DePARylation is critical for S phase progression and cell survival

Poly(ADP-ribose)ylation or PARylation by PAR polymerase 1 (PARP1) and dePARylation by poly(ADP-ribose) glycohydrolase (PARG) are equally important for the dynamic regulation of DNA damage response. PARG, the most active dePARylation enzyme, is recruited to sites of DNA damage via pADPr-dependent and PCNA-dependent mechanisms. Targeting dePARylation is considered an alternative strategy to overcome PARP inhibitor resistance. However, precisely how dePARylation functions in normal unperturbed cells remains elusive. To address this challenge, we conducted multiple CRISPR screens and revealed that dePARylation of S phase pADPr by PARG is essential for cell viability. Loss of dePARylation activity initially induced S-phase-specific pADPr signaling, which resulted from unligated Okazaki fragments and eventually led to uncontrolled pADPr accumulation and PARP1/2-dependent cytotoxicity. Moreover, we demonstrated that proteins involved in Okazaki fragment ligation and/or base excision repair regulate pADPr signaling and cell death induced by PARG inhibition. In addition, we determined that PARG expression is critical for cellular sensitivity to PARG inhibition. Additionally, we revealed that PARG is essential for cell survival by suppressing pADPr. Collectively, our data not only identify an essential role for PARG in normal proliferating cells but also provide a potential biomarker for the further development of PARG inhibitors in cancer therapy.

Genome-wide CRISPR screen reveals the synthetic lethality between BCL2L1 inhibition and radiotherapy

Radiation therapy (RT) is one of the most commonly used anticancer therapies. However, the landscape of cellular response to irradiation, especially to a single high-dose irradiation, remains largely unknown. In this study, we performed a whole-genome CRISPR loss-of-function screen and revealed temporal inherent and acquired responses to RT. Specifically, we found that loss of the IL1R1 pathway led to cellular resistance to RT. This is in part because of the involvement of radiation-induced IL1R1-dependent transcriptional regulation, which relies on the NF-κB pathway. Moreover, the mitochondrial anti-apoptotic pathway, particularly the BCL2L1 gene, is crucially important for cell survival after radiation. BCL2L1 inhibition combined with RT dramatically impeded tumor growth in several breast cancer cell lines and syngeneic models. Taken together, our results suggest that the combination of an apoptosis inhibitor such as a BCL2L1 inhibitor with RT may represent a promising anticancer strategy for solid cancers including breast cancer.

DePARylation is critical for S phase progression and cell survival

Poly(ADP-ribose)ylation or PARylation by PAR polymerase 1 (PARP1) and dePARylation by poly(ADP-ribose) glycohydrolase (PARG) are equally important for the dynamic regulation of DNA damage response. PARG, the most active dePARylation enzyme, is recruited to sites of DNA damage via pADPr-dependent and PCNA-dependent mechanisms. Targeting dePARylation is considered an alternative strategy to overcome PARP inhibitor resistance. However, precisely how dePARylation functions in normal unperturbed cells remains elusive. To address this challenge, we conducted multiple CRISPR screens and revealed that dePARylation of S phase pADPr by PARG is essential for cell viability. Loss of dePARylation activity initially induced S phase-specific pADPr signaling, which resulted from unligated Okazaki fragments and eventually led to uncontrolled pADPr accumulation and PARP1/2-dependent cytotoxicity. Moreover, we demonstrated that proteins involved in Okazaki fragment ligation and/or base excision repair regulate pADPr signaling and cell death induced by PARG inhibition. In addition, we determined that PARG expression is critical for cellular sensitivity to PARG inhibition. Additionally, we revealed that PARG is essential for cell survival by suppressing pADPr. Collectively, our data not only identify an essential role for PARG in normal proliferating cells but also provide a potential biomarker for the further development of PARG inhibitors in cancer therapy.

Copy Number Alterations Predict Development of OSCC from Oral Leukoplakia

Oral leukoplakia (OLK) is a common type of potentially malignant disorder. Early identification of the malignancy potential leads to a better management of OLK and prediction of development of oral squamous cell carcinoma (OSCC). However, there has been no effective biomarker to assess the risk of malignancy in OLK. Genomic copy number alteration (CNA) is a complex chromosomal structural variation in the genome and has been identified as a potential biomarker in multiple cancers. This study aimed to develop a predictive model for the malignant transformation risk of OLK by copy number analysis. A total of 431 OLK samples with long-term follow-up (median follow-up of 67 mo) from multiple academic centers were analyzed for CNAs. CNA events increased with the severity of hyperplasia, mild dysplasia, moderate dysplasia, and severe dysplasia. More CNA events were present in patients with OLK who later developed OSCC than in those with OLK who did not. By multivariate Cox regression analysis, the OLK of the CNA scorehigh group showed an increased risk of malignant transformation than the CNA scorelow group (P < 0.001). A CNA score model was developed to accurately predict the prognosis (area under the receiver operating characteristic curve [AUC] = 0.879; 95% confidence interval [CI], 0.799-0.959) and was validated using data from 2 external centers (AUC = 0.836, 95% CI, 0.683-0.989; AUC = 0.876, 95% CI, 0.682-1.000), and all of them showed better prediction performances than histopathological grade in assessing the transformation risk of OLK. Furthermore, we performed CNA models among 4 subgroups of OLK with hyperplasia, mild dysplasia, moderate dysplasia, and severe dysplasia and found that CNA score can accurately predict malignant transformation of different subgroups. CNA score may be a useful biomarker to predict malignant transformation of OLK. Subtyping of OLK by the CNA score could contribute to better management of OLK and predicting development of OSCC.

RAD54L2-mediated DNA damage avoidance pathway specifically preserves genome integrity in response to topoisomerase 2 poisons

Type II topoisomerases (TOP2) form transient TOP2 cleavage complexes (TOP2ccs) during their catalytic cycle to relieve topological stress. TOP2ccs are covalently linked TOP2-DNA intermediates that are reversible but can be trapped by TOP2 poisons. Trapped TOP2ccs block transactions on DNA and generate genotoxic stress, which are the mechanisms of action of TOP2 poisons. How cells avoid TOP2cc accumulation remains largely unknown. In this study, we uncovered RAD54 like 2 (RAD54L2) as a key factor that mediates a TOP2-specific DNA damage avoidance pathway. RAD54L2 deficiency conferred unique sensitivity to treatment with TOP2 poisons. RAD54L2 interacted with TOP2A/TOP2B and ZATT/ZNF451 and promoted the turnover of TOP2 from DNA with or without TOP2 poisons. Additionally, inhibition of proteasome activity enhanced the chromatin binding of RAD54L2, which in turn led to the removal of TOP2 from chromatin. In conclusion, we propose that RAD54L2-mediated TOP2 turnover is critically important for the avoidance of potential TOP2-linked DNA damage under physiological conditions and in response to TOP2 poisons.

CRISPR/Cas9-Mediated Genome Editing in Cancer Therapy

The Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system, an RNA-based adaptive immune system found in bacteria and archaea, has catalyzed the development and application of a new generation of gene editing tools. Numerous studies have shown that this system can precisely target a wide range of human genes, including those associated with diseases such as cancer. In cancer research, the intricate genetic mutations in tumors have promoted extensive utilization of the CRISPR/Cas9 system due to its efficient and accurate gene editing capabilities. This includes improvements in Chimeric Antigen Receptor (CAR)-T-cell therapy, the establishment of tumor models, and gene and drug target screening. Such progress has propelled the investigation of cancer molecular mechanisms and the advancement of precision medicine. However, the therapeutic potential of genome editing remains underexplored, and lingering challenges could elevate the risk of additional genetic mutations. Here, we elucidate the fundamental principles of CRISPR/Cas9 gene editing and its practical applications in tumor research. We also briefly discuss the primary challenges faced by CRISPR technology and existing solutions, intending to enhance the efficacy of this gene editing therapy and shed light on the underlying mechanisms of tumors.

Ultrasonography for confirmation of emergency department endotracheal tube placement: a meta-analysis

OBJECTIVE

This meta-analysis aimed to summarize the evidence on the use of ultrasonography for confirming endotracheal tube placement in emergency departments.

