New insights into the dihydro-mureidomycin biosynthesis controlled by two unusual proteins in Streptomyces roseosporus

BACKGROUND

Uridyl peptide compounds are renowned as a subclass of nucleoside antibiotics for their highly specific antibacterial activity against Gram-negative bacteria and the unique target of action. We previously activated the biosynthetic gene cluster of a uridyl peptide antibiotic, mureidomycin, in Streptomyces roseosporus NRRL 15998 by introducing an exogenous positive regulator gene ssaA, and the generated strain was designated as Sr-hA. This study aims to further explore mureidomycin analogs from Sr-hA as well as the collaborative roles of two wide-spread genes, SSGG-02980 and SSGG-03002 encoding putative nuclease/phosphatase and oxidoreductase respectively, in mureidomycin diversification.

RESULTS

In order to understand how SSGG-02980 and SSGG-03002 contribute to mureidomycin biosynthesis, the gene disruption mutants and complementary strains were constructed. Mass spectrometry analyses revealed that two series of pairwise mureidomycin analogs were synthesized in Sr-hA with a two-dalton difference in molecular weight for each pair. By disruption of SSGG-03002, only mureidomycins with lower molecular weight (MRDs, 1-6) could be specifically accumulated in the mutant (∆03002-hA), whereas the other series of products with molecular weight plus 2 Da (rMRDs, 1'-6') became dominant in SSGG-02980 disruption mutant (∆02980-hA). Further comprehensive NMR analyses were performed to elucidate the structures, and three MRDs (3, 4, 5) with unsaturated double bond at C5-C6 of uracil group were characterized from ∆03002-hA. In contrast, the paired rMRDs analogs (3', 4', 5') from ∆SSGG-02980 corresponding to 3, 4 and 5 were shown to contain a single bond at this position. The results verified that SSGG-03002 participates in the reduction of uracil ring, whereas SSGG-02980 antagonizes the effect of SSGG-03002, which has been rarely recognized for a phosphatase.

CONCLUSIONS

Overall, this study revealed the key roles of two wide-spread families of enzymes in Streptomyces. Of them, oxidoreductase, SSGG-03002, is involved in dihydro-mureidomycin biosynthesis of S. roseosporus, whereas nuclease/phosphatase, SSGG-02980, has an adverse effect on SSGG-03002. This kind of unusual regulation model between nuclease/phosphatase and oxidoreductase is unprecedented, providing new insights into the biosynthesis of mureidomycins in Streptomyces. The findings would be of significance for structural diversification of more uridyl peptide antibiotics against Gram-negative bacteria.

A Chiral Nanocomplex for Multitarget Therapy to Alleviate Neuropathology and Rescue Alzheimer's Cognitive Deficits

Alzheimer's disease (AD) is a severe neurodegenerative condition characterized by inflammation, beta-amyloid (Aβ) plaques, and neurodegeneration, which currently lack effective treatments. Chiral nanomaterials have emerged as a promising option for treating neurodegenerative disorders due to their high biocompatibility, strong sustained release ability, and specific enantiomer selectivity. The development of a stimulus-responsive chiral nanomaterial, UiO-66-NH2 @l-MoS2 QDs@PA-Ni (MSP-U), for the treatment of AD is reported. MSP-U is found to stimulate neural stem cell (NSCs) differentiation, promote in situ hydrogen (H2 ) production, and clear Aβ plaques. l-MoS2 QDs modified with l-Cysteine (l-Cys) effectively enhance the differentiation of NSCs into neurons through circularly polarized near-infrared radiation. Doped-phytic acid nickel (PA-Ni) improves the activity of l-MoS2 QDs in scavenging reactive oxygen species at the lesion site via photocatalytic H2 production. Loading l-MoS2 QDs with UiO-66 type metal oxide suppresses electron-hole recombination effect, thereby achieving rapid charge separation and improving transport of photogenerated electrons, leading to significantly improved H2 production efficiency. The photothermal effect of MSP-U also clears the generated Aβ plaques. In vivo evaluations show that MSP-U improves spatial cognition and memory, suggesting a promising potential candidate for the treatment of AD using chiral nanomaterials.

MRI Guided Adaptive Radiotherapy (MRgART) in Primary and Metastatic Liver Lesions

PURPOSE/OBJECTIVE(S)

The role of stereotactic body radiotherapy (SBRT) in the management of primary hepatic and metastatic tumors has increased significantly over the past few years. MR-Linac is rapidly gaining evidence in the delivery of ablative doses using MR guided adaptive radiotherapy (MRgART) with improved accuracy and dose coverage to the lesions. We report local control and toxicity of patients with primary and metastatic liver lesions treated with MR guided adaptive SBRT.

MATERIALS/METHODS

All patients were treated with MRgART on the Unity 1.5T MR Linacs at two institutions and consented to the ADAPT-MRL study (1). A 4DCT and MRI with abdominal compression were obtained at simulation and the primary MRI sequence used for online treatment included a T2 3D navigated scan. A balanced turbo field echo (btFFE) 2D cine motion scan was also acquired at every fraction to determine movement of the tumor to aid in internal target volume margin. All plans were treated with SBRT prescribed to 3-5 alternate daily fractions. Acute toxicity was reported according to Common Terminology Criteria for Adverse Events version 5 (CTCAE) v.5. Patient demographics, prescribed dose fractionation, acute toxicity and clinical response at 6 months were analyzed. Clinical response to treatment was measured according to RECIST criteria 1.1.

