Circular RNA expression profiles in human bronchial epithelial cells treated with beryllium sulfate

Circular RNAs (circRNAs), is a novel type of endogenous non-coding RNAs (ncRNAs) participated in the pathogenesis of many diseases. Beryllium is one of the carcinogenesis elements. However, the mechanism and function of circRNAs in human bronchial epithelial cells (16HBE) induced by beryllium sulfate (BeSO₄) was rarely reported. Therefore, the high-throughput RNA sequencing analysis was performed to detect the circRNA profiles between control groups and BeSO₄-induced groups. Furthermore, circRNA-miRNA-mRNA network, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and PPI network analysis were used for bioinformatics analysis. CircRNA sequencing analysis revealed that 36 circRNAs were up-regulated and 35 circRNAs were down-regulated in the BeSO₄-exposed groups. The selected circRNAs were verified by real-time fluorescent quantitative PCR (qRT-PCR). Hsa_circ_0004214 and hsa_circ_0003586 were validated to be up-regulated, hsa_circ_0047958, hsa_circ_0001944, and hsa_circ_0008982 were down-regulated. The circRNA-miRNA-mRNA network annotated the key signaling pathway including cellular senescence, TNF signaling pathway, NF-kappa B signaling pathway, HIF-1 signaling pathway, and Hippo signaling pathway. The PPI network indicated the most circRNAs might participate in the BeSO₄ toxicity by acting as a sponge for the miR-663b through JAK-STAT signaling pathway. In summary, our study suggests that circRNAs may play roles in the mechanism of beryllium toxicity.

Characterization of CwlC, an autolysin, and its role in mother cell lysis of Bacillus thuringiensis subsp. israelensis

Bacillus thuringiensis subsp. israelensis (Bti) has been proven to efficiently control mosquitoes, of which many species are important vectors of human disease. The larvicidal action is attributed to the parasporal crystals formed in the sporulating cells and released upon cell autolysis. In this study, a sporulation-specific cwlC gene that encodes an N-acetylmuramoyl-_L -alanine amidase was characterized in Bti strain Bt-59. CwlC was the only cell wall hydrolase in Bti found to contain both MurNAc-LAA and Amidase02_C domains. A recombinant CwlC-His protein was able to digest the Bacillus cell wall. Deletion of the cwlC gene delayed Bti mother cell lysis without impacting vegetative growth or insecticidal efficacy. Transcriptional analyses indicated that cwlC was expressed at the late sporulation stage and was controlled by SigK. Two other cell wall hydrolase genes, cwlB and cwlE, with high expression levels at T₁₄ in Bt-59, were also identified. Like cwlC, cwlB expression was controlled by SigK; in contrast, cwlE was found not to be under the control of this sigma factor and unlike the other two, its gene was found to be plasmid encoded.

Taurine Reduces Liver Damage in Non-Alcoholic Fatty Liver Disease Model in Rats by Down-Regulating IL-9 and Tumor Growth Factor TGF-β

The study employed a rat model to examine the effects of taurine (Tau) on prevention and therapy of non-alcoholic fatty liver disease (NAFLD). In model rats maintained on a high-fat diet (HFD), the serum levels of ALT, AST, triglycerides, cholesterol, and LDL were higher than the corresponding levels in normal control and NP groups (p<0.05). In Tau-prevention and Tau-treatment groups, the serum levels of AST and triglycerides were lower than in HFD rats (p<0.05). In HFD rats, diffuse fatty degeneration and infiltration with inflammatory cells was observed in the liver; in the ileal mucosa, the villi were fractured or absent, the epithelium was exfoliated and infiltrated with inflammatory cells. The levels of TGF-β, IL-9, and their mRNA in the liver and ileal mucosa of HFD rats were significantly higher than in normal control and NP groups (p<0.05). In Tau-prevention and Tau-treatment groups, these levels were significantly lower than in HFD rats (p<0.05). Thus, TGF-β and IL-9 can be implicated in NAFLD genesis, while Tau can preventively or therapeutically diminish the damage to the liver and ileal mucosa in rats with this disease by down-regulating the expression of TGF-β and IL-9.

