conventional and multi-omics assessments of subacute inhalation toxicity due to propylene glycol and vegetable glycerin aerosol produced by electronic cigarettes.

Propylene glycol (PG) and vegetable glycerin (VG) are the most common solvents used in electronic cigarette liquids. No long-term inhalation toxicity assessments have been performed combining conventional and multi-omics approaches on the potential respiratory effects of the solvents in vivo. In this study, the systemic toxicity of aerosol generated from a ceramic heating coil-based e-cigarette was evaluated. First, the aerosol properties were characterized, including carbonyl emissions, the particle size distribution, and aerosol temperatures. To determine toxicological effects, rats were exposed, through their nose only, to filtered air or a propylene glycol (PG)/ glycerin (VG) (50:50, %W/W) aerosol mixture at the target concentration of 3 mg/L for six hours daily over a continuous 28-day period. Compared with the air group, female rats in the PG/VG group exhibited significantly lower body weights during both the exposure period and recovery period, and this was linked to a reduced food intake. Male rats in the PG/VG group also experienced a significant decline in body weight during the exposure period. Importantly, rats exposed to the PG/VG aerosol showed only minimal biological effects compared to those with only air exposure, with no signs of toxicity. Moreover, the transcriptomic, proteomic, and metabolomic analyses of the rat lung tissues following aerosol exposure revealed a series of candidate pathways linking aerosol inhalation to altered lung functions, especially the inflammatory response and disease. Dysregulated pathways of arachidonic acids, the neuroactive ligand-receptor interaction, and the hematopoietic cell lineage were revealed through integrated multi-omics analysis. Therefore, our integrated multi-omics approach offers novel systemic insights and early evidence of environmental-related health hazards associated with an e-cigarette aerosol using two carrier solvents in a rat model.

Translation and validation of prolonged grief disorder (PG-13) scale in Urdu among bereaved adolescents with intellectual disability.

BACKGROUND: The study aimed to translate and validate the Prolonged Grief Disorder (PG-13) scale from English into Urdu language. This involved examining its psychometric properties, evaluating its factor structure and assessing both convergent and discriminant validity. The study was conducted within the cultural context of Pakistan and focused on the assessment of manifestations of grief, including symptoms of prolonged grief, in adolescents with mild-to-moderate intellectual disability (ID). The PG-13 scale was selected for this study due to its demonstrated accuracy in measuring prolonged grieving symptoms in bereaved population. METHOD: A total of 140 adolescents, aged 10-19 years according to the World Health Organization (WHO) 2018 criteria, were selected from 14 cities in Pakistan. These participants had lost loved ones within the time span of the last 4 years. The WHO (2018) guidelines for translation, adaptation, and validation were followed. RESULTS: The findings suggest that the translated and validated PG-13 scale has adequate psychometric properties, with Cronbach alpha coefficient of .97. Confirmatory factor analysis supports a single-factor structure for the scale, with factor loadings ranging from .80 to .95. CONCLUSION: The PG-13 Urdu version is a reliable and validated scale available for assessing grieving symptoms in the Pakistani context.

DLK1 regulates periodontal inflammation by inhibiting NF-κB p65 and JNK signaling pathways.

The roles and molecular mechanisms of Delta-like 1 (DLK1) in periodontitis remain largely unknown. Here, we investigated the expression of DLK1 and NF-κB p65 in Porphyromonas gingivalis (Pg.)-induced periodontitis in vivo. Periodontal inflammation and alveolar bone resorption were analyzed using western blotting, micro-computed tomography, TRAP staining, immunohistochemistry, and immunofluorescence. Raw246.7 cells were stimulated with 1 µg/ml Porphyromonas gingivalis lipopolysaccharide (Pg.LPS) to assess DLK1 expression in vitro. DLK1 overexpression was achieved, and transfection efficiency was confirmed using western blotting and immunofluorescence. The NF-κB and MAPK pathways were activated by treating cells with 1 µg/ml Pg.LPS to explore related mechanisms. Compared with normal tissues, both DLK1 and NF-κB p65 expression increased in periodontitis gingival tissues. DLK1-positive expression was observed in inflammatory infiltrating cells and osteoclasts in the marginal lacunae of the alveolar bone. DLK1 expression in CD68-positive macrophages was detected by immunofluorescence. However, DLK1 expression in Raw246.7 cells decreased after Pg.LPS stimulation and during osteoclast differentiation. DLK1 levels negatively correlated with TNF-α, IL-1ß, and NFATC1. Increased DLK1 in Raw246.7 cells further inhibited COX2 and iNOS expressions. Mechanistically, DLK1 overexpression down-regulated NF-κB p65 and JNK levels. In summary, these findings suggest that DLK1 overexpression inhibits periodontal inflammation through the NF-κB p65 and JNK pathways. Interventions targeting increased DLK1 levels may have therapeutic implications for periodontitis.