RESULTS

Between February 2021 to January 2023 a total of 30 patients were treated with 149 fractions to the liver. Patients were majority male (70%) with a median age of 66 (range 36-83). 16 patients were treated for primary hepatocellular carcinoma (HCC) of the liver and 14 patients for metastatic liver lesions. The median prescribed dose was 48 Gy (range 30-50Gy) in median 5 fractions (range (3-5 fractions). All patients completed treatment with no interruptions. The mean time from 'patient setup' to 'beam-off' was 52.6 minutes (range 37-73 minutes). Data on acute toxicity at 3 month follow up was available for 28 patients. Of these patients 7/28 (25%) had grade 1 or 2 toxicity and no >/ = grade 3 toxicity was reported. Clinical response at 6 months was available for 18 patients and showed complete response in 44% (8/18), partial response in 22% (4/18), stable disease in 22% (4/18) and progressive disease in 11.1% (2/18).

CONCLUSION

Our experience on MRgART to the liver has shown good local control and minimal acute toxicity in the treatment of primary and metastatic liver lesions. We continue to collect data on patient reported outcomes, clinical response and toxicity to determine the feasibility and safety of this system.

Safety and Efficacy of Stereotactic Body Radiotherapy for Ultra-Central Thoracic Tumors

PURPOSE/OBJECTIVE(S)

Stereotactic body radiotherapy (SBRT) is increasingly utilized in the management of ultra-central thoracic tumors, although concerns regarding significant toxicity remain. We sought to evaluate the toxicity and efficacy of SBRT to these tumors at our institution.

MATERIALS/METHODS

Patients with ultra-central lung tumors or nodes treated at our institution with SBRT between 2009 and 2019 were retrospectively reviewed. Ultra-central was defined as having the planning target volume (PTV) overlapping or abutting the central bronchial tree and/or esophagus. All SBRT plans were generated with homogenous dose distributions using target coverage objectives of ITV V100% >99%, PTV V95% >99%, and an ideal PTV Dmax <105% (strict <120%). All plans were reviewed in quality assurance rounds by a team of dosimetrists, physicists, and radiation oncologists. The primary endpoint was incidence of severe toxicity (ST), defined as SBRT-related grade ≥3 toxicities, graded using the Common Terminology Criteria for Adverse Events V5.0. Secondary endpoints included local failure (LF), progression-free survival (PFS) and overall survival (OS). Competing risk analysis was used to estimate incidence and predictors of ST and LF, with death as a competing risk. Kaplan-Meier method was used to estimate PFS and OS.

RESULTS

A total of 154 patients who received 162 ultra-central courses of SBRT were included, with a median follow-up of 21.5 months. Treatment intent was most commonly for oligoprogression (46%), oligometastasis (30%), followed by curative (20%). The most frequent tumor histologies were NSCLC (41%) and RCC (26%). SBRT prescription doses ranged from 30-55 Gy in 5 fractions (BED10 range 48-115 Gy). The most common prescription was 50 Gy in 5 fractions (42%). The cumulative incidence of ST was 8.9% at 3-years. The most common ST was pneumonitis (n = 4). Notable toxicities included bronchopleural fistula (n = 2, grade 3 and 4), bronchial stricture (n = 1, grade 3), and esophagitis leading to bleeding (n = 1, grade 4). There were no esophageal strictures or perforations, and no bronchial bleeds. There was 1 possible treatment related death from pneumonitis/pneumonia. Predictors of any ST included increased lung V5 Gy, decreased PTV V95%, and not having prior radiation therapy to the chest. The cumulative incidence of LF was 4.8%, 11% and 14% at 1-, 2-, and 3-years respectively. Predictors of LF included younger age, and greater volume of overlap between the PTV and esophagus. Median PFS was 8.4 months, while median OS was 3.7 years.

CONCLUSION

In one of the largest case series of ultra-central thoracic SBRT reported to date, homogenously prescribed SBRT plans were associated with relatively low rates of ST and LF across a variety of treatment indications. Predictors of ST should be interpreted recognizing the heterogeneity in toxicities observed. Identified predictors of both ST and LF can contribute to future work to optimize the therapeutic ratio in treatment of ultra-central thoracic tumors.

Spatiotemporal dynamics of near-surface ozone concentration and potential source areas in northern China during 2015-2020

Near-surface ozone (O3) pollution has become one of the main factors hampering urban air quality in northern China. However, on a spatiotemporal scale, dynamic transport paths and potential source areas of O3 in northern China are ambiguous. In addition, we suspect that the contribution of transportation activities to urban O3 concentrations developed in northern China may be underestimated. In this study, the HYSPLIT, PSCF, CWT and GTWR model were used to study the transmission paths, potential source areas and driving factors of urban O3 concentration on a spatiotemporal scale. The average annual concentration of surface O3 (the 90th percentile of MDA8) was 172 ± 29 μg/m3 in northern China from 2015 to 2020. In terms of inter-annual variation, the urban O3 concentration increased from 2015 to 2018, and decreased after 2018. On the spatial scale, the areas with high O3 concentration were mainly clustered in industrial cities (Tangshan, Baoding, Shijiazhuang, Xingtai and Handan). During the study period, the area with high O3 concentration in northern China shifted from northwest to southeast. From 2015 to 2020, the influence of long-distance air mass trajectories from Xinjiang and Siberi on airflow transport in Beijing city dominates (78.60%) The average percentage of short-distance transport trajectories from Shandong Peninsula region is about 21.40%. The core potential source areas of O3 pollution shifted from northwest to southeast, but the contribution to O3 pollution in Beijing gradually weakened during the same period. Temperature and relative humidity were the main meteorological driving factors affecting O3 concentration in the study area, while population density, the proportion of secondary industry in GDP, industrial smoke (dust) emissions, and passenger traffic were the main non-meteorological factors. During the period study, the influence of industrial and traffic emissions had a more significant impact on O3 concentration in northern China, which will require that more attention be paid to emission mitigation in the regional industrial and passenger transportation sector, as well as the joint prevention and control of O3 pollution in northern China in the future.