Compound heterozygous KCNV2 variants contribute to cone dystrophy with supernormal rod responses in a Chinese family

Background

Cone dystrophy with supernormal rod response (CDSRR) is an autosomal recessive retinal disorder characterized by myopia, dyschromatopsia, nyctalopia, photophobia, and nystagmus. CDSRR is caused by mutations in KCNV2, the gene encoding for an electrically silent Kv subunit (Kvs) named Kv8.2.

Methods

A Chinese CDSRR family was recruited. Complete ophthalmology clinical examinations were performed to clarify the phenotype. Genetic examination was underwent using whole exome sequencing (WES). In addition, a candidate gene was validated by Sanger sequencing. Expression analysis in vitro including immunoblotting, quantitative real‐time PCR (qRT‐PCR), and co‐immunoprecipitation experiments was performed to investigate the pathogenic mechanism of the identified gene variants.

Results

WES identified two KCNV2 heterozygous mutations from the proband. Sanger sequencing validated that the patient's parents had, respectively, carried those two mutations. Further in vitro functional experiments indicated that the mutated alleles had led the Kv8.2 proteins to fail in expressing and interacting with the Kv2.1 protein, respectively.

Conclusions

This study expanded the KCNV2 mutation spectrum. It can also be deduced that CDSRR has a broad heterogeneity. It is further confirmed that the inability expression of Kv8.2 proteins and the failure of Kv8.2 proteins to interact with Kv2.1 may have accounted for the etiology of CDSRR based on previous studies and this study.

A clinical characteristics and genetic analysis of a case of Rubinstein-Taybi syndrome with glaucoma

The aim of this study was to analyze the clinical features of a Rubinstein-Taybi syndrome (RSTS) case with neonatal glaucoma. We also wanted to explore the manifestation of the disease in combination with genotype-phenotype correlation. For DNA extraction we used 2 ml peripheral blood, collected from the child and parents. The extracted genomic DNA was used for clinical exome sequencing. A 38-day old baby boy was diagnosed with congenital glaucoma on the third day after birth with symptoms, including choking milk, feeding difficulties and slow weight gain. He was admitted to the neonatology department because of lung infection. The clinical exome sequencing showed that the child has a c.2368C>T heterozygous mutation in exome 13 in CREBBP (cAMP responsive element binding protein) while his parents have no such mutation. Combining genetic data with the clinical features, this infant was diagnosed with RSTS. This is the first report of RSTS caused by a c. 2368C>T mutation in CREBBP. RSTS is an extremely rare disease with extensive clinical manifestations. It is highly overlapped with other syndromes which makes the diagnosis difficult. RSTS is easy to be missed or misdiagnosed due to the lack of specific clinical manifestations during the neonatal period. Neonatal specialists need to enhance their awareness and recognition of this condition, and use genetic testing as an effective tool in order to finalize their diagnosis.

[Application value of three-dimensional reconstruction in preoperative evaluation of precise hepatectomy for complex primary liver cancer]

Objective: To explore the application value of three-dimensional reconstruction of liver based on computer software in preoperative evaluation of precise hepatectomy for complex primary liver cancer. Methods: The clinical data of patients in Peking University People's Hospital Hepatobiliary surgery with complicated primary liver cancer from September 17, 2019 to December 20, 2020 were analyzed retrospectively. Preoperative enhanced CT/MR data of patients were collected, and 3D reconstruction of liver was performed in IQQA􀳏-3D Liver system. The liver volume of patients was calculated, the size and location of tumor were described, and the relationship between tumor and intrahepatic bile duct, portal vein, hepatic artery and inferior vena cava was described. Preoperative decision-making and treatment plan were made to compare the compliance of the actual operation plan with the planned operation plan under the guidance of three-dimensional reconstruction. Results: Among all 10 patients, there were 6 males and 4 females, aged 36 to 75 years. There were 6 cases of Child-Pugh grade A and 4 cases of B liver function. There were 5 cases of portal vein variation and 5 cases of hepatic artery variation. The range and M(Q₁,Q₃)of actual liver volume measured by 3D reconstruction in 10 patients was 895- 2 477 cm³ and [1 444(1 001, 1 854)] cm³;the nodule volume was 7-1 808 [133(50, 566)] cm³;the nodule volume in the liver was 0.8%-73.0% [11.0(3.3,32.7)]% and the number of suspected lesions was 1-7. In the end, 6 patients received surgical treatment;3 received chemotherapy, and 1 received conservative treatment. The preoperative three-dimensional reconstruction of liver anatomy and tumor location of the patients receiving surgical treatment were basically consistent with the intraoperative situation. There was no case of liver failure or death during perioperative period. Conclusion: In the preoperative evaluation of precise hepatectomy for complex primary liver cancer, 3D reconstruction can improve the rationality of treatment and the surgeon's understanding of the anatomical characteristics of the liver, so as to select the best treatment for patients, which has great application value.