Swedish translation and cultural adaptation of the scored Patient-Generated Subjective Global Assessment (PG-SGA©)-A validated tool for screening and assessing malnutrition in clinical practice and research.

INTRODUCTION: The scored Patient-Generated Subjective Global Assessment (PG-SGA©) is a validated tool for the screening, assessment and monitoring of malnutrition, and triaging of interventions. It contains a patient-generated component and a healthcare professional (HCP)-generated component. AIM: To translate the PG-SGA into Swedish, assess the linguistic and content validity of the Swedish version, and ensure conceptional, semantic and operational equivalence to the original English PG-SGA. METHODS: In line with the methodology used in previously translated and culturally adapted versions, the standardised 10-step process suggested by the International Society for Health Economics and Outcomes Research (ISPOR) was followed. In step 7, a cross-sectional study targeting patients n = 51 and HCPs n = 52 was performed at a university hospital in Sweden. Using separate questionnaires, patients assessed the patient component and HCPs, the professional component regarding perceived comprehensibility and difficulty (linguistic validity). The HCPs also assessed perceived relevance (content validity) of all items on the PG-SGA. Item indices for comprehensibility (I-CI), difficulty (I-DI) and content validity (I-CVI) were calculated and averaged into scale indices (S-CI, S-DI and S-CVI). Cut-off standards for item and scale indices were used as reference. RESULTS: The Swedish version of the PG-SGA rated excellent for comprehensibility (S-CI 0.96) and difficulty (S-DI 0.93) for the patient component. The professional component rated acceptable for comprehensibility (S-CI 0.89) and below acceptable for difficulty (S-DI 0.70), with the physical examination rated most difficult (I-DI 0.39 to 0.69). Content validity for the full Swedish PG-SGA was rated excellent (S-CVI 0.94). CONCLUSION: The patient component was considered clear and easy to complete. The full Swedish PG-SGA was considered relevant by HCPs for screening and assessment of malnutrition. Due to perceived difficulty with the physical examination, training of Swedish HCPs in using the PG-SGA is essential before implementing the professional component into clinical practice or research.

Psychometric properties of the PG-13-R scale to assess prolonged grief disorder among bereaved Iranian adults.

OBJECTIVES: The PG-13-Revised (PG-13-R) is a self-report measure to assess prolonged grief disorder (PGD) in terms of Diagnostic and Statistical Manual of Mental Disorders, fifth revision, Text Revision. This measure has been shown to yield good psychometric properties in Western samples. This study aimed to evaluate the psychometric properties of the Persian PG-13-R. METHODS: Three hundred forty-seven individuals (209 women and 138 men) fully completed the scales. The participants were recruited using convenience sampling. The confirmatory factor analysis (CFA), convergent and divergent validity, and reliability of the Persian version of the PG-13-R were evaluated. RESULTS: CFA results of a unidimensional model support the construct validity of this version of the PG-13-R. The results of this study demonstrated that this version of the PG-13-R has internal consistency reliability (omega coefficient of 0.93), and the test-retest reliability with an interval of 6 weeks was 0.89. The convergent and divergent validity was shown with significant correlations between the PG-13-R and measures of depression, PTSD, functional impairment, and hope. SIGNIFICANCE OF RESULTS: Overall, the Persian version of the PG-13-R showed good psychometric properties in the Iranian population.

Effect of passive versus active abdominal drainage on wound infection after pancreatectomy: A meta-analysis.