[Landmark vessel in membrane anatomy-based colorectal surgery]

The theory of membrane anatomy has been widely used in the field of colorectal surgery. The key point to perform high quality total mesorectal excision (TME) and complete mesocolic excision (CME) is to identify the correct anatomical plane. Intraoperative identification of the various fasciae and fascial spaces is the key to accessing the correct surgical plane and surgical success. The landmark vessels refer to the small vessels that originate from the original peritoneum on the surface of the abdominal viscera during embryonic development and are produced by the fusion of the fascial space. From the point of view of embryonic development, the abdominopelvic fascial structure is a continuous unit, and the landmark vessels on its surface do not change morphologically with the fusion of fasciae and have a specific pattern. Drawing on previous literature and clinical surgical observations, we believe that tiny vessels could be used to identify various fused fasciae and anatomical planes. This is a specific example of membrane anatomical surgery.

Transmission paths and source areas of near-surface ozone pollution in the Yangtze River delta region, China from 2015 to 2021

Near-ground ozone in the Yangtze River Delta (YRD) region has become one of the main air pollutants that threaten the health of residents. However, to date, the transport behavior and source areas of ozone in the YRD region have not been systematically analyzed. In this study, by combining the ozone observational record with a HYSPLIT (hybrid single-particle Lagrangian integrated trajectory) model, we tried to reveal the spatiotemporal regularity of the airflow transport trajectory of ozone. Spatially, high ozone concentrations mainly clustered in industrial cities and resource-based cities. Temporally, the center of the ozone pollution shifted westward of Nanjing from 2015 to 2021. With the passage of time, the influence of meteorological elements on the ozone concentration in the YRD region gradually weakened. Marine atmosphere had the most significant impact on the transmission path of ozone in Shanghai, of which the trajectory frequency in 2021 accounted for 64.21% of the total frequency. The transmission trajectory of ozone in summer was different from that in other seasons, and its transmission trajectory was mainly composed of four medium-distance transmission paths: North China-Bohai Sea, East China Sea-West Pacific Ocean, Philippine Sea, and South China Sea-South China. The contribution source areas mainly shifted to the southeast, and the emission of pollutants from the Shandong Peninsula, the Korean Peninsula-Japan, and the Philippine Sea-Taiwan area increased the impact of ozone pollution in the Shanghai area from 2019 to 2021. This study identified the regional transport path of ozone in the YRD region and provided a scientific reference for the joint prevention and control of ozone pollution in this area.

An intricate regulation of WblA controlling production of silent tylosin analogues and abolishment of expressible nikkomycin

Genome sequencing has revealed that actinomycetes possess the potential to produce many more secondary metabolites than previously thought. The existing challenge is to devise efficient methods to activate these silent biosynthetic gene clusters (BGCs). In Streptomyces ansochromogenes, disruption of wblA, a pleiotropic regulatory gene, activated the expression of cryptic tylosin analogues and abolished nikkomycin production simultaneously. Overexpressing pathway-specific regulatory genes tylR1 and tylR2 can also trigger the biosynthesis of silent tylosin analogues, in which TylR1 exerted its function via enhancing tylR2 expression. Bacterial one-hybrid system experiments unveiled that WblA directly inhibits the transcription of tylR1 and tylR2 to result in the silence of tylosin analogues BGC. Furthermore, WblA can activate the nikkomycin production through up-regulating the transcription of pleiotropic regulatory gene adpA. More interestingly, AdpA can activate sanG (an activator gene in nikkomycin BGC) but repress wblA. Our studies provide a valuable insight into the complex functions of pleiotropic regulators.

Comparative and Functional Analyses Reveal Conserved and Variable Regulatory Systems That Control Lasalocid Biosynthesis in Different Streptomyces Species

Lasalocid, a representative polyether ionophore, has been successfully applied in veterinary medicine and animal husbandry and also displays promising potential for cancer therapy. Nevertheless, the regulatory system governing lasalocid biosynthesis remains obscure. Here, we identified two conserved (lodR2 and lodR3) and one variable (lodR1, found only in Streptomyces sp. strain FXJ1.172) putative regulatory genes through a comparison of the lasalocid biosynthetic gene cluster (lod) from Streptomyces sp. FXJ1.172 with those (las and lsd) from Streptomyces lasalocidi. Gene disruption experiments demonstrated that both lodR1 and lodR3 positively regulate lasalocid biosynthesis in Streptomyces sp. FXJ1.172, while lodR2 plays a negative regulatory role. To unravel the regulatory mechanism, transcriptional analysis and electrophoretic mobility shift assays (EMSAs) along with footprinting experiments were performed. The results revealed that LodR1 and LodR2 could bind to the intergenic regions of lodR1-lodAB and lodR2-lodED, respectively, thereby repressing the transcription of the lodAB and lodED operons, respectively. The repression of lodAB-lodC by LodR1 likely boosts lasalocid biosynthesis. Furthermore, LodR2 and LodE constitute a repressor-activator system that senses changes in intracellular lasalocid concentrations and coordinates its biosynthesis. LodR3 could directly activate the transcription of key structural genes. Comparative and parallel functional analyses of the homologous genes in S. lasalocidi ATCC 31180T confirmed the conserved roles of lodR2, lodE, and lodR3 in controlling lasalocid biosynthesis. Intriguingly, the variable gene locus lodR1-lodC from Streptomyces sp. FXJ1.172 seems functionally conserved when introduced into S. lasalocidi ATCC 31180T. Overall, our findings demonstrate that lasalocid biosynthesis is tightly controlled by both conserved and variable regulators, providing valuable guidance for further improving lasalocid production. IMPORTANCE Compared to its elaborated biosynthetic pathway, the regulation of lasalocid biosynthesis remains obscure. Here, we characterize the roles of regulatory genes in lasalocid biosynthetic gene clusters of two distinct Streptomyces species and identify a conserved repressor-activator system, LodR2-LodE, which could sense changes in the concentration of lasalocid and coordinate its biosynthesis with self-resistance. Furthermore, in parallel, we verify that the regulatory system identified in a new Streptomyces isolate is valid in the industrial lasalocid producer and thus applicable for the construction of high-yield strains. These findings deepen our understanding of regulatory mechanisms involved in the production of polyether ionophores and provide novel clues for the rational design of industrial strains for scaled-up production.