MATERIALS AND METHODS

We conducted electronic searches on PubMed, Embase, Web of Science, and Cochrane databases. All databases were searched from their inception until February 2023. We selected studies published in English that used ultrasonography to confirm endotracheal tube placement. Case reports, case series, retrospective studies, cadaveric studies, pediatric studies, animal studies, and conference abstracts were excluded. Two reviewers independently extracted and verified data. Forest plots, hierarchical summary receiver operating characteristic (HSROC) curves, and bivariate random-effects models were used to summarize the test performance characteristics. The Stata statistical software package and Meta-DiSc version 1.4 software were used for statistical analysis.

RESULTS

A total of 1,772 intubations were analyzed. For the detection of endotracheal tube placement, the estimated pooled sensitivity and specificity were 0.98 (95% CI: 0.97-0.99) and 0.92 (95% CI 0.85-0.95), respectively. The pooled positive and negative likelihood ratios were 11.70 (95% CI: 6.49-21.07) and 0.02 (95% CI: 0.01-0.03), respectively. The diagnostic odds ratio of ultrasonography was 221.13, and the area under the HSROC curve revealed an appropriate accuracy of 0.99.

CONCLUSIONS

Current evidence supports the use of ultrasonography as a worthwhile alternative for endotracheal tube identification for intubations performed in emergency departments. This method can be used in conjunction with capnography as a preliminary test before final confirmation with capnography.

Omentin-1 ameliorates experimental inflammatory bowel disease via Nrf2 activation and redox regulation

AIMS

Omentin-1 production is decreased in patients with IBD. However, the specific role of Omentin-1 in IBD has not been fully elucidated. This study aimed to investigate the expression and role of Omentin-1 in IBD and the potential mechanisms.

MAIN METHODS

We collected human serum and colon biopsy samples at the Wuhan Union Hospital. Omentin-1 recombinant protein was injected intraperitoneally in a DSS-induced experimental IBD mouse model. Omentin-1 levels were measured in IBD patients, colitis mice, and LPS-induced HT-29 cells. Omentin-1 and/or a Nrf2 specific inhibitor (ML385) were administered to DSS mice and LPS-induced HT-29 cells. The effects of Omentin-1 on inflammation, intestinal barrier function, Nrf2 pathway, oxidative stress, and NF-κB signaling were detected in vivo and in vitro.

KEY FINDINGS

Serum Omentin-1 levels were significantly reduced in UC and CD patients compared with controls (173.7 (IQR, 120.1-221.2) ng/ml, 80.8 (43.8-151.8) ng/ml, and 270.7 (220.7-306.5) ng/ml, respectively). The levels of Omentin-1 were also significantly lower in colitis mice and LPS-induced HT-29 cells. Omentin-1 treatment effectively ameliorated inflammation and impaired intestinal barrier, decreased ROS and MDA levels, and increased GSH and SOD production in the DSS-induced colitis mice and LPS-induced HT-29 cells. Mechanically, Omentin-1 repaired the intestinal barrier by activating Nrf2, then improving oxidative stress and inhibiting NF-κB signaling. Furthermore, the interaction between Omentin-1 and Nrf2 was identified.

SIGNIFICANCE

Omentin-1 activates the Nrf2 pathway to regulate redox balance, ultimately protecting intestinal barrier function and reducing intestinal inflammation. In general, Omentin-1 can be used as a promising therapeutic target for IBD.

Different sedation profiles with ciprofol compared to propofol represented by objective sedation level assessments by BIS and its acute hemodynamic impact in 3 escalated doses of ciprofol and propofol in healthy subjects: a single-center, open-label, randomized, 2-stage, 2-way crossover trial

OBJECTIVE

To compare the sedation profiles and the pharmacokinetic, pharmacodynamic and safety characteristics of ciprofol and propofol at 3 escalated dose levels in healthy Chinese male subjects.

PATIENTS AND METHODS

Eighteen subjects were planned to be enrolled into 3 dose groups in turn: group 1 (ciprofol-0.4 mg/kg vs. propofol-2.0 mg/kg), group 2 (ciprofol-0.6 mg/kg vs. propofol-3.0 mg/kg) and group 3 (ciprofol-0.8 mg/kg vs. propofol-4.0 mg/kg). They were randomly assigned into a ciprofol or propofol group in a ratio of 1:1, with sequences of ciprofol-propofol or propofol-ciprofol, separated with a washout period of at least 48 h.

RESULTS

A total of 19 subjects were enrolled and 18 completed the trial. The median time to being fully alert after induction by ciprofol was longer than for propofol. The bispectral index (BIS) recovered significantly slower with ciprofol than with propofol 5 min and 10 min after reaching its lowest points. Systolic blood pressure (group 1: p=0.041; group 2: p=0.015; group 3: p=0.004) and mean arterial pressures (group 1: p=0.026; group 2: p=0.015; group 3: p=0.004) measured by the area under the curve below the baseline during the 2 min after induction were significantly less for ciprofol compared to propofol, but a significant change in diastolic blood pressure was only observed in group 3 (p=0.002). Eighteen (100.0%) subjects experienced 47 ciprofol-related treatment emergent adverse events (TEAEs) and 17 (94.4%) subjects had 54 propofol-related TEAEs, which were mainly hypotension, involuntary movements, respiratory depression, and pain at the injection site with severity of grade 1 or 2.

CONCLUSIONS

Ciprofol may be well tolerated at higher doses in the clinical practice and exhibited significantly different sedation profiles to propofol.

FACS-based genome-wide CRISPR screens define key regulators of DNA damage signaling pathways

DNA damage-activated signaling pathways are critical for coordinating multiple cellular processes, which must be tightly regulated to maintain genome stability. To provide a comprehensive and unbiased perspective of DNA damage response (DDR) signaling pathways, we performed 30 fluorescence-activated cell sorting (FACS)-based genome-wide CRISPR screens in human cell lines with antibodies recognizing distinct endogenous DNA damage signaling proteins to identify critical regulators involved in DDR. We discovered that proteasome-mediated processing is an early and prerequisite event for cells to trigger camptothecin- and etoposide-induced DDR signaling. Furthermore, we identified PRMT1 and PRMT5 as modulators that regulate ATM protein level. Moreover, we discovered that GNB1L is a key regulator of DDR signaling via its role as a co-chaperone specifically regulating PIKK proteins. Collectively, these screens offer a rich resource for further investigation of DDR, which may provide insight into strategies of targeting these DDR pathways to improve therapeutic outcomes.

The effect of recreational cannabis legalization and commercialization on substance use, mental health, and injury: a systematic review

OBJECTIVE

To determine the effect of recreational cannabis legalization (RCL) and/or recreational cannabis commercialization (RCC) on emergency department (ED) visits, hospitalizations, and deaths due to substance use, injury, and mental health among those aged 11 years and older.

METHODS

A systematic review of six electronic databases up to February 1, 2023. Original, peer-reviewed articles with interrupted time series or before and after designs were included. Four independent reviewers screened articles and assessed risk of bias. Outcomes with 'critical' risk of bias were excluded. Protocol registered on PROSPERO (# CRD42021265183).

RESULTS

After screening and risk of bias assessment, 29 studies were included which examined ED visits or hospitalizations for cannabis use or alcohol (N = 10), opioid mortality (N = 3), motor vehicle fatalities or injury (N = 11), and intentional injury/mental health (N = 5). Rates or number of cannabis-related hospitalizations increased after RCL in Canada and the USA. Immediate increases in rates of cannabis-related ED visits were found after both RCL and RCC in Canada. Rates of traffic fatalities increased after RCL and RCC in certain jurisdictions in the USA.

CONCLUSIONS

RCL was associated with increased rates of cannabis-related hospitalizations. RCL and/or RCC was associated with increased rates of cannabis-related ED visits, consistently shown across sex and age groups. The effect on fatal motor vehicle incidents was mixed, with observed increases found after RCL and/or RCC. The effect of RCL or RCC on opioids, alcohol, intentional injury, and mental health is not clear. These results inform population health initiatives and international jurisdictions considering RCL implementation.