Following pancreatic resection, there may be a variety of complications, including wound infection, haemorrhage, and abdominal infection. The placement of drainage channels during operation may decrease the chances of postoperative complications. However, what kind of drainage can decrease the rate of postoperative complications is still a matter of debate. The purpose of this research is to evaluate the efficacy of both active and passive drainage for post-operation wound complications. From the beginning of the database until November 2023, EMBASE, the Cochrane Library and the Pubmed database have been searched. The two authors collected 2524 related studies from 3 data bases for importation into Endnote software, and 8 finished trials were screened against the exclusion criteria. Passive drainage can decrease the incidence of superficial wound infection in postoperative patients with pancreas operation (Odds Ratio [OR], 1.30; 95% CI, 1.06-1.60 p = 0.01); No statistically significant difference was found in the incidence of deep infections among the two groups (OR, 1.51; 95% CI, 0.68-3.36 p = 0.31); No statistical significance was found for the rate of haemorrhage after active drainage on the pancreas compared with that of passive drainage (OR, 0.72; 95% CI, 0.29-1.77 p = 0.47); No statistically significant difference was found in the rate of death after operation for patients who had received a pancreas operation in active or passive drainage (OR, 0.90; 95% CI, 0.57-1.42 p = 0.65); On the basis of existing evidence, the use of passive abdominal drainage reduces postoperative surface wound infections in patients. But there were no statistically significant differences in the risk of severe complications, haemorrhage after surgery, or mortality. However, because of the limited sample size of this meta-analysis, it is necessary to have more high-quality research with a large sample size to confirm the findings.

Rat bronchoalveolar lavage proteome changes following e-cigarette aerosol exposures.

E-cigarette liquids are complex mixtures of chemicals consisting of humectants, such as propylene glycol (PG) and vegetable glycerin (VG), with nicotine or flavorings added. Published literature emphasizes the toxicity of e-cigarette aerosols with flavorings whereas much less attention has been given to the biologic effects of humectants. The purpose of the current study was to provide a comprehensive view of the acute biologic effects of e-cigarette aerosols on rat bronchoalveolar lavage (BAL) using mass spectrometry-based global proteomics. Sprague-Dawley rats were exposed to e-cigarette aerosol for 3 h/day for three consecutive days. Groups included: PG/VG alone, PG/VG + 2.5% nicotine (N), or PG/VG + N + 3.3% vanillin (V). Right lung lobes were lavaged for BAL and supernatants prepared for proteomics. Extracellular BAL S100A9 concentrations and BAL cell staining for citrullinated histone H3 (citH3) were also performed. From global proteomics, ∼2,100 proteins were identified from rat BAL. The greatest change in number of BAL proteins occurred with PG/VG exposures alone compared with controls with biological pathways enriched for acute phase responses, extracellular trap formation, and coagulation. Extracellular BAL S100A9 concentrations and the number of citH3 + BAL cells also increased significantly in PG/VG and PG/VG + 2.5% N. In contrast to PG/VG or PG/VG + N, the addition of vanillin to PG/VG + N increased BAL neutrophilia and downregulated lipid transport proteins. In summary, global proteomics support e-cigarette aerosol exposures to PG/VG alone as having a significant biologic effect on the lung independent of nicotine or flavoring with increased markers of extracellular trap formation.

Treatment of Staphylococcus aureus and Candida albicans polymicrobial biofilms by phloroglucinol-gold nanoparticles.

The co-isolation of Staphylococcus aureus and Candida albicans from host tissues and organs and their in vitro and in vivo interaction studies suggest a synergistic relationship in forming polymicrobial biofilms. In particular, during polymicrobial biofilm formation, S. aureus becomes coated in the extracellular matrix secreted by C. albicans, leading to enhanced resistance to antibiotics. Accordingly, understanding the interactions between S. aureus and C. albicans in polymicrobial biofilms is of utmost importance in establishing treatment strategies for polymicrobial infections. As an alternate technique, nanoparticles were used in this investigation to suppress polymicrobial biofilm. The current study aims to manufacture gold nanoparticles (AuNPs) using phloroglucinol (PG), a natural chemical, and test their inhibitory capabilities against S. aureus and C. albicans biofilms in standard and host-mimicking media (like saliva and sputum). PG-AuNPs have a spherical form with an average size of 46.71 ± 6.40 nm. The minimum inhibitory concentration (MIC) values differed when PG-AuNPs were evaluated in the standard and host-mimicking artificial media. The MIC of PG-AuNPs against S. aureus and C. albicans was 2048 µg/mL in both the standard and artificial sputum media. However, the MIC in saliva was only 128 µg/mL. The initial stage polymicrobial biofilm of S. aureus and C. albicans was dramatically decreased at the sub-MIC of PG-AuNPs in both standard and host-mimicking media. S. aureus and C. albicans mature polymicrobial biofilms were more effectively eliminated by MIC and sub-MIC of PG-AuNPs. This study indicates that PG-AuNPs have the ability to limit the formation of polymicrobial biofilms caused by bacterial and fungal diseases.