[Cognition and reflection on the "lateral ligament of rectum"]

As total mesorectal excision (TME) for rectal cancer is widely carried out in China, lateral ligament of rectum, as an important anatomical structure of the lateral rectum with certain anatomical value and clinical significance, has been the focus of attention. In this paper, by comparing and analyzing the characteristics about ligaments of the abdomen and pelvis, reviewing the membrane anatomy and the theory of primitive gut rotation, and combining clinical observations and histological studies, the author came to a conclusion that lateral ligament of rectum does not exist, but is only a relatively dense space on the rectal side accompanied by numerous tiny nerve plexuses and small blood vessels penetrating through it.

Multi-omics Data Reveal the Effect of Sodium Butyrate on Gene Expression and Protein Modification in Streptomyces

Streptomycetes possess numerous gene clusters and the potential to produce a large amount of natural products. Histone deacetylase (HDAC) inhibitors play an important role in the regulation of histone modifications in fungi, but their roles in prokaryotes remain poorly understood. Here, we investigated the global effects of the HDAC inhibitor, sodium butyrate (SB), on marine-derived Streptomycesolivaceus FXJ 8.021, particularly focusing on the activation of secondary metabolite biosynthesis. The antiSMASH analysis revealed 33 secondary metabolite biosynthetic gene clusters (BGCs) in strain FXJ 8.021, among which the silent lobophorin BGC was activated by SB. Transcriptomic data showed that the expression of genes involved in lobophorin biosynthesis (ge00097-ge00139) and CoA-ester formation (e.g., ge02824), as well as the glycolysis/gluconeogenesis pathway (e.g., ge01661), was significantly up-regulated in the presence of SB. Intracellular CoA-ester analysis confirmed that SB triggered the biosynthesis of CoA-ester, thereby increasing the precursor supply for lobophorin biosynthesis. Further acetylomic analysis revealed that the acetylation levels on 218 sites of 190 proteins were up-regulated and those on 411 sites of 310 proteins were down-regulated. These acetylated proteins were particularly enriched in transcriptional and translational machinery components (e.g., elongation factor GE04399), and their correlations with the proteins involved in lobophorin biosynthesis were established by protein-protein interaction network analysis, suggesting that SB might function via a complex hierarchical regulation to activate the expression of lobophorin BGC. These findings provide solid evidence that acetylated proteins triggered by SB could affect the expression of genes involved in the biosynthesis of primary and secondary metabolites in prokaryotes.

A visualization reporter system for characterizing antibiotic biosynthetic gene clusters expression with high-sensitivity

The crisis of antibiotic resistance has become an impending global problem. Genome sequencing reveals that streptomycetes have the potential to produce many more bioactive compounds that may combat the emerging pathogens. The existing challenge is to devise sensitive reporter systems for mining valuable antibiotics. Here, we report a visualization reporter system based on Gram-negative bacterial acyl-homoserine lactone quorum-sensing (VRS-bAHL). AHL synthase gene (cviI) of Chromobacterium violaceum as reporter gene is expressed in Gram-positive Streptomyces to synthesize AHL, which is detected with CV026, an AHL deficient mutant of C. violaceum, via its violacein production upon AHL induction. Validation assays prove that VRS-bAHL can be widely used for characterizing gene expression in Streptomyces. With the guidance of VRS-bAHL, a novel oxazolomycin derivative is discovered to the best of our knowledge. The results demonstrate that VRS-bAHL is a powerful tool for advancing genetic regulation studies and discovering valuable active metabolites in microorganisms.

A quorum sensing based visualization reporter system is presented for the characterization of promoters in Gram-positive bacteria, utilizing violacein production, especially for use in the identification of secondary metabolites.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Spatiotemporal Distribution and Evolution of Digestive Tract Cancer Cases in Lujiang County, China since 2012

This study aims to analyze the spatiotemporal distribution and evolution of digestive tract cancer (DTC) in Lujiang County, China by using the geographic information system technology. Results of this study are expected to provide a scientific basis for effective prevention and control of DTC. The data on DTC cases in Lujiang County, China, were downloaded from the Data Center of the Center for Disease Control and Prevention in Hefei, Anhui Province, China, while the demographic data were sourced from the demographic department in China. Systematic statistical analyses, including the spatial empirical Bayes smoothing, spatial autocorrelation, hotspot statistics, and Kulldorff's retrospective space-time scan, were used to identify the spatial and spatiotemporal clusters of DTC. GM(1,1) and standard deviation ellipses were then applied to predict the future evolution of the spatial pattern of the DTC cases in Lujiang County. The results showed that DTC in Lujiang County had obvious spatiotemporal clustering. The spatial distribution of DTC cases increases gradually from east to west in the county in a stepwise pattern. The peak of DTC cases occurred in 2012-2013, and the high-case spatial clusters were located mainly in the northwest of Lujiang County. At the 99% confidence interval, two spatiotemporal clusters were identified. From 2012 to 2017, the cases of DTC in Lujiang County gradually shifted to the high-incidence area in the northwest, and the spatial distribution range experienced a process of "dispersion-clustering". The cases of DTC in Lujiang County will continue to move to the northwest from 2018 to 2025, and the predicted spatial clustering tends to be more obvious.