Nontarget and high-throughput screening of pesticides and metabolites residues in tea using ultra-high-performance liquid chromatography and quadrupole-orbitrap high-resolution mass spectrometry

A Sin-QuEChERS, coupled to UHPLC Q-Exactive Orbitrap MS, was used for nontargeted high-throughput rapid screening and quantitative analysis of residual pesticides and metabolites in green teas. The sample was extracted with 0.1% formic acid in acetonitrile with shaking, salted out and centrifuged, and purified with Sin-QuEChERS Nano solid phase extraction column; with Full MS/ddMS2 as the data collection mode, the database containing 384 pesticides combined with Trace Finder 3.0 software, In the absence of standard products, rapid screening and confirmation of potential pesticide residues in tea samples with accurate mass, isotope abundance ratio, secondary fragment ions, etc. 20 pesticides were used as quality controls to verify the screening method, and the linearity of these pesticides was between 1 and 200 μg/L, and the correlation coefficients were all greater than 0.9922. Moreover, the LOQ was between 0.002 and 0.01 mg/kg. The average recoveries of spiked tea samples were 74%-111%. Efficiency and reliability of this method were investigated by the analysis of 38 Chinese green tea samples. 18 potential residual pesticides were detected by non-targeted screening. The researchers then conducted a quantitative analysis of the 18 potential residual pesticides.

Accurate prediction and genome-wide association analysis of digital intramuscular fat content in longissimus muscle of pigs

Intramuscular fat (IMF) content is a critical indicator of pork quality that affects directly the purchasing desire of consumers. However, to measure IMF content is both laborious and costly, preventing our understanding of its genetic determinants and improvement. In the present study, we constructed an accurate and fast image acquisition and analysis system, to extract and calculate the digital IMF content, the proportion of fat areas in the image (PFAI) of the longissimus muscle of 1709 animals from multiple pig populations. PFAI was highly significantly correlated with marbling scores (MS; 0.95, r²  = 0.90), and also with IMF contents chemically defined for 80 samples (0.79, r²  = 0.63; more accurate than direct analysis between IMF contents and MS). The processing time for one image is only 2.31 s. Genome-wide association analysis on PFAI for all 1709 animals identified 14 suggestive significant SNPs and 1 genome-wide significant SNP. On MS, we identified nine suggestive significant SNPs, and seven of them were also identified in PFAI. Furthermore, the significance (-log P) values of the seven common SNPs are higher in PFAI than in MS. Novel candidate genes of biological importance for IMF content were also discovered. Our imaging systems developed for prediction of digital IMF content is closer to IMF measured by Soxhlet extraction and slightly more accurate than MS. It can achieve fast and high-throughput IMF phenotype, which can be used in improvement of pork quality.

FOXN2 suppresses the proliferation and invasion of human hepatocellular carcinoma cells

OBJECTIVE

The aim of this study was to explore the roles of FOXN2 (Fork head Box N2) in mediating the proliferation and invasion of hepatocellular carcinoma (HCC) cells.

PATIENTS AND METHODS

Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was used to determine expression of FOXN2 in HCC tissues and cells. Transfection of plasmid containing FOXN2 was used to exogenously overexpress FOXN2 in vitro. Cell Counting Kit-8 (CCK-8) assay and transwell assay were applied to detect the proliferation and invasion of HCC cells, respectively.

RESULTS

FOXN2 expression decreased significantly in both HCC tissues and cells (p<0.05). Upregulation of FOXN2 significantly inhibited the proliferation and invasion of HCC cells (p<0.05).

CONCLUSIONS

FOXN2 acts as a regulator in the progression of HCC. Our findings suggest that FOXN2 may be a novel therapeutic monitoring and prognosis biomarker in HCC.

Relationship between electrocardiographic changes and EPO level in stable CAD patients with autonomic nerve functional damage

OBJECTIVE

To investigate the relationship between electrocardiographic changes and erythropoietin (EPO) level in stable coronary artery disease (CAD) patients with autonomic nerve functional damage.