Genome-Wide CRISPR Screens Reveal ZATT as a Synthetic Lethal Target of TOP2-Poison Etoposide That Can Act in a TDP2-Independent Pathway

Etoposide (ETO) is an anticancer drug that targets topoisomerase II (TOP2). It stabilizes a normally transient TOP2–DNA covalent complex (TOP2cc), thus leading to DNA double-strand breaks (DSBs). Tyrosyl-DNA phosphodiesterases two (TDP2) is directly involved in the repair of TOP2cc by removing phosphotyrosyl peptides from 5′-termini of DSBs. Recent studies suggest that additional factors are required for TOP2cc repair, which include the proteasome and the zinc finger protein associated with TDP2 and TOP2, named ZATT. ZATT may alter the conformation of TOP2cc in a way that renders the accessibility of TDP2 for TOP2cc removal. In this study, our genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) screens revealed that ZATT also has a TDP2-independent role in promoting cell survival following ETO treatment. ZATT KO cells showed relatively higher ETO sensitivity than TDP2-KO cells, and ZATT/TDP2 DKO cells displayed additive hypersensitivity to ETO treatment. The study using a series of deletion mutants of ZATT determined that the N-terminal 1–168 residues of ZATT are required for interaction with TOP2 and this interaction is critical to ETO sensitivity. Moreover, depletion of ZATT resulted in accelerated TOP2 degradation after ETO or cycloheximide (CHX) treatment, suggesting that ZATT may increase TOP2 stability and likely participate in TOP2 turnover. Taken together, this study suggests that ZATT is a critical determinant that dictates responses to ETO treatment and targeting. ZATT is a promising strategy to increase ETO efficacy for cancer therapy.

A sex- and site-specific relationship between body mass index and osteoarthritis: evidence from observational and genetic analyses

OBJECTIVE

We primarily aimed to investigate whether there are phenotypic and genetic links underlying body mass index (BMI) and overall osteoarthritis (OA). We then intended to explore whether the relationships differ across sexes and sites.

METHOD

We first evaluated the phenotypic association between BMI and overall OA using data from the UK Biobank. We then investigated the genetic relationship leveraging summary statistics of the hitherto largest genome-wide association studies performed for BMI and overall OA. Finally, we repeated all analyses in a sex- (female, male) and site- (knee, hip, spine) specific manner.

RESULTS

Observational analysis suggested an increased hazard of diagnosed OA per 5 kg/m² increment in BMI (hazard ratio = 1.38, 95% confidence interval (CI) = 1.37-1.39). A positive overall genetic correlation was observed for BMI and OA (r_g = 0.43, P = 4.72 × 10^-133), corroborated by 11 significant local signals. Cross-trait meta-analysis identified 34 pleiotropic loci shared between BMI and OA, of which seven were novel. Transcriptome-wide association study revealed 29 shared gene-tissue pairs, targeting nervous, digestive, and exo/endocrine systems. Mendelian randomization demonstrated a robust BMI-OA causal relationship (odds ratio = 1.47, 95% CI = 1.42-1.52). A similar pattern of effects was observed in sex- and site-specific analyses, with BMI affecting OA comparably in both sexes and most strongly in the knee.

CONCLUSION

Our work demonstrates an intrinsic relationship underlying BMI and overall OA, reflected by a pronounced phenotypic association, significant biological pleiotropy, and a putative causal link. Stratified analysis further reveals that the effects are distinct across sites and comparable across sexes.

Hypoxia-induced upregulation of matrix metalloproteinase 9 increases basement membrane degradation by downregulating collagen type IV alpha 1 chain

Hypoxia can cause basement membrane (BM) degradation in tissues. Matrix metalloproteinase 9 (MMP-9) is involved in various human cancers as well as BM degradation by downregulating type IV collagen (COL4). This study investigated the role of MMP-9 in hypoxia-mediated BM degradation in rat bone marrow based on its regulation of collagen type IV alpha 1 chain (COL4A1). Eighty male rats were randomly divided into four groups based on exposure to hypoxic conditions at a simulated altitude of 7,000 m, control (normoxia) and 3, 7, and 10 days of hypoxia exposure. BM degradation in bone marrow was determined by transmission electron microscopy. MMP-9 levels were assessed by western blot and real-time PCR, and COL4A1 levels were assessed by western blot and immunohistochemistry. Microvessels BMs in bone marrow exposed to acute hypoxia were observed by electron microscopy. MMP-9 expression increased, COL4A1 protein expression decreased, and BM degradation occurred in the 10-, 7-, and 3-day hypoxia groups compared with that in the control group (all P < 0.05). Hypoxia increased MMP-9 levels, which in turn downregulated COL4A1, thereby increasing BM degradation. MMP-9 upregulation significantly promoted BM degradation and COL4A1 downregulation. Our results suggest that MMP-9 is related to acute hypoxia-induced BM degradation in bone marrow by regulating COL4A1.

Comparative Sensitivity of Solid-Phase Versus PEG Enhancement Assays for Detection and Identification of Red Blood Cell Antibodies

Introduction/Objective

Identifying antibodies to red blood cell (RBC) antigens is one of transfusion medicine’s most critical and challenging issues. There are 354 RBC antigens recognized by the International Society of Blood Transfusion. Accurate identification of clinically significant alloantibodies is imperative for identifying and preventing hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. We compared the performance of the tube (polyethylene glycol–indirect antiglobulin test [PEG-IAT]) and solid-phase techniques for antibody identification.

Methods/Case Report

We performed a retrospective study on all antibody screens and identifications performed between 2007–2021 at Stanford Hospital. Over this period, 631,535 antibody screens were performed predominantly using an automated solid-phase technique. Subsequent antibody identification studies were performed using manual tube testing (PEG-IAT) and automated solid-phase techniques.

Results (if a Case Study enter NA)

Antibody screening resulted in 28,316 (4.5%) positive samples with at least one antibody. Antibody identification performed on both platforms identified 50 discordant [DMH1] samples. 8 anti-Jka, 2 anti-Jkb, 1 anti-S, and 1 anti-M were detected by automatic solid-phase technique but were not detected by PEG-IAT. 20 anti-E, 6 anti-K, 2 anti-Fya, 2 anti-c , 2 anti-C, 2 anti-Fyb, 1 anti-cE[DMH2] , 1 anti-e,1 anti-M, and 1 anti-S were detected by PEG-IAT but were negative by automated solid-phase technique. Anti-E had the least sensitivity (98.99%) in the automated solid-phase technique, while anti-Jkb had the least sensitivity (98.78%) in PEG-IAT.

Conclusion

This is the first robust 15-year study comparing methodologic sensitivity to detect clinically significant alloantibodies. The incidence of discordant results between the PEG-IAT and solid-phase technique was low. Among discordant samples, anti-Jka was commonly detected by solid-phase but not by PEG-IAT. In contrast, anti-E was commonly detected by PEG-IAT but not by the solid phase.

Racial Disparity in Antibody Against High Prevalence Antigen; Anti-U

Introduction/Objective

Anti-U is an IgG antibody directed against the U antigen, which usually forms after exposure to U antigen via blood transfusion and/or pregnancy. U antigen is located on glycophorin B (GYPB) as part of the MNS blood group system. Approximately 2% of the African American population lacks this antigen, making them prone to developing anti-U. Anti-U can cause hemolytic disease of fetus and newborn (HDFN) and hemolytic transfusion reactions (HTR).

Methods/Case Report

A 60-year-old African American male underwent aortic valve surgery. The patient was A Pos with a negative antibody screen. During surgery, the patient was transfused with 3 random units of packed red blood cells (PRBCs). The postoperative course was uncomplicated, and the patient was discharged home. 6 months later, the patient was admitted for another procedure and was expected to require blood products. Thus, a type and screen test was ordered, revealing pan reactivity on screening cells. This prompted further investigation. Antibody detection was performed with the solid-phase technique followed by the tube method with Polyethylene glycol (PEG) as an enhancement medium. PEG technique is the next choice of method if the solid phase requires extended antibody work up, which was the case in our patient. PEG tube method successfully identified Anti-U, and the patient's phenotype was confirmed to be U negative.

Results (if a Case Study enter NA)

N/A.

Conclusion

It is imperative to stress the importance of racial disparity while investigating antibodies against high prevalence. In our case, our suspicion was high for Anti-U, given that patient was of African American descent. Tube methods with PEG and Solid Phase techniques are usually used for antibody identification. It is recommended that patients with rare antibodies carry an Antibody ID card indicating the rare antibody they have to prevent further exposure.