Cost-effectiveness analyses of denosumab for osteoporosis: a systematic review

This paper systematically reviewed and assessed all retrievable pharmacoeconomic studies on denosumab for the treatment of osteoporosis. Denosumab was more cost-effective in patients with older age, prior fracture experience, lower BMD T-scores, and more risk factors. ESCEO-IOF guidelines were more applicable to improve the quality of pharmacoeconomic studies in osteoporosis.

INTRODUCTION

There are many pharmacoeconomic studies on denosumab for osteoporosis. However, the corresponding reviews are outdated or incomplete and need to be updated and refined. This article aims to systematically review and evaluate all retrievable pharmacoeconomic studies of denosumab for osteoporosis.

METHODS

A systematic literature search was performed utilizing PubMed, EMBASE(Ovid), Proquest(EconLit), Chongqing VIP, WanFang Database, and Chinese National Knowledge Infrastructure to identify full-text articles published before September 2021. The quality of full-text articles was evaluated by the Consolidated Health Economic Evaluation Reporting Standards(CHEERS) and the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases International Osteoporosis Foundation guideline(ESCEO-IOF).

RESULTS

In total, 21 full-text articles were eligible for inclusion. Denosumab for postmenopausal osteoporosis was not dominant compared to zoledronate and teriparatide. However, denosumab was dominant compared with strontium ranelate, raloxifene, and ibandronate in patients over 65 years. The probabilities of denosumab being cost-effective or dominant were more than 85% compared with no treatment and risedronate in patients aged over 70 years. Compared to alendronate, the highest rate of denosumab dominance occurred in patients aged 65 to 75 years, at about 65%. Most of the articles had higher CHEERS scores than ESCEO-IOF scores (converted into percentages).

CONCLUSIONS

The cost-effectiveness of denosumab for the treatment of osteoporosis was influenced by multiple factors. Generally, denosumab was more cost-effective in patients with older age, prior fracture experience, lower BMD T-scores, and more risk factors. ESCEO-IOF guidelines were more applicable to improve the transparency, generalization, and quality of pharmacoeconomic studies in osteoporosis.

Finely-tuned gamma oscillations: Spectral characteristics and links to dyskinesia

Gamma oscillations comprise a loosely defined, heterogeneous group of functionally different activities between 30 and 100 Hz in the cortical and subcortical local field potential (LFP) of the motor network. Two distinct patterns seem to emerge which are easily conflated: Finely-tuned gamma (FTG) oscillations - a narrowband activity with peaks between 60 and 90 Hz - have been observed in multiple movement disorders and are induced by dopaminergic medication or deep brain stimulation (DBS). FTG has been linked with levodopa or DBS-induced dyskinesias, which makes it a putative biomarker for adaptive DBS. On the other hand, gamma activity can also present as a broad phenomenon (30-100 Hz) in the context of motor activation and dynamic processing. Here, we contrast FTG, either levodopa-induced or DBS-induced, from movement-related broadband gamma synchronisation and further elaborate on the functional role of FTG and its potential implications for adaptive DBS. Given the unclear distinction of FTG and broad gamma in literature, we appeal for more careful separation of the two. To better characterise cortical and subcortical FTG as biomarkers for dyskinesia, their sensitivity and specificity need to be investigated in a large clinical trial.

Repurposing Ivermectin to augment chemotherapy's efficacy in osteosarcoma

BACKGROUND

Osteosarcoma is the most frequent malignant bone malignancy and the current treatments are ineffective. Ivermectin, an anti-protozoal drug, has been shown to have anti-cancer activity. This work investigated the potential of repurposing ivermectin to augment chemotherapy's efficacy in osteosarcoma.

METHODS

Proliferation, migration and apoptosis assays were performed in ivermectin-treated osteosarcoma cells. Combination studies were performed. Osteosarcoma xenograft mouse model was established to investigate the in vivo efficacy of ivermectin. Intracellular reactive oxygen species (ROS) and mitochondrial superoxide, membrane potential, ATP, 8-OHdG level, protein carbonylation and lipid peroxidation were determined after ivermectin treatment.

RESULTS

Ivermectin was effective and acted synergistically with doxorubicin in osteosarcoma cells regardless of cellular origin and genetic profiling. This was achieved through suppressing inhibiting growth and migration, and inducing caspase-dependent apoptosis. Ivermectin also significantly inhibited osteosarcoma growth in vivo and its combination with doxorubicin resulted in much greater efficacy than doxorubicin alone. Importantly, the effective dose of ivermectin was clinically feasible and did not cause significant toxicity in mice. Mechanistical analysis showed that ivermectin induced oxidative stress and damage, and mitochondrial dysfunction.

CONCLUSIONS

Our findings indicate that ivermectin has utility in treating patients with osteosarcoma, especially those resistant to chemotherapy.

Assessment of automated craving across substances and across cultures: stability-analysis of the Craving Automated Scale (CAS)

BACKGROUND

The transition from hedonic to compulsive use in Substance Use Disorders (SUD) is a critical point in SUD progression and hence relevant for assessment and treatment. To measure the habitual patterns of substance consumption, the Craving Automated Scales (CAS) for alcohol (CAS-A), substances (CAS-S) and cigarette smoking (CAS-CS) were developed and introduced to different countries. In this study, we aimed to investigate the structural stability of CAS across substances and cultures.

METHODS

This study analyzed the CAS-scores of a sample of 370 participants in Germany, China and the UK, including 262 opioid-users, 65 smokers and 43 alcohol-users. We performed stability analyses to check the stability (i. e. factorial invariance) of factor solutions. Based on confirmed stability of the general factor (gfactor) solution and the calculations rule obtained in the previous validation of CAS-alcohol (CAS-A), the factor structures of CAS-A, CAS-S and CAS-CS were compared.