PATIENTS AND METHODS

Clinical data of 96 stable CAD patients who were treated in our hospital from January 2017 to December 2019 were retrospectively analyzed. All patients were grouped according to whether autonomic nerve function damage was combined; the baseline characteristic data and the morphological characteristics of ECG scattergram were compared between 2 groups, and the relationship between ECG scattergram and EPO level & autonomic nerve function was analyzed.

RESULTS

The levels of EPO and red cell volume distributing width (RDW) in stable CAD patients with autonomic nerve dysfunction were significantly higher than that of CAD patients without autonomic nerve dysfunction (p<0.05). The length of scattergram in stable CAD patients with autonomic nerve dysfunction was significantly shorter than that of those without autonomic nerve dysfunction (p<0.05). The cometary sign proportion of ECG scattergram in stable CAD patients with autonomic nerve dysfunction was significantly lower than that of stable CAD patients without autonomic nerve dysfunction (p<0.05). There was negative correlation between EPO levels and scattergram length in stable CAD patients with and without autonomic nerve dysfunction (r=0.44, p=0.02). There was no correlation between EPO levels and scatter width in stable CAD patients with and without autonomic nerve dysfunction (r=0.10, p=0.58). The results of binary logistic regression analysis showed that EPO level was the independent risk factor for the occurrence of autonomic dysfunction in patients with stable CAD (p<0.05). The length of scattergram was the independent protective factor of autonomic nerve function impairment in patients with stable CAD (p<0.05). The AUC of EPO level and scattergram was 0.74 and 0.72 respectively, both of which have similar prediction value.

CONCLUSIONS

The level of EPO in stable CAD patients with autonomic nerve dysfunction was related to the change of ECG; and the EPO level and scattergram length can be used to predict the occurrence risk of autonomic nerve dysfunction.

Hydrogen sulfide alleviates apoptosis and autophagy induced by beryllium sulfate in 16HBE cells

Beryllium and its compounds are systemic toxicants that are widely applied in many industries. Hydrogen sulfide has been found to protect cells. The present study aimed to determine the protective mechanisms involved in hydrogen sulfide treatment of 16HBE cells following beryllium sulfate-induced injury. 16HBE cells were treated with beryllium sulfate doses ranging between 0 and 300 μM BeSO₄ . Additionally, 16HBE cells were subjected to pretreatment with either a 300 μM dose of sodium hydrosulfide (a hydrogen sulfide donor) or 10 mM DL-propargylglycine (a cystathionine-γ-lyase inhibitor) for 6 hr before then being treated with 150 μM beryllium sulfate for 48 hr. This study illustrates that beryllium sulfate induces a reduction in cell viability, increases lactate dehydrogenase (LDH) release, and increases cellular apoptosis and autophagy in 16HBE cells. Interestingly, pretreating 16HBE cells with sodium hydrosulfide significantly reduced the beryllium sulfate-induced apoptosis and autophagy. Moreover, it increased the mitochondrial membrane potential and alleviated the G2/M-phase cell cycle arrest. However, pretreatment with 10 mM DL-propargylglycine promoted the opposite effects. PI3K/Akt/mTOR and Nrf2/ARE signaling pathways are also activated following pretreatment with sodium hydrosulfide. These results indicate the protection provided by hydrogen sulfide in 16HBE cells against beryllium sulfate-induced injury is associated with the inhibition of apoptosis and autophagy through the activation of the PI3K/Akt/mTOR and Nrf2/ARE signaling pathways. Therefore, hydrogen sulfide has the potential to be a promising candidate in the treatment against beryllium disease.

POS0885 HIGH INCIDENCE AND MORTALITY OF PNEUMOCYSTIS JIROVECI INFECTION IN ANTI-MDA5-ANTIBODY POSITIVE DERMATOMYOSITIS: EXPERIENCE FROM A SINGLE CENTER

Background:

Idiopathic inflammatory myopathies (IIM) was associated with a significantly higher risk of opportunistic infections that including Pneumocystis jiroveci pneumonia(PJP) which is potentially fatal opportunistic infection. However, no prior studies have evaluated the PJP infection in subtypes of IIM.

Objectives:

To investigate the incidence rate and mortality rate of PJP infection in subgroups of IIM patients according to myopathy specific antibodies.