Transtracheal ultrasound for confirmation of endotracheal tube placement in the intensive care unit: a systematic review and meta-analysis

OBJECTIVE

The major objective of this review was to compare the diagnostic accuracy of ultrasound in confirming tracheal intubation to the standard methods of confirmation in the intensive care unit (ICU).

MATERIALS AND METHODS

This systematic review and meta-analysis of observational studies was conducted from inception to July 2022. We included studies that compared the diagnostic accuracy of ultrasound-detected tracheal intubation to that of the gold standard diagnostic technique performed in adult patients who underwent tracheal intubation as part of any procedure. We searched the following electronic databases for published studies: PubMed, EMBASE, Cochrane Central, and Web of Science. Risk of bias was assessed using a standard procedure based on the Quality Assessment of Diagnostic Accuracy Studies-2 criteria. The results were analyzed using the RevMan or Meta-Disc software to determine the adequacy and conclusiveness of the available evidence.

RESULTS

Five studies that included 344 patients met the inclusion criteria. Pooled sensitivity was 0.96 (95% confidence interval (CI) (0.92-0.98) and 1.00 (95% CI: 0.97-1.00), respectively. Furthermore, the diagnostic odds ratio of ultrasonography was 311.25 (95% CI: 63.77-1,519.22), which was confirmed by a summary receiver operating characteristic curve with an area under the curve of 0.98.

CONCLUSIONS

Ultrasonography has high sensitivity and specificity, is a valuable adjunct for confirming tracheal intubation in the ICU and should be performed when capnography is unavailable or unreliable.

Long-term neurological intact survival and quality of life after refractory out-of-hospital cardiac arrest treated with rescue mechanical circulatory support

Background

Mechanical circulatory support (MCS) with either veno-arterial extracorporeal membrane oxygenation (V-A ECMO) or Impella has emerged as a rescue therapy for refractory out-of-hospital cardiac arrest (OHCA). However, only short-term outcome is specified and most studies do not report follow-up beyond six months. Long-term survival and quality of life in this high-risk population remains unknown.

Purpose

To determine long-term neurological intact survival and quality of life in patients with refractory OHCA treated with MCS.

Methods

This was an observational, single-centre study of OHCA-patients from January 2015 to December 2019. Patients treated with MCS for OHCA were compared with patients receiving conventional cardiopulmonary resuscitation (CPR). A follow-up of long-term survivors in the MCS group was conducted (&gt;1 year after arrest). This included health related quality of life questionaries (Short Form-36 [SF-36]) and assessment of neurological function with Cerebral Performance Category (CPC). Good neurological outcome was defined as CPC 1 and CPC 2.

Results

A total of 1015 with OHCA were included; 101 received MCS for refractory cardiac arrest. Among these V-A ECMO was deployed in 97 patients and Impella in 4 patients. The MCS group had significantly longer low-flow times compared to the conventional group (105 [IQR, 94–123] minutes versus 18 [IQR 10–39] minutes) and were more metabolically deranged upon arrival at hospital (Table 1). In patients receiving MCS, the hospital discharge rate was 27% and good neurological outcome was seen in 93% among patients discharged. At follow-up, 15 out of 21 long-term survivors participated. Median follow-up time was 4.8±1.6 (range 2.8–6.1 years). Mean age at follow-up was 61±7.3 years, 11 (73%) were men. Neurological outcome with CPC 1 was found in 12 patients (80%), with CPC 2 in 2 patients (13%), and with CPC 3 in 1 patient (7%). Two had improved neurological status from CPC 2 to CPC 1 since discharge. Mean scores of the SF-36 revealed an overall high level of psychical and mental health in long-term survivors (Figure 1).

Conclusion

Long-term survival with good neurological outcome was high in patients with refractory OHCA treated with MCS despite prolonged resuscitation and severe metabolic derangement. These patients may expect a reasonable quality of life after discharge.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Department of Cardiology, Aarhus University HospitalSnedkermester Sophus Jacobsen og hustru Astrid Jacobsens Fond

The diagnostic values of lung ultrasound for ARDS

OBJECTIVE

Acute respiratory distress syndrome (ARDS) is a critical disease commonly found in many clinical cases, with a mortality rate of approximately 50%. Early diagnosis and intervention are important for improving ARDS prognosis. In this study, the applications of lung ultrasound in ARDS diagnosis and assessment are reviewed to clarify its key clinical values and application prospects.

MATERIALS AND METHODS

According to the standard diagnosis of ARDS based on the Berlin definition, CXR or CT examination should be conducted. However, both the blurred images of the former, as well as the inconvenience and high risks of the latter, impose restrictions on their application in critically ill patients.

RESULTS

Lung ultrasound was shown to improve safety, effectiveness, lacked radiation, can be performed bedside, and offers dynamic functionality.

CONCLUSIONS

It may be a suitable approach to replace or complement traditional imaging examinations with lung ultrasound.

Diagnostic accuracy of ultrasonography for detecting gastric tube placement: an updated meta-analysis

OBJECTIVE

This study aimed at reviewing the diagnostic accuracy of ultrasonography for detecting correct nasogastric tube placement compared with X-ray imaging as the reference standard.

MATERIALS AND METHODS

This was a systematic review and meta-analysis of observational studies published between 1961 and 2022. We included studies that compared the diagnostic accuracy of ultrasound detection for nasogastric tube placement with that of X-ray imaging in adult patients who were undergoing nasogastric tube placement for any reason. We searched for published studies in the following electronic databases: Cochrane Library, PubMed, EMBASE, and Web of Science. The risk of bias was assessed using a standard procedure according to the Quality Assessment of Diagnostic Accuracy Studies-2 criteria. The results were analyzed using RevMan or Meta-Disc software to determine the adequacy and conclusiveness of the available evidence.

RESULTS

Fourteen studies met our inclusion criteria. Overall, 1,812 patients were included in these studies. The results included a pooled sensitivity of 0.96 (95% confidence interval [CI] 0.94-0.97), specificity of 0.91 (95% CI 0.85-0.96), positive likelihood ratio of 5.08 (95% CI 1.49-17.39), and negative likelihood ratio of 0.08 (95% CI 0.06-0.10). This was confirmed through a summary receiver operating characteristic curve, which showed that the area under the curve was 0.96.

CONCLUSIONS

We found evidence about validity of ultrasound as an efficient method for verifying nasogastric tube placement, although there is insufficient evidence to suggest that it can be used as a diagnostic tool for incorrect gastric tube placement.

High-Resolution MRI for Evaluation of the Possibility of Successful Recanalization in Symptomatic Chronic ICA Occlusion: A Retrospective Study

BACKGROUND AND PURPOSE

Accurate radiologic evaluation of the possibility of successful recanalization in symptomatic chronic ICA occlusion remains challenging. This study aimed to investigate the high-resolution MR imaging characteristics of symptomatic chronic ICA occlusion and their association with successful recanalization.

MATERIALS AND METHODS

Consecutive patients with symptomatic chronic ICA occlusion who underwent balloon dilation plus stent implantation were identified retrospectively and divided into 2 groups: a successful recanalization group and an unsuccessful recanalization group. Clinical and high-resolution MR imaging characteristics were compared between the groups. Univariate and multivariate analyses were used to identify the characteristics associated with successful recanalization.

RESULTS

A total of 114 patients were included in the study. High-resolution MR imaging characteristics independently associated with unsuccessful recanalization were longer lesion length (OR, 0.41; 95% CI, 0.36-0.55; P = .009) and larger calcification volume (OR, 0.56; 95% CI, 0.37-0.68; P = .002) for proximal occlusion and reversed distal ICA flow at the level of ophthalmic segment or above (OR, 0.14; 95% CI, 0.08-0.48; P = .001). Reversed distal ICA flow at the level of the petrous segment or below (OR, 4.07; 95% CI, 1.65-8.38; P = .001) and lumen area (OR, 1.13; 95% CI, 1.04-1.61; P = .002) for distal occlusion were risk factors of successful recanalization.