RESULTS

The gfactor solutions based on calculations rule shows good stability, with the mean stability coefficients of 0.990 and 0.977 for CAS-S and CAS-CS respectively. The gfactor patterns were similar for CAS-A, CAS-S and CAS-CS, as well as across samples (Germany, China and the UK), with most factor-loadings larger than 0.7. Based on these findings, CAS-S and CAS-CS were also associated with established clinical measures of SUD.

CONCLUSIONS

Our findings suggest the two-gfactor solution based on a proposed calculation rule has a high stability across substances and cultures. This could be in line with common neurobiological mechanisms underlying habitual substance use. Moreover, comparing CAS with established clinical tools suggests that CAS might assess the automated behavior in substance consumption in a more sophisticated way.

Reconstitution of a mini-gene cluster combined with ribosome engineering led to effective enhancement of salinomycin production in Streptomyces albus

Salinomycin, an FDA-approved polyketide drug, was recently identified as a promising anti-tumour and anti-viral lead compound. It is produced by Streptomyces albus, and the biosynthetic gene cluster (sal) spans over 100 kb. The genetic manipulation of large polyketide gene clusters is challenging, and approaches delivering reliable efficiency and accuracy are desired. Herein, a delicate strategy to enhance salinomycin production was devised and evaluated. We reconstructed a minimized sal gene cluster (mini-cluster) on pSET152 including key genes responsible for tailoring modification, antibiotic resistance, positive regulation and precursor supply. These genes were overexpressed under the control of constitutive promoter PkasO* or Pneo . The pks operon was not included in the mini-cluster, but it was upregulated by SalJ activation. After the plasmid pSET152::mini-cluster was introduced into the wild-type strain and a chassis host strain obtained by ribosome engineering, salinomycin production was increased to 2.3-fold and 5.1-fold compared with that of the wild-type strain respectively. Intriguingly, mini-cluster introduction resulted in much higher production than overexpression of the whole sal gene cluster. The findings demonstrated that reconstitution of sal mini-cluster combined with ribosome engineering is an efficient novel approach and may be extended to other large polyketide biosynthesis.

A widespread response of Gram-negative bacterial acyl-homoserine lactone receptors to Gram-positive Streptomyces γ-butyrolactone signaling molecules

Cell-cell communication is critical for bacterial survival in natural habitats, in which miscellaneous regulatory networks are encompassed. However, elucidating the interaction networks of a microbial community has been hindered by the population complexity. This study reveals that γ-butyrolactone (GBL) molecules from Streptomyces species, the major antibiotic producers, can directly bind to the acyl-homoserine lactone (AHL) receptor of Chromobacterium violaceum and influence violacein production controlled by the quorum sensing (QS) system. Subsequently, the widespread responses of more Gram-negative bacterial AHL receptors to Gram-positive Streptomyces signaling molecules are unveiled. Based on the cross-talk between GBL and AHL signaling systems, combinatorial regulatory circuits (CRC) are designed and proved to be workable in Escherichia coli (E. coli). It is significant that the QS systems of Gram-positive and Gram-negative bacteria can be bridged via native Streptomyces signaling molecules. These findings pave a new path for unlocking the comprehensive cell-cell communications in microbial communities and facilitate the exploitation of innovative regulatory elements for synthetic biology.

Cannabis and orofacial pain: a systematic review

The naturally occurring cannabis plant has played an established role in pain management throughout recorded history. However, in recent years, both natural and synthetic cannabis-based products for medicinal use (CBPM) have gained increasing worldwide attention due to growing evidence supporting their use in alleviating chronic inflammatory and neuropathic pain associated with an array of conditions. In view of these products' growing popularity in both the medical and commercial fields, we carried out a systematic review to ascertain the effects of cannabis and its synthetically derived products on orofacial pain and inflammation. The application of topical dermal cannabidiol formulation has shown positive findings such as reducing pain and improving muscle function in patients suffering from myofascial pain. Conversely, two orally-administered synthetic cannabinoid receptor agonists (AZD1940 and GW842166) failed to demonstrate significant analgesic effects following surgical third molar removal. There is a paucity of literature pertaining to the effects of cannabis-based products in the orofacial region; however, there is a wealth of high-quality evidence supporting their use for treating chronic nociceptive and neuropathic pain conditions in other areas. Further research is warranted to explore and substantiate the therapeutic role of CBPMs in the context of orofacial pain and inflammation. As evidence supporting their use expands, healthcare professionals should pay close attention to outcomes and changes to legislation that may impact and potentially benefit their patients.

Letter to the Editor: COVID-19 and Persons with Dementia in Acute Care Settings: How to "EVADE" Challenging Behaviors

The double whammy of dementia and coronavirus disease 2019 (COVID-19) has raised huge concerns for healthcare systems which are already struggling to cope with care demands of persons with dementia (PWD) in non-pandemic times (1). PWD who are admitted to acute care services are particularly vulnerable to behavioural changes and adverse outcomes from delirium (2, 3). During the COVID-19 period, ward relocation is frequently encountered due to COVID-19 screening and segregation; this constant changing of environment and care teams puts PWD at risk of behavioural exacerbations. This is aggravated by restrictive visitor policies in hospitals, depriving PWD of the reassuring presence of family members. Not surprisingly, caring for persons with dementia (PWD) with behavioral issues in acute care settings has become extremely challenging.

MiRNA-300 suppresses proliferation, migration and invasion of non-small cell lung cancer via targeting ETS1

OBJECTIVE

To elucidate the biological function of microRNA-300 (miRNA-300) in influencing the progression of non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

The relative level of miRNA-300 in NSCLC tissues and cells was determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The influences of miRNA-300 on the proliferative, migratory, and invasive potentials of A549 cells were assessed. The binding relationship between miRNA-300 and ETS1 was verified by the Dual-Luciferase Reporter Gene Assay. Finally, the regulatory effect of the interactive miRNA-300 and ETS1 on the progression of NSCLC was identified.