Methods:

In the first part, we reviewed 463 consecutive patients with IIM retrospectively to analyze incidence of PJP infection. In the next part, we enrolled 30 consecutive PJP infection patients with any rheumatic disease was to identify the mortality rate and risk factors. Kaplan-Meier curve with log rank test was used to access differences in survival. Univariate and multivariate analyses were performed to identify prognostic factors using Cox regression.

Results:

We found that 12(7.5%) PJP cases occurred in 160 anti-MDA5-ab-positive DM patients, while only two (0.7%) PJP cases were found in 303 anti-MDA5-ab-negtive DM/PM patients(P < 0.05). PJP infection typically happened in the first two months of the treatment for anti-MDA5-ab-positive DM patients who have a significant decrease in the CD4+ T cell counts and Lymphocyte counts (P < 0.05). Only two (16.7%) anti-MDA5-ab-positive DM patients recover from PJP, with lethally higher mortality than those PJP infection with other rheumatic diseases (83.3% vs. 38.9%, P < 0.05). We found no association between the time to anti-PJP treatment and treatment outcomes in anti-MDA5-ab-positive DM; yet we confirmed in PJP infection with other rheumatic diseases that anti-PJP treatment within 6 days crucially increased the survival (P < 0.05).

Conclusion:

PJP infection has alarming high incidence and mortality in anti-MDA5-ab-positive DM patients. Unlike PJP infection with other rheumatic diseases, timely treatment for PJP doesn’t improve the prognosis of this particular subtype. Therefore, the necessity of further study of PJP prophylaxis treatment in anti-MDA5-ab-positive DM patients is verified.

References:

[1]Hsu CY, et al. Comparing the burdens of opportunistic infections among patients with systemic rheumatic diseases: a nationally representative cohort study. ARTHRITIS RES THER 2019, 21(1):211.

Acknowledgements:

The authors thank Dr. An Sun,

Disclosure of Interests:

None declared

POS0785 CHANGING EXPRESSION PROFILES OF LONG NONCODING RNAS, MIRNAS, MRNAS AND CIRCULAR RNAS IN LABIAL SALIVARY GLANDS OF PRIMARY SJÖGREN’S SYNDROME (PSS)

Background:

Primary Sjögren’s syndrome (pSS) is a relatively common autoimmune disease characterized by oral and ocular dryness. An increasing number of studies have revealed that long non-coding RNA (lncRNA), miRNA, mRNA and circular RNA (circRNA) contributes to the pathogenesis of autoimmune diseases.

Objectives:

To explore lncRNA, miRNA, mRNA and circRNA expression profiles in labial salivary glands (LSGs) in pSS patients and their biological functions in the regulation of pSS.

Methods:

The expression of 75,550 lncRNAs, 2,318 miRNA, 20,292 mRNAs and 6,877 circRNAs were determined in the LSG of six pSS patients and six healthy controls using microarray experiments. Validation was performed in pSS patients and controls using real-time PCR. LncRNA-mRNA co-expression and gene-pathway networks were constructed using bioinformatics software.

Results:

A total of 599 lncRNAs (upregulated: 279, downregulated: 320), 78 miRNAs (upregulated: 26, downregulated: 52), 615 mRNAs (upregulated: 590, downregulated: 25) and 160 mRNAs (upregulated: 110, downregulated: 50) were differentially expressed in the LSGs of pSS patients. Five of these lncRNAs were validated using real-time PCR. lncRNA HCP5, lncRNA SNHG5, lncRNA IFI44L, lncRNA CMPK2 were significantly upregulated and lncRNA TTYH1 were downregulated in pSS. GO and KEGG biological pathway analysis were performed to predict the functions of differentially expressed lncRNAs and co-expressed potential targeting genes. Subsequently, a ceRNA (lncRNA-miRNA-mRNA) network including 2320 ceRNA pairs was constructed based on predicted miRNAs shared by lncRNAs and mRNAs.

Conclusion:

The expression profile provided a systematic perspective on the potential functions of lncRNAs miRNAs, mRNAs and circRNAs in the pathogenesis of pSS. Therefore, this study will aid in the development of new diagnostic biomarkers and drug therapies.

References:

[1]Le Dantec C, Varin MM, Brooks WH, Pers JO, Youinou P, Renaudineau Y. Epigenetics and Sjogren’s syndrome.Curr Pharm Biotechnol. 2012 Aug;13(10):2046-53.