CONCLUSIONS

In symptomatic chronic ICA occlusion, lesion length and calcification volume (for proximal occlusion), the level of reversed distal ICA flow, and the lumen area (for distal occlusion) appear to be predictors of successful recanalization. High-resolution MR imaging can evaluate chronic ICA occlusion and help in clinical decision-making.

Integrated screens uncover a cell surface tumor suppressor gene KIRREL involved in Hippo pathway

Cell surface proteins play essential roles in various biological processes and are highly related to cancer development. They also serve as important markers for cell identity and targets for pharmacological intervention. Despite their great potentials in biomedical research, comprehensive functional analysis of cell surface proteins remains scarce. Here, with a de novo designed library targeting cell surface proteins, we performed in vivo CRISPR screens to evaluate the effects of cell surface proteins on tumor survival and proliferation. We found that Kirrel1 loss markedly promoted tumor growth in vivo. Moreover, KIRREL was significantly enriched in a separate CRISPR screen based on a specific Hippo pathway reporter. Further studies revealed that KIRREL binds directly to SAV1 to activate the Hippo tumor suppressor pathway. Together, our integrated screens reveal a cell surface tumor suppressor involved in the Hippo pathway and highlight the potential of these approaches in biomedical research.

Fourfold Anisotropic Magnetoresistance of L1_{0} FePt Due to Relaxation Time Anisotropy

Experimental measurements show that the angular dependence of the anisotropic magnetoresistance (AMR) in L1_{0} ordered FePt epitaxial films on the current orientation and magnetization direction is a superposition of the corresponding dependences of twofold and fourfold symmetries. The twofold AMR exhibits a strong dependence on the current orientation, whereas the fourfold term only depends on the magnetization direction in the crystal and is independent of the current orientation. First-principles calculations reveal that the fourfold AMR arises from the relaxation time anisotropy due to the variation of the density of states near the Fermi energy under rotation of the magnetization. This relaxation time anisotropy is a universal property in ferromagnetic metals and determines other anisotropic physical properties that are observable in experiment.

Genome-wide CRISPR screens using isogenic cells reveal vulnerabilities conferred by loss of tumor suppressors

Exploiting cancer vulnerabilities is critical for the discovery of anticancer drugs. However, tumor suppressors cannot be directly targeted because of their loss of function. To uncover specific vulnerabilities for cells with deficiency in any given tumor suppressor(s), we performed genome-scale CRISPR loss-of-function screens using a panel of isogenic knockout cells we generated for 12 common tumor suppressors. Here, we provide a comprehensive and comparative dataset for genetic interactions between the whole-genome protein-coding genes and a panel of tumor suppressor genes, which allows us to uncover known and new high-confidence synthetic lethal interactions. Mining this dataset, we uncover essential paralog gene pairs, which could be a common mechanism for interpreting synthetic lethality. Moreover, we propose that some tumor suppressors could be targeted to suppress proliferation of cells with deficiency in other tumor suppressors. This dataset provides valuable information that can be further exploited for targeted cancer therapy.

715 REDUCING OVERTREATMENT OF TYPE 2 DIABETES IN OLDER PEOPLE LIVING IN CARE HOMES

Introduction

Older people in care homes living with frailty are less likely to benefit from tight glycaemic control in the management of type 2 diabetes with increased risk of adverse effects for example hypoglycaemia, falls and hospital admission. We wished to ascertain the scale of the problem and reduce overtreatment. We defined overtreatment based on American Diabetes Association guidelines as being on an agent that can cause hypoglycaemia and having an HBA1C of ≤53 mmol/mol or, an HbA1c 53–64 mmol/mol with either three or more co-morbidities.

Methods

In 2016, we audited the management of type 2 diabetes in older people discharged from LTHT to care homes. We discussed our concerns with diabetes and geriatric medicine colleagues across medical, nursing and pharmacy disciplines. We engaged the support of the citywide diabetes network which comprises secondary care colleagues, general practitioners and pharmacists. We presented the findings of our initial audit to colleagues within primary and secondary care through departmental meetings and citywide network meetings. We wrote a new guideline, specifically for frail older people that was disseminated citywide through these networks. We re-audited in 2020.

Results

In total, 113 cases were reviewed in 2016 and 105 cases in 2020. In 2020, only 6% (6 patients) were overtreated compared to 38% (43 patients) in 2016.

Conclusions

There has been a marked reduction in overtreatment which should result in less adverse events. We believe the reasons for success lie in wide engagement of relevant stakeholder groups around an issue that is important, large in scale and meaningful to both patient and clinician. There are potential cost savings from reducing medications and reducing harm.

Gompertz model in COVID-19 spreading simulation

The paper reports on application of the Gompertz model to describe the growth dynamics of COVID-19 cases during the first wave of the pandemic in different countries. Modeling has been performed for 23 countries: Australia, Austria, Belgium, Brazil, Great Britain, Germany, Denmark, Ireland, Spain, Italy, Canada, China, the Netherlands, Norway, Serbia, Turkey, France, Czech Republic, Switzerland, South Korea, USA, Mexico, and Japan. The model parameters are determined by regression analysis based on official World Health Organization data available for these countries. The comparison of the predictions given by the Gompertz model and the simple logistic model (i.e., Verhulst model) is performed allowing to conclude on the higher accuracy of the Gompertz model.

Low-density-lipoprotein-receptor-related protein 1 mediates Notch pathway activation

The Notch signaling pathway controls cell growth, differentiation, and fate decisions, and its dysregulation has been linked to various human genetic disorders and cancers. To comprehensively understand the global organization of the Notch pathway and identify potential drug targets for Notch-related diseases, we established a protein interaction landscape for the human Notch pathway. By combining and analyzing genetic and phenotypic data with bioinformatics analysis, we greatly expanded this pathway and identified many key regulators, including low-density-lipoprotein-receptor-related protein 1 (LRP1). We demonstrated that LRP1 mediates the ubiquitination chain linkage switching of Delta ligands, which further affects ligand recycling, membrane localization, and stability. LRP1 inhibition led to Notch signaling inhibition and decreased tumorigenesis in leukemia models. Our study provides a glimpse into the Notch pathway interaction network and uncovers LRP1 as one critical regulator of the Notch pathway, as well as a possible therapeutic target for Notch-related cancers.

Anatomical dilation for the coronary sinus ostium in patients with pulmonary arterial hypertension and its impact to trigger the atrioventricular reentrant tachycardia: a case control study

Background

The incidence of atrioventricular reentrant tachycardia (AVNRT) in pulmonary arterial hypertension (PAH) patients is higher than the general population [1–3]. AVNRT had been reported with larger coronary sinus (CS) ostium in general population, while the mechanism and correlation between AVNRT and the CS ostium in PAH patients are poorly understood.

Purpose

We aim to investigate the impact of the CS ostium on AVNRT and find out its risk factors in PAH patients.

Methods

Of 102 pulmonary arterial hypertension (PAH) patients with catheter ablation of SVT, 10 patients confirmed AVNRT who underwent computed tomographic angiography (CTA) were enrolled as study group. The control group (PAH patients without SVT, n=20) were matched in a ratio of 2:1 based on gender and BMI. We measured maxium diameter of CS ostium in axial and LAO plane by CTA. All baseline characteristics and imaging materials were collected.

Results

PAH patients with AVNRT were older (45.9±14.8 vs. 32.1±7.6 years, P=0.025) and more likely to have larger CS ostium in LAO plane (18.6±3.3 vs. 14.8±4.0 mm, P=0.011) than those without AVNRT. The maximal diameter of CS ostium in LAO plane was an independent predictor for AVNRT in PAH patients (Odds ratio, 1.389; 95% confidence interval, 1.003–1.923; P=0.048). The cut-off value of CS ostium in LAO plane was 14.1mm (Area under curve = 0.79, P=0.012), and the sensitivity and specificity were 90% and 55%, respectively.

Conclusions

The larger CS ostium in LAO plane correlated with the higher prevalence of AVNRT in PAH patients with age. Patients with CS ostium larger than 14.1mm in LAO plane are more likely to develop AVNRT.