RESULTS

MiRNA-300 was downregulated in NSCLC tissues and cells. The overexpression of miRNA-300 suppressed A549 cells to proliferate, migrate, and invade. MiRNA-300 could bind to ETS1 3'UTR and suppress its level in A549 cells. Notably, the knockdown of miRNA-300 could reverse the regulatory role of ETS1 in the cellular behaviors of NSCLC.

CONCLUSIONS

MiRNA-300 suppresses NSCLC to proliferate, migrate, and invade by targeting ETS1.

Component Optimization of Neomycin Biosynthesis via the Reconstitution of a Combinatorial Mini-Gene-Cluster in Streptomyces fradiae

Neomycin, a multicomponent aminoglycoside antibiotic, is mainly utilized in livestock husbandry and feed additives in animals. The antimicrobial potency of the main product neomycin B is higher than that of its stereoisomer neomycin C. However, the content of neomycin C as an impurity in the high-producing strain is relatively high, and its isolation or removal from neomycin B is quite difficult, which influences the widespread application of neomycin. In this work, the essential genes responsible for neomycin biosynthesis were evaluated and overexpressed to reduce the content of neomycin C. Among them, neoG and neoH are two novel regulatory genes for neomycin biosynthesis, aphA is a resistance gene, neoN encoding a radical SAM-dependent epimerase is responsible for the conversion of neomycin C to B using SAM as the cofactor, and metK is a SAM synthetase coding gene. We demonstrated that the reconstitution and overexpression of a mini-gene-cluster (P_kasO*-neoN-metK-P_kasO*-neoGH-aphA) could effectively reduce the accumulation of neomycin C from 19.1 to 12.7% and simultaneously increase neomycin B by ∼13.1% in the engineered strain Sf/pKCZ04 compared with the wild-type strain (Sf). Real-time quantitative polymerase chain reaction analysis revealed the remarkable up-regulation of the neoE, neoH, neoN, and metK genes situated in the mini-gene-cluster. The findings will pave a new path for component optimization and the large-scale industrial production of significant commercial antibiotics.

Co-expression of a SARP Family Activator ChlF2 and a Type II Thioesterase ChlK Led to High Production of Chlorothricin in Streptomyces antibioticus DSM 40725

Chlorothricin (CHL), produced by Streptomyces antibioticus DSM 40725 (wild-type strain, WT), belongs to a growing family of spirotetronate antibiotics that have biological activities inhibiting pyruvate carboxylase and malate dehydrogenase. ChlF2, a cluster-situated SARP regulator, can activate the transcription of chlJ, chlC3, chlC6, chlE1, chlM, and chlL to control CHL biosynthesis. Co-expression of chlF2 and chlK encoding type II thioesterase in WT strain under the control of P_kan led to high production of chlorothricin by 840% in comparison with that of WT. Since the inhibitory activity of CHL against several Gram-positive bacteria is higher than des-CHL, combinatorial strategies were applied to promote the conversion of des-CHL to CHL. Over-expression of chlB4, encoding a halogenase, combining with the supplementation of sodium chloride led to further 41% increase of CHL production compared to that of F2OE, a chlF2 over-expression strain. These findings provide new insights into the fine-tuned regulation of spirotetronate family of antibiotics and the construction of high-yield engineered strains.

Local field potential activity dynamics in response to deep brain stimulation of the subthalamic nucleus in Parkinson's disease

Local field potentials (LFPs) may afford insight into the mechanisms of action of deep brain stimulation (DBS) and potential feedback signals for adaptive DBS. In Parkinson's disease (PD) DBS of the subthalamic nucleus (STN) suppresses spontaneous activity in the beta band and drives evoked resonant neural activity (ERNA). Here, we investigate how STN LFP activities change over time following the onset and offset of DBS. To this end we recorded LFPs from the STN in 14 PD patients during long (mean: 181.2 s) and short (14.2 s) blocks of continuous stimulation at 130 Hz. LFP activities were evaluated in the temporal and spectral domains. During long stimulation blocks, the frequency and amplitude of the ERNA decreased before reaching a steady state after ~70 s. Maximal ERNA amplitudes diminished over repeated stimulation blocks. Upon DBS cessation, the ERNA was revealed as an under-damped oscillation, and was more marked and lasted longer after short duration stimulation blocks. In contrast, activity in the beta band suppressed within 0.5 s of continuous DBS onset and drifted less over time. Spontaneous activity was also suppressed in the low gamma band, suggesting that the effects of high frequency stimulation on spontaneous oscillations may not be selective for pathological beta activity. High frequency oscillations were present in only six STN recordings before stimulation onset and their frequency was depressed by stimulation. The different dynamics of the ERNA and beta activity with stimulation imply different DBS mechanisms and may impact how these activities may be used in adaptive feedback.

FRI0022 THE ANALYSIS OF THE INVOLVEMENT OF TRANSFORMING-GROWTH INTERACTING FACTOR POLYMORPHISMS IN THE BONE METABOLISM OF RHEUMATOID ARTHRITIS

Background:

Rheumatoid arthritis (RA) is an autoimmune disease that mainly invades synovial membranes and further damage to articular cartilage and bone. The abnormal activation of transforming-growth factor β (TGF-β) in the subchondral bone is related to the onset of RA joint cartilage degeneration and transforming-growth interacting factor (TGIF) is a negative regulator of TGF-β signaling, while there is no literature addressing the relationship between TGIF polymorphisms and the bone metabolism of RA.