Pseudoword spelling: insights into sublexical representations and lexical interactions.

ABSTRACTIn this work we introduce a new tool for measuring English spelling-sound consistency, the PG Toolkit, which we use to conduct detailed analyses of pseudoword spellings that provide new insights into the nature of sublexical and lexical representations. There are several key findings: first, sound-spelling consistency measured at two different "grain sizes", phonographeme and onset/rime, each explained unique variance in pseudoword spelling. Second, lexical skill was more related to pseudoword accuracy at the onset/rime level than at the phonographeme level, and individuals who chose more consistent mappings to spell pseudowords tended to have better lexical skill. Finally, no unique contribution of consistency in the reading direction ("feedback") was found after controlling for consistency in the spelling direction. Taken together, the results validate the various measures provided by the PG Toolkit and establish new evidence that supports an interpretation of sublexical processes as operations over hierarchically-structured representations.

Falsirhodobacter algicola sp. nov., a member of the Rhodobacteraceae isolated from the marine red algae Grateloupia sp.

A Gram-negative, pale yellow-pigmented, non-flagellated, motile, rod-shaped and aerobic bacterium, designated strain PG104T, was isolated from red algae Grateloupia sp. collected from the coastal area of Pohang, Republic of Korea. Growth of strain PG104T was observed at 15-35 °C (optimum, 30 °C), pH 6.0-10.0 (optimum, pH 7.5-8.0) and in the presence of 0-8.0 % (w/v) NaCl (optimum, 5.0 %). The predominant fatty acids included C17 : 0, C18 : 0, 11-methyl C18 : 1 ω7c and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and the major respiratory quinone was Q-10. Polar lipids included phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified lipid and one unidentified aminolipid. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain PG104T formed a phylogenetic lineage with members of the genus Falsirhodobacter and exhibited 16S rRNA gene sequence similarities of 97.1 and 96.6 % to Falsirhodobacter deserti W402T and Falsirhodobacter halotolerans JA744T, respectively. The complete genome of strain PG104T consisted of a single circular chromosome of approximately 2.8 Mbp with five plasmids. Based on polyphasic taxonomic data, strain PG104T represents a novel species in the genus Falsirhodobacter, for which the name Falsirhodobacter algicola sp. nov. is proposed. The type strain of Falsirhodobacter algicola is PG104T (=KCTC 82230T=JCM 34380T).

No phylogenetic evidence for angiosperm mass extinction at the Cretaceous-Palaeogene (K-Pg) boundary.

The Cretaceous-Palaeogene mass extinction event (K-Pg) witnessed upwards of 75% of animal species going extinct, most notably among these are the non-avian dinosaurs. A major question in macroevolution is whether this extinction event influenced the rise of flowering plants (angiosperms). The fossil record suggests that the K-Pg event had a strong regional impact on angiosperms with up to 75% species extinctions, but only had a minor impact on the extinction rates of major lineages (families and orders). Phylogenetic evidence for angiosperm extinction dynamics through time remains unexplored. By analysing two angiosperm mega-phylogenies containing approximately 32 000-73 000 extant species, here we show relatively constant extinction rates throughout geological time and no evidence for a mass extinction at the K-Pg boundary. Despite high species-level extinction observed in the fossil record, our results support the macroevolutionary resilience of angiosperms to the K-Pg mass extinction event via survival of higher lineages.

Reprogramming of the heavy-chain CDR3 regions of a human antibody repertoire.