Disclosure of Interests:

None declared

Association between serum estradiol levels prior to progesterone administration in artificial frozen-thawed blastocyst transfer cycles and live birth rate: a retrospective study

OBJECTIVE

To study whether serum estradiol (E2) levels prior to progesterone administration in the artificial endometrial preparation (AEP) of frozen-thawed blastocyst transfer affect the live birth rate.

DESIGN

Retrospective cohort study.

SETTING

Tertiary-care academic medical centre.

POPULATION

A total of 3857 frozen-thawed blastocyst transfer cycles were divided into three groups: <200 pg/ml (n = 1676); 200-399 pg/ml (n = 1296); and ≥400 pg/ml (n = 885), based on the 25th (182.3 pg/ml) and 75th percentile (390.2 pg/ml) of serum E2 level prior to progesterone administration.

METHODS

Univariable and multivariable logistic regression analysis was performed.

MAIN OUTCOME MEASURES

The primary outcome of the study was the live birth rate and the secondary outcomes included clinical pregnancy rate, pregnancy loss rate, neonatal birthweight, Z-score, and small for gestational age (SGA).

RESULTS

Compared with the reference group, accounting for major covariates, the live birth rate significantly decreased in the '≥400 pg/ml' group (adjusted OR 0.71, 95% CI 0.59-0.85). Compared with the reference group, there was an association between the E2 level in the '≥400 pg/ml' group and a decrease in the clinical pregnancy rate (adjusted OR 0.74, 95% CI 0.61-0.89). Compared with the reference group, the pregnancy loss rate significantly increased in the '≥400 pg/ml' group (adjusted OR 1.45, 95% CI 1.08-1.93). The E2 levels did not affect neonatal birthweight, Z-score, and SGA among singletons.

CONCLUSIONS

High serum E2 levels prior to progesterone administration in AEP are associated with a decreased live birth rate after frozen-thawed blastocyst transfer.

TWEETABLE ABSTRACT

High serum E2 levels prior to progesterone administration in artificial FET are associated with a decreased live birth rate after frozen-thawed blastocyst transfer.

Pcsk9 Knockout Aggravated Experimental Apical Periodontitis via LDLR

Apical periodontitis (AP), an inflammatory lesion around the apex of tooth roots, is mostly caused by dental pulp infection. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a vital role in regulating cholesterol homeostasis by targeting low-density lipoprotein receptor (LDLR) and participates in bacterium-induced chronic periodontitis. However, the roles of PCSK9 in AP are unknown. Here, we investigated its role in AP by using Pcsk9^-/- mice. Micro-computed tomography scanning and histological staining revealed that the periapical bone loss of Pcsk9^-/- mice was greater than that of wild-type (WT) mice, and increased expression of inflammation-related factors tumor necrosis factor α (TNF-α) and interleukin (IL)-6 was also observed. Immunofluorescence staining and quantitative real-time polymerase chain reaction showed PCSK9 expression in bone marrow macrophages (BMMs) was increased after treatment with lipopolysaccharide (LPS). This finding was consistent with the in vivo results that the expression level of PCSK9 in exposed WT mice increased compared with that in unexposed WT mice. After LPS challenge, the expression levels of TNF-α, IL-1β, and IL-6 in BMMs were increased, and Pcsk9 knockout aggravated the expression of these inflammatory factors. The number of osteoclasts positive for tartrate-resistant acid phosphatase staining around the apical lesion in Pcsk9^-/- mice was higher than that in WT mice. Then BMMs underwent the osteoclast differentiation. Pcsk9 knockout BMMs induced increased and larger osteoclasts. While this effect of Pcsk9 knockout was abolished by the addition of Ldlr small interfering RNA, revealing that Pcsk9 knockout increased osteoclastogenesis was dependent on the LDLR. Immunohistochemistry staining showed increased expression level of LDLR in exposed Pcsk9^-/- periapical areas. In vitro experiments showed that LPS promoted the expression level of LDLR in Pcsk9^-/- BMMs and increased osteoclast formation ability, indicating that LPS promoted the elevation of osteoclasteogenesis caused by the Pcsk9 knockout. In conclusion, Pcsk9 deficiency aggravated the inflammatory response and promoted the osteoclastogenesis in an LDLR-dependent manner in AP experimental mice.