Objectives:

The aim of the study was to comprehensively explore the possible association for single nucleotide polymorphisms (SNPs) in the TGIF gene with serum bone metabolism markers and RA susceptibility.

Methods:

Three SNPs within the TGIF gene were genotyped in 155 RA patients and 168 healthy controls by high resolution melting (HRM) analysis in a case-control study. The serum levels of osteocalcin, bone alkaline phosphatase (BALP) and β type I collagen-crosslinked C telopeptide (β-CTX) were detected by electrochemical luminescence in 108 RA patients randomly selected from RA patients group.

Results:

Genotypes and alleles frequency analysis showed rs7362020 was associated with bone erosion in RA (P=0.012, P=0.003, respectively) and individuals carrying T allele for rs7362020 showed a decreased RA risk (OR=0.59, 95% CI = 0.42-0.84; P= 0.003). In the gender-specific analysis, rs73620203 polymorphism was associated with bone erosion of female RA patients (P values of the distribution of genotypes and alleles were 0.022 and 0.006, respectively). In addition, RA patients with CC, CT and TT genotypes at rs73620203 locus had statistically significant differences in serum osteocalcin and BALP (P=0.006, P=0.037, respectively) and the serum levels in TT genotype RA patients were significantly lower than CC and CT genotype RA patients. The serum levels of β-CTX in rs85440 AA genotype male RA patients were significantly higher than female RA patients (P=0.001), while the serum levels of osteocalcin and BALP in genotype AA, AG and GG female and male RA patients were not significantly different (P all>0.05).

Conclusion:

Our study provided the first evidence that rs73620203 is associated with bone erosion of RA and provided new insight into the relationship between three SNPs within TGIF gene and regulation of bone metabolism in RA patients of different genders.

Acknowledgments:

This work was supported by the National Natural Science Foundation of China (Nos. 81772258) and Science and Technology Agency of Sichuan Province (Nos. 2019YFS0310, 2018FZ0106).

Disclosure of Interests:

None declared

[HIV/AIDS related frailty syndrome in the elderly and related research progress]

Frailty syndrome, caused by degenerative changes in the body and the body vulnerability due to a variety of chronic diseases, is associated with adverse outcomes, such as fall, disability and mortality. With the development of antiretroviral therapy, the average life span of HIV/AIDS patients is extended, the number of elderly living with HIV/AIDS has increased, resulting the increase of the incidence of frailty syndrome in this population. The incidence of frailty syndrome in the elderly is associated with HIV infection and adverse reaction of antiretroviral therapy. Early assessment and intervention of frailty syndrome in elderly HIV/AIDS patients can reduce adverse clinical events and improve the quality of life.

Functional demonstration of plant flavonoid carbocations proposed to be involved in the biosynthesis of proanthocyanidins

The plant flavonoid dogma proposes that labile plant flavonoid carbocations (PFCs) play vital roles in the biosynthesis of proanthocyanidins (PAs). However, whether PFCs exist in plants and how PFCs function remain unclear. Here, we report the use of an integrative strategy including enzymatic assays, mutant analysis, metabolic engineering, isotope labeling and metabolic profiling to capture PFCs and demonstrate their functions. In anthocyanidin reductase (ANR) assays, an (-)-epicatechin conjugate was captured in protic polar nucleophilic methanol alone or methanol-HCl extracts. Tandem mass spectrum (MS/MS) analysis characterized this compound as an (-)-epicatechin-4-O-methyl (EOM) ether, which resulted from (-)-epicatechin carbocation and the methyl group of methanol. Acid-based catalysis of procyanidin B2 and B3 produced four compounds, which were annotated as two EOM and two (+)-catechin-4-O-methyl (COM) ethers. Metabolic profiling of seven PA pathway mutants showed an absence or reduction of two EOM ether isomers in seeds. Camellia sinensis ANRa (CsANRa), leucoanthocyanidin reductase c (CsLARc), and CsMYB5b (a transcription factor) were independently overexpressed for successful PA engineering in tobacco. The EOM ether was remarkably increased in CsANRa and CsMYB5b transgenic flowers. Further metabolic profiling for eight green tea tissues revealed two EOM and two COM ethers associated with PA biosynthesis. Moreover, an incubation of (-)-epicatechin or (+)-catechin with epicatechin carbocation in CsANRa transgenic flower extracts formed dimeric procyanidin B1 or B2, demonstrating the role of flavan-3-ol carbocation in the formation of PAs. Taken together, these findings indicated that flavan-3-ol carbocations exist in extracts and are involved in the biosynthesis of PAs of plants.

Important role of a LAL regulator StaR in the staurosporine biosynthesis and high-production of Streptomyces fradiae CGMCC 4.576

Staurosporine, belonging to indolocarbazole compounds, is regarded as an excellent lead compound for synthesizing antitumor agents as a potent inhibitor against various protein kinases. In this study, two separate clusters (cluster A and cluster B), corresponding to biosyntheses of K-252c (staurosporine aglycone) and sugar moiety, were identified in Streptomyces fradiae CGMCC 4.576 and heterologously expressed in Streptomyces coelicolor M1146 separately or together. StaR, a cluster-situated LAL family regulator, activates staurosporine biosynthesis by binding to the promoter regions of staO-staC and staG-staN. The conserved sequences GGGGG and GCGCG were found through gradually truncating promoters of staO and staG, and further determined by mutational experiments. Overexpression of staR with the supplementation of 0.01 g L^-1 FeSO₄ increased staurosporine production to 5.2-fold compared with that of the parental strain Streptomyces fradiae CGMCC 4.576 in GYM medium. Our results provided an approach for improvement of staurosporine production mediated by a positive regulator and established the basis for dissecting the regulatory mechanisms of other indolocarbazole compounds with clinical application value.