Funding Acknowledgement

Type of funding sources: None. Measurements and diagnosis value

Acute arterial events across all vascular territories in the FOURIER trial

Background

In the FOURIER (Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Patients With Elevated Risk) trial, adding the PCSK9 inhibitor evolocumab to statin therapy reduced low-density lipoprotein cholesterol (LDL-C) and cardiovascular risk. Although atherosclerotic coronary, cerebrovascular, and peripheral vascular events share a related pathobiology, the effect of aggressive LDL-C lowering with PCSK9 inhibition on the risk of acute arterial events across all three vascular beds is not well-described.

Purpose

To assess the efficacy of evolocumab on acute arterial events in all vascular territories including coronary, cerebral, and peripheral vascular beds.

Methods

In the FOURIER trial, patients (n=27,564) with stable atherosclerotic cardiovascular disease and LDL-C ≥70 mg/dL on a statin were randomly assigned to evolocumab versus placebo and followed for a median of 2.2 years (1.8–2.5). Acute arterial events were defined as a composite of coronary (coronary heart disease [CHD] death, myocardial infarction [MI], or urgent coronary revascularization), cerebrovascular (ischemic stroke, transient ischemic attack [TIA], or urgent cerebral revascularization), or peripheral vascular (acute limb ischemia, major amputation, or urgent peripheral revascularization) events. Cox proportional-hazard models were used to assess the efficacy of evolocumab on these outcomes. Landmark and total event analyses were also done.

Results

Of the 2,210 first acute arterial events occurring during follow-up, 74% were coronary, 22% were cerebrovascular, and 4% were peripheral vascular. Evolocumab reduced the risk of a first acute arterial event by 19% (HR 0.81, 95% CI 0.74–0.88; P&lt;0.001), with significant individual reductions in acute coronary (HR 0.83; 95% CI 0.75–0.91; P&lt;0.001), acute cerebrovascular (HR 0.77; 95% CI 0.65–0.92; P=0.004), and acute peripheral vascular (HR 0.58; 95% CI 0.38–0.88; P=0.01) events (Figure, top). The magnitude of the risk reduction with evolocumab tended to increase over time, with a 16% reduction (HR 0.84; 95% CI 0.75–0.96) in the first year followed by a 24% reduction (HR 0.76; 95% CI 0.67–0.85) thereafter (Figure, bottom). There were 3,780 total acute arterial events (first plus recurrent), with a 22% reduction with evolocumab (incidence rate ratio [RR] 0.78; 95% CI 0.70–0.87). Evolocumab prevented 496 total acute arterial events as compared to 222 first events.

Conclusions

The addition of the PCSK9 inhibitor evolocumab to statin therapy reduced the risk of acute arterial events across all vascular territories with a robust effect over time. These findings indicate a pan-vascular impact of aggressive lipid-lowering therapy on these acute and clinically meaningful events.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): The FOURIER trial was supported by Amgen.

Mechanical circulatory support for refractory out-of-hospital cardiac arrest: a nationwide multicentre study

Background

Extracorporeal cardiopulmonary resuscitation (ECPR) has shown potential as a salvage therapy for patients with refractory out-of-hospital cardiac arrest (OHCA). Despite growing interest in and a growing body of literature on ECPR for refractory OHCA, robust evidence on patient eligibility is still lacking.

Purpose

To describe the survival, neurological outcome, and adherence to the national consensus with respect to use of ECPR for OHCA, and to identify factors associated with outcome.

Methods

Retrospective, observational cohort study of patients who underwent ECPR for OHCA at four cardiac arrest centres. Binary logistic regression and Kaplan-Meier survival curves were performed to assess association with 30-day mortality.

Results

A total of 259 patients receiving ECPR for OHCA between July 2011 and December 2020 were included in the study. Thirty-day survival was 26% and a good neurological outcome Cerebral Performance Category (CPC) 1–2 was observed in 94% of patients at discharge. Strict adherence to the national consensus showed a 30-day survival rate of 30%. Adding one or more of the following criteria to the national consensus: signs of life during cardiopulmonary resuscitation (CPR), pre-hospital low-flow &lt;100 minutes, pH &gt;6.8 and lactate &lt;15 mmol/L increased the survival rate to 48%, but would exclude 58% of the survivors from the current cohort. Logistic regression identified initial presenting rhythm with asystole (RR 1.36, 95% CI 1.18–1.57), pulseless electrical activity (PEA) (RR 1.20, 95% CI 1.03–1.41), initial pH &lt;6.8 (RR 1.28, 95% CI 1.12–1.46) and lactate levels &gt;15 mmol/L (RR 1.16, 95% CI 1.16–1.53) as factors associated with increased risk of 30-day mortality. Patients presenting signs of life during CPR had threefold higher survival rate than patients without signs of life (45% versus 13%, p&lt;0.001)

Conclusion

A high survival rate with a good neurological outcome was observed in this population of patients treated with ECPR for OHCA. Signs of life during CPR may aid the decision-making in the selection of appropriate candidates. Stringent patient selection for ECPR may produce higher survival rates but potentially withholds life-saving treatment in a significant proportion of survivors, why optimization of the selection criteria is still necessary.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): This work was supported by the Danish Heart Foundation [20-R142-A9498-22178]; and Health Research Foundation of Central Denmark Region [R64-A3178-B1349] Survival and adherence to consensusSigns of life during CPR

Characteristics and long-term ablation outcomes of supraventricular arrhythmias in hypertrophic cardiomyopathy: a 10-year, single-center experience

Background

A variety of supraventricular arrhythmias (SVAs) may occur in patients with hypertrophic cardiomyopathy (HCM). The characteristics and long-term ablation outcomes of different types of SVAs in HCM have not been comprehensively investigated.

Methods

We retrospectively enrolled 101 consecutive symptomatic HCM patients with suspected arrhythmia from May 2010 to October 2020. The clinical features and ablation outcomes of patients with SVAs were further analyzed.

Results

Seventy-eight patients had SVAs, consisting of 50 (64.1%) atrial fibrillation (AF), 16 (20.5%) atrial flutter (AFL), 15 (19.2%) atrioventricular reentrant tachycardia (AVRT), 11 (14.1%) atrial arrhythmia (AT), and 3 (3.8%) atrioventricular nodal reentrant tachycardia (AVNRT). Thirty-four patients underwent catheter ablation including 14 for AF, 9 for AVRT, 6 for AFL, 3 for AVNRT, 1 for both AF and AFL, and 1 for both AF and AVRT. They were followed up for a median (interquartile range) of 58.5 (82.9) months. There were no recurrences for patients with non-AF SVAs. For patients with AF, the 1- and 7-year AF-free survival were 87.5% and 49.5%, respectively. A ROC analysis revealed that a greater left ventricular end-diastolic dimension (LVEDD) was associated with higher recurrence of AF with an optimum cutoff value of 47mm (c-statistic = 0.91, p=0.011, sensitivity = 1.00, specificity = 0.82). In Kaplan-Meier analysis, patients with LVEDD ≥47mm had worse AF-free survival (log-rank p=0.014).

Conclusions

AF is the most common SVA in HCM, with AFL, AVRT, AT, and AVNRT ranking the second to the last according to the prevalence. The long-term catheter ablation outcome for non-AF SVAs in HCM is satisfying. A greater LVEDD predicts AF recurrence after catheter ablation in patients with HCM.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): National Natural Science Foundation of China Figure 1Figure 2

Idiopathic ventricular arrhythmias ablating from different subregions in the aortic sinus cusps: anatomic distribution, electrocardiography, and electrophysiology characteristics

Background

Previous studies had described the electrocardiographic or electrophysiological characteristics of ventricular arrhythmias (VAs) from 3 aortic sinus cusps (ASC) as a whole, while little is known about the differences among VAs ablated in different subregions of the ASC.

Objective

To investigate the distribution, specific precordial electrocardiographic sign, and bipolar electrogram characteristics of VAs ablated in different subregions of the ASC.

Methods

We divided the right coronary cusp (RCC) and the left coronary cusp (LCC) into 6 subregions and studied 51 idiopathic VAs ablated successfully in the ASC.

Results

Fifty-one VAs inhomogeneous distributed in the 6 subregions, which rarely located in the lateral RCC (L-RCC; 2%). The fractionated potential was dominant (39/51, 76%) in the three kinds of target electrograms. From the L-RCC to the lateral LCC (L-LCC), the percentage of fractionated potential gradually decreased from 100% to 59%. A precordial rebound notch in V3–4 or V4–5 had a sensitivity of 90.9%, a specificity of 85.0%, and a negative predictive value (NPV) of 97.1% to predict VAs ablating from the anterior RCC (A-RCC). A precordial rebound notch in V2–3 had a sensitivity of 50.0%, a specificity of 94.9%, and a NPV of 86.0% to predict VAs ablating from the L-LCC.