B cells have been engineered ex vivo to express an HIV-1 broadly neutralizing antibody (bNAb). B cell reprograming may be scientifically and therapeutically useful, but current approaches limit B cell repertoire diversity and disrupt the organization of the heavy-chain locus. A more diverse and physiologic B cell repertoire targeting a key HIV-1 epitope could facilitate evaluation of vaccines designed to elicit bNAbs, help identify more potent and bioavailable bNAb variants, or directly enhance viral control in vivo. Here we address the challenges of generating such a repertoire by replacing the heavy-chain CDR3 (HCDR3) regions of primary human B cells. To do so, we identified and utilized an uncharacterized Cas12a ortholog that recognizes PAM motifs present in human JH genes. We also optimized the design of 200 nucleotide homology-directed repair templates (HDRT) by minimizing the required 3'-5' deletion of the HDRT-complementary strand. Using these techniques, we edited primary human B cells to express a hemagglutinin epitope tag and the HCDR3 regions of the bNAbs PG9 and PG16. Those edited with bNAb HCDR3 efficiently bound trimeric HIV-1 antigens, implying they could affinity mature in vivo in response to the same antigens. This approach generates diverse B cell repertoires recognizing a key HIV-1 neutralizing epitope.

PG545 Prevents Osteoarthritis Development by Regulating PI3K/AKT/mTOR Signaling and Activating Chondrocyte Autophagy.

INTRODUCTION: Osteoarthritis (OA) is a degenerative disease common in the elderly and is characterized by joint pain, swelling, and restricted movement. In recent years, heparanase has been reported to play an important role in the development of osteoarthritic cartilage. PG545 is a heparan sulfate mimetic with heparanase inhibitory activity. In this study, the therapeutic effects and possible mechanisms of PG545 were investigated in a chondrocyte injury model induced by interleukin-1ß (IL -1ß). METHODS: Following treatment with PG545 or the autophagy inhibitor 3-methyladenine (3-MA), chondrocyte viability was detected using Cell Counting Kit-8 and fluorescein diacetate/propidium iodide double staining. The apoptosis rate of chondrocytes was determined by flow cytometry. Expression of light chain 3 and P62 was monitored by immunofluorescence labeling. Western blot, lentivirus infection with red fluorescent protein and green fluorescent protein, and quantitative real-time polymerase chain reaction were used to determine the expression levels of chondrocyte markers, apoptosis-related factors, autophagy proteins, and key proteins of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway. The expression and activity of stress-specific enzymes such as malondialdehyde, superoxide dismutase, and catalase (CAT) were investigated. Chondrocytes with ATG5 knockdown were used to investigate the relationship between the therapeutic effect of PG545 and autophagy. The therapeutic effect of PG545 was verified in vivo. RESULTS: PG545 had a significant protective effect on chondrocytes by reducing oxidative stress, apoptosis, and degradation of chondrocytes and increasing chondrocyte proliferation. PG545 was effective in inducing autophagy in IL-1ß-treated cells, while 3-MA attenuated the effect. The PI3K/Akt/mTOR pathway may be involved in the promotion of autophagy and OA treatment by PG545. CONCLUSION: PG545 was able to restore impaired autophagy and autophagic flux via the PI3K/Akt/mTOR pathway, thereby delaying the progression of OA, suggesting that PG545 may be a novel therapeutic approach for OA.

Propylene glycol, skin sensitisation and allergic contact dermatitis: A scientific and regulatory conundrum.

Propylene glycol (PG) has widespread use in pharmaceuticals, cosmetics, fragrances and personal care products. PG is not classified as hazardous under the Globally Harmonised System of Classification and Labelling of Chemicals (GHS) but poses an intriguing scientific and regulatory conundrum with respect to allergic contact dermatitis (ACD), the uncertainty being whether and to what extent PG has the potential to induce skin sensitisation. In this article we review the results of predictive tests for skin sensitisation with PG, and clinical evidence for ACD. Patch testing in humans points to PG having the potential to be a weak allergen under certain conditions, and an uncommon cause of ACD in subjects without underlying/pre-disposing skin conditions. In clear contrast PG is negative in predictive toxicology tests for skin sensitisation, including guinea pig and mouse models (e.g. local lymph node assay), validated in vitro test methods that measure various key events in the pathway leading to skin sensitisation, and predictive methods in humans (Human Repeat Insult Patch and Human Maximisation Tests). We here explore the possible scientific basis for this intriguing inconsistency, recognising there are arguably no known contact allergens that are universally negative in, in vitro, animal and human predictive tests methods.