Conclusion

The targets of the ASC-VAs mainly distributed in the anterior ASC and the L-LCC. Fractionated potential is common among target bipolar electrograms especially in the anterolateral RCC. Precordial electrocardiographic rebound notch has a high predictive accuracy for identifying different subregions of the ASC-VAs.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Genome-wide CRISPR screens reveal cyclin C as synthetic survival target of BRCA2

Poly (ADP-ribose) polymerase inhibitor (PARPi)-based therapies initially reduce tumor burden but eventually lead to acquired resistance in cancer patients with BRCA1 or BRCA2 mutation. To understand the potential PARPi resistance mechanisms, we performed whole-genome CRISPR screens to discover genetic alterations that change the gene essentiality in cells with inducible depletion of BRCA2. We identified that several RNA Polymerase II transcription Mediator complex components, especially Cyclin C (CCNC) as synthetic survival targets upon BRCA2 loss. Total mRNA sequencing demonstrated that loss of CCNC could activate the transforming growth factor (TGF)-beta signaling pathway and extracellular matrix (ECM)-receptor interaction pathway, however the inhibition of these pathways could not reverse cell survival in BRCA2 depleted CCNC-knockout cells, indicating that the activation of these pathways is not required for the resistance. Moreover, we showed that the improved survival is not due to restoration of homologous recombination repair although decreased DNA damage signaling was observed. Interestingly, loss of CCNC could restore replication fork stability in BRCA2 deficient cells, which may contribute to PARPi resistance. Taken together, our data reveal CCNC as a critical genetic determinant upon BRCA2 loss of function, which may help the development of novel therapeutic strategies that overcome PARPi resistance.

Genetic vulnerabilities upon inhibition of DNA damage response

Because of essential roles of DNA damage response (DDR) in the maintenance of genomic integrity, cellular homeostasis, and tumor suppression, targeting DDR has become a promising therapeutic strategy for cancer treatment. However, the benefits of cancer therapy targeting DDR are limited mainly due to the lack of predictive biomarkers. To address this challenge, we performed CRISPR screens to search for genetic vulnerabilities that affect cells’ response to DDR inhibition. By undertaking CRISPR screens with inhibitors targeting key DDR mediators, i.e. ATR, ATM, DNAPK and CHK1, we obtained a global and unbiased view of genetic interactions with DDR inhibition. Specifically, we identified YWHAE loss as a key determinant of sensitivity to CHK1 inhibition. We showed that KLHL15 loss protects cells from DNA damage induced by ATM inhibition. Moreover, we validated that APEX1 loss sensitizes cells to DNAPK inhibition. Additionally, we compared the synergistic effects of combining different DDR inhibitors and found that an ATM inhibitor plus a PARP inhibitor induced dramatic levels of cell death, probably through promoting apoptosis. Our results enhance the understanding of DDR pathways and will facilitate the use of DDR-targeting agents in cancer therapy.

Interactomes of SARS-CoV-2 and human coronaviruses reveal host factors potentially affecting pathogenesis

Host-virus protein-protein interactions play key roles in the life cycle of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We conducted a comprehensive interactome study between the virus and host cells using tandem affinity purification and proximity-labeling strategies and identified 437 human proteins as the high-confidence interacting proteins. Further characterization of these interactions and comparison to other large-scale study of cellular responses to SARS-CoV-2 infection elucidated how distinct SARS-CoV-2 viral proteins participate in its life cycle. With these data mining, we discovered potential drug targets for the treatment of COVID-19. The interactomes of two key SARS-CoV-2-encoded viral proteins, NSP1 and N, were compared with the interactomes of their counterparts in other human coronaviruses. These comparisons not only revealed common host pathways these viruses manipulate for their survival, but also showed divergent protein-protein interactions that may explain differences in disease pathology. This comprehensive interactome of SARS-CoV-2 provides valuable resources for the understanding and treating of this disease.

[Role of long noncoding RNA SNHG3 in regulating proliferation, migration and invasion of cervical cancer SiHa cells]

OBJECTIVE

To investigate the regulatory role of the long non-coding RNA (lncRNA) small nucleolar host gene 3 (SNHG3) in proliferation, migration and invasion of human cervical cancer cell line SiHa.

OBJECTIVE

Array data were retrieved from GEO database to analyze the expression levels of SNHG3 in cervical cancer and adjacent normal tissues. SiHa cells were transfected with a small interfering RNA (siRNA) targeting SNHG3, and the changes in the transcriptional levels of lncRNA SNHG3 and the epithelial-mesenchymal transition (EMT) markers N-cadherin, Snail, vimentin and E-cadherin were detected using real-time quantitative PCR; the protein expressions of N-cadherin, Snail, vimentin and E-cadherin were determined using Western blotting. Cell counting kit-8 (CCK8) assay was utilized to assess the proliferation capacity of the transfected cells. Wound healing assay and Transwell assay were performed to evaluate the transversal and longitudinal migration and invasion abilities of the cells.

OBJECTIVE

SNHG3 was over-expressed in cervical cancer tissues and SiHa cells. In SiHa cells, knocking down SNHG3 significantly inhibited the proliferation (P < 0.001), migration (P < 0.01) and invasion abilities (P < 0.001) of the cells, down-regulated the expression levels of N-cadherin, Snail and vimentin (P < 0.001) and up-regulated the expression of E-cadherin (P < 0.001).

OBJECTIVE

SNHG3 may promote the proliferation, migration and invasion of SiHa cells by activating the EMT signaling pathway.

Application of remote online learning in oral histopathology teaching in China

Background

The aim of this study was to investigate the application of remote learning and virtual microscopy in oral histopathology teaching, a unique experience in China. The oral histopathology teaching in Nanjing Medical University has been extraordinary.

Material and Methods

98 third-year dental students of Grade 2016 took oral histopathology theoretical course face-to-face in 2019 (Traditional group). The 94 participants of Grade 2017 took online oral histopathology course using digital methods(E-Learning platform and Virtual Simulation Experiment Teaching Center for Dentistry) in 2020. During the practical laboratory sessions, the students in both Traditional group and Online group observed the same glass slides for morphological learning. A questionnaire survey explored students' attitudes towards the remote online learning. Results: The mean Theory test scores of the Online group (80.93±12.15) were significantly higher than those of the Traditional group (73.65±8.46) (P < 0.01). The mean total scores of the Online group (82.94±10.76) were significantly higher than those of the Traditional group (77.25±7.55) (P < 0.01). The percentage of high total test score (test score > 85) of the Online group (54%) was also significantly higher than that of the Traditional group (15%) (P< 0.01). Furthermore, both remote learning and virtual microscopy courses were well accepted by students according to the questionnaire.

Conclusions

This study found that remote learning and virtual technology have a positive impact on oral histopathology. The findings reveal that the application of remote online learning has enhanced oral histopathology teaching in China.

Key words:Oral histopathology, dental undergraduate students, virtual microscopy, remote online learning, questionnaire.

DNA polymerase β may be involved in protecting human bronchial epithelial cells from the toxic effects induced by methyl tert-butyl ether exposure

Methyl tert-butyl ether (MTBE), a widely used gasoline additive and a ubiquitous environmental pollutant in many countries and regions, can cause various kinds of toxic effects on human health. However, the molecular mechanism underlying its toxic effects remains elusive. The present study aimed to explore the cytotoxicity, DNA damage and oxidative damage effects of MTBE on human bronchial epithelial cells (16HBE) and the possible role of DNA polymerase β (pol-β) in this process. RNA interference (RNAi) was used to obtain pol-β gene knocked-down cells (pol-β^-). CCK-8 assay was adopted to analyze the cell viability. Alkaline single-cell gel electrophoresis (SCGE) was performed to detect the DNA damage effects of MTBE. The enzyme activity of GSH-Px, SOD, CAT and the level of MDA were assessed. The data indicated that when treated with MTBE at the concentration exceeding 50 μmol/L and for the time exceeding 24 h, the pol-β^- exhibited significantly decreased cell viability and increased DNA damage effects, as compared to the control (P < 0.05). Furthermore, there was significant difference in the levels of GSH-pX, SOD, CAT and MDA between the pol-β^- and the control (P < 0.05). Our investigation suggests that MTBE can cause obvious cytotoxicity, DNA damage and oxidative damage effects on 16HBE cells. DNA polymerase β may be involved in protecting 16HBE cells from the toxic effects induced by MTBE exposure. These findings provide a novel insight into the molecular mechanism underlying the toxic effects of MTBE on human cells.

Comparative analysis of mouse and human preimplantation development following POU5F1 CRISPR/Cas9 targeting reveals interspecies differences

STUDY QUESTION

What is the role of POU class 5 homeobox 1 (POU5F1) in human preimplantation development and how does it compare with the mouse model?

SUMMARY ANSWER

POU5F1 is required for successful development of mouse and human embryos to the blastocyst stage as knockout embryos exhibited a significantly lower blastocyst formation rate, accompanied by lack of inner cell mass (ICM) formation.

WHAT IS KNOWN ALREADY

Clustered regularly interspaced short palindromic repeats-CRISPR associated genes (CRISPR-Cas9) has previously been used to examine the role of POU5F1 during human preimplantation development. The reported POU5F1-targeted blastocysts always retained POU5F1 expression in at least one cell, because of incomplete CRISPR-Cas9 editing. The question remains of whether the inability to obtain fully edited POU5F1-targeted blastocysts in human results from incomplete editing or the actual inability of these embryos to reach the blastocyst stage.

STUDY DESIGN, SIZE, DURATION

The efficiency of CRISPR-Cas9 to induce targeted gene mutations was first optimized in the mouse model. Two CRISPR-Cas9 delivery methods were compared in the B6D2F1 strain: S-phase injection (zygote stage) (n = 135) versus metaphase II-phase (M-phase) injection (oocyte stage) (n = 23). Four control groups were included: non-injected media-control zygotes (n = 43)/oocytes (n = 48); sham-injected zygotes (n = 45)/oocytes (n = 47); Cas9-protein injected zygotes (n = 23); and Cas9 protein and scrambled guide RNA (gRNA)-injected zygotes (n = 27). Immunofluorescence analysis was performed in Pou5f1-targeted zygotes (n = 37), media control zygotes (n = 19), and sham-injected zygotes (n = 15). To assess the capacity of Pou5f1-null embryos to develop further in vitro, additional groups of Pou5f1-targeted zygotes (n = 29) and media control zygotes (n = 30) were cultured to postimplantation stages (8.5 dpf). Aiming to identify differences in developmental capacity of Pou5f1-null embryos attributed to strain variation, zygotes from a second mouse strain-B6CBA (n = 52) were targeted. Overall, the optimized methodology was applied in human oocytes following IVM (metaphase II stage) (n = 101). The control group consisted of intracytoplasmically sperm injected (ICSI) IVM oocytes (n = 33). Immunofluorescence analysis was performed in human CRISPR-injected (n = 10) and media control (n = 9) human embryos.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A gRNA-Cas9 protein mixture targeting exon 2 of Pou5f1/POU5F1 was microinjected in mouse oocytes/zygotes or human IVM oocytes. Reconstructed embryos were cultured for 4 days (mouse) or 6.5 days (human) in sequential culture media. An additional group of mouse-targeted zygotes was cultured to postimplantation stages. Embryonic development was assessed daily, with detailed scoring at late blastocyst stage. Genomic editing was assessed by immunofluorescence analysis and next-generation sequencing.

MAIN RESULTS AND THE ROLE OF CHANCE

Genomic analysis in mouse revealed very high editing efficiencies with 95% of the S-Phase and 100% of the M-Phase embryos containing genetic modifications, of which 89.47% in the S-Phase and 84.21% in the M-Phase group were fully edited. The developmental capacity was significantly compromised as only 46.88% embryos in the S-Phase and 19.05% in the M-Phase group reached the blastocyst stage, compared to 86.36% in control M-Phase and 90.24% in control S-Phase groups, respectively. Immunofluorescence analysis confirmed the loss of Pou5f1 expression and downregulation of the primitive marker SRY-Box transcription factor (Sox17). Our experiments confirmed the requirement of Pou5f1 expression for blastocyst development in the second B6CBA strain. Altogether, our data obtained in mouse reveal that Pou5f1 expression is essential for development to the blastocyst stage. M-Phase injection in human IVM oocytes (n = 101) similarly resulted in 88.37% of the POU5F1-targeted embryos being successfully edited. The developmental capacity of generated embryos was compromised from the eight-cell stage onwards. Only 4.55% of the microinjected embryos reached the late blastocyst stage and the embryos exhibited complete absence of ICM and an irregular trophectoderm cell layer. Loss of POU5F1 expression resulted in absence of SOX17 expression, as in mouse. Interestingly, genetic mosaicism was eliminated in a subset of targeted human embryos (9 out of 38), three of which developed into blastocysts.

LIMITATIONS, REASONS FOR CAUTION

One of the major hurdles of CRISPR-Cas9 germline genome editing is the occurrence of mosaicism, which may complicate phenotypic analysis and interpretation of developmental behavior of the injected embryos. Furthermore, in this study, spare IVM human oocytes were used, which may not recapitulate the developmental behavior of in vivo matured oocytes.

WIDER IMPLICATIONS OF THE FINDINGS

Comparison of developmental competency following CRISPR-Cas-mediated gene targeting in mouse and human may be influenced by the selected mouse strain. Gene targeting by CRISPR-Cas9 is subject to variable targeting efficiencies. Therefore, striving to reduce mosaicism can provide novel molecular insights into mouse and human embryogenesis.

STUDY FUNDING/COMPETING INTEREST(S)

The research was funded by the Ghent University Hospital and Ghent University and supported by the FWO-Vlaanderen (Flemish fund for scientific research, Grant no. G051516N), and Hercules funding (FWO.HMZ.2016.00.02.01). The authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Ubiquitylation in DNA double-strand break repair

Genome integrity is constantly challenged by various DNA lesions with DNA double-strand breaks (DSBs) as the most cytotoxic lesions. In order to faithfully repair DSBs, DNA damage response (DDR) signaling networks have evolved, which organize many multi-protein complexes to deal with the encountered DNA damage. Spatiotemporal dynamics of these protein complexes at DSBs are mainly modulated by post-translational modifications (PTMs). One of the most well-studied PTMs in DDR is ubiquitylation which can orchestrate cellular responses to DSBs, promote accurate DNA repair, and maintain genome integrity. Here, we summarize the recent advances of ubiquitin-dependent signaling in DDR and discuss how ubiquitylation crosstalks with other PTMs to control fundamental biological processes in DSB repair.

CircRNA UBAP2 facilitates the progression of colorectal cancer by regulating miR-199a/VEGFA pathway

OBJECTIVE

The aim of this study is to explore the regulatory mechanism of circRNA UBAP2 (circUBAP2) in colorectal cancer (CRC).

PATIENTS AND METHODS

The expression levels of circUBAP2, miR-199a, and VEGFA in tissues and cell lines were detected by RT-qPCR. The cell proliferation was examined by CCK-8 and colony formation assays. The migration and invasion abilities were evaluated by wound healing and transwell assays, respectively. Bioinformatics analysis and Luciferase activity assay were applied to determine the interaction between genes.

RESULTS

The expression of circUBAP2 was upregulated in CRC tissues and cell lines, and depletion of circUBAP2 suppressed the cell proliferation, migration, and invasion of CRC. Furthermore, miR-199a inhibitor abrogated the suppressive effect of circUBAP2 knockdown on CRC progression. Vascular endothelial growth factor A (VEGFA) was identified as a downstream target gene of miR-199a, and overexpression of VEGFA rescued the tumor phenotypes attenuated by circUBAP2 knockdown or miR-199a overexpression.

CONCLUSIONS

Our findings demonstrated that circUBAP2 facilitated CRC progression by sponging miR-199a to upregulate VEGFA. These findings implied that circUBAP2 may be a potential therapeutic biomarker for CRC.