SARS-CoV-2 infected cells sprout actin-rich filopodia that facilitate viral invasion

Emerging COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a great threat to human health and economics. Although SARS-CoV-2 entry mechanism has been explored, little is known about how SARS-CoV-2 regulates the host cell remodeling to facilitate virus invasion process. Here we unveil that SARS-CoV-2 boosts and repurposes filopodia for entry to the target cells. Using SARS-CoV-2 virus-like particle (VLP), real-time live-cell imaging and simulation of active gel model, we reveal that VLP-induced Cdc42 activation leads to the formation of filopodia, which reinforce the viral entry to host cells. By single-particle tracking and sparse deconvolution algorithm, we uncover that VLP particles utilize filopodia to reach the entry site in two patterns, surfing and grabbing, which are more efficient and faster than entry via flat plasma membrane regions. Furthermore, the entry process via filopodia is dependent on the actin cytoskeleton and actin-associated proteins fascin, formin, and Arp2/3. Importantly, either inhibition the actin cross-linking protein fascin or the active level of Cdc42 could significantly hinders both the VLP and the authentic SARS-CoV-2 entry. Together, our results highlight that the spatial-temporal regulation of the actin cytoskeleton by SARS-CoV-2 infection makes filopodia as a highway for virus entry, which emerges as an antiviral target. Significance StatementRevealing the mechanism of SARS-CoV-2 invasion is of great significance to explain its high pathogenic and rapid transmission in the world. We discovered a previously unknown route of SARS-CoV-2 entry. SARS-CoV-2 virus-like particles boost cellular filopodia formation by activating Cdc42. Using state-of-art-technology, we spatial-temporally described how virus utilize filopodia to enter the target cell in two modes: surfing and grabbing. Filopodia can directly transport the virus to endocytic hot spots to avoid the virus from disorderly searching on the plasma membrane. Our study complements current knowledge of SARS-CoV-2 that filopodia and its components not only play an important role in virus release and cell-cell transmission, but also in the entry process, and provides several potential therapeutic targets for SARS-CoV-2. HighlightsO_LISARS-CoV-2 VLP infection promotes filopodia formation by activating Cdc42 C_LIO_LISARS-CoV-2 VLP utilizes filopodia to enter target cell via two modes, surfing and grabbing C_LIO_LIFilopodia disruption compromises the invasion of both VLP and authentic SARS-CoV-2 C_LI

Organizing Pneumonia of COVID-19: Time-dependent Evolution and Outcome in CT Findings

ObjectiveAs a pandemic, a most-common pattern resembled organizing pneumonia (OP) has been identified by CT findings in novel coronavirus disease (COVID-19). We aimed to delineate the evolution of CT findings and outcome in OP of COVID-19. Materials and Methods106 COVID-19 patients with OP based on CT findings were retrospectively included and categorized into non-severe (mild/common) and severe (severe/critical) groups. CT features including lobar distribution, presence of ground glass opacities (GGO), consolidation, linear opacities and total severity CT score were evaluated at three time intervals from symptom-onset to CT scan (day 0-7, day 8-14, day>14). Discharge or adverse outcome (admission to ICU or death), and pulmonary sequelae (complete absorption or lesion residuals) on CT after discharge were analyzed based on the CT features at different time interval. Results79(74.5%) patients were non-severe and 103(97.2%) were discharged at median day 25 (range, day 8-50) after symptom-onset. Of 67 patients with revisit CT at 2-4 weeks after discharge, 20(29.9%) had complete absorption of lesions at median day 38 (range, day 30-53) after symptom-onset. Significant differences between complete absorption and residuals groups were found in percentages of consolidation (1.5% vs. 13.8%, P=0.010), number of involved lobe >3 (40.0% vs. 72.5%, P=0.030), CT score >4 (20.0% vs. 65.0%, P=0.010) at day 8-14. ConclusionsMost OP cases had good prognosis. Approximately one-third of cases had complete absorption of lesions during 1-2 months after symptom-onset while those with increased frequency of consolidation, number of involved lobe>3, and CT score >4 at week 2 after symptom-onset may indicate lesion residuals on CT.

A pattern categorization of CT findings to predict outcome of COVID-19 pneumonia

AbstractsO_ST_ABSPurposeC_ST_ABSAs global healthcare system is overwhelmed by novel coronavirus disease (COVID-19), early identification of risks of adverse outcomes becomes the key to optimize management and improve survival. This study aimed to provide a CT-based pattern categorization to predict outcome of COVID-19 pneumonia. Methods165 patients with COVID-19 (91 men, 4-89 years) underwent chest CT were retrospectively enrolled. CT findings were categorized as Pattern0 (negative), Pattern1 (bronchopneumonia), Pattern2 (organizing pneumonia), Pattern3 (progressive organizing pneumonia) and Pattern4 (diffuse alveolar damage). Clinical findings were compared across different categories. Time-dependent progression of CT patterns and correlations with clinical outcomes, i.e. discharge or adverse outcome (admission to ICU, requiring mechanical ventilation, or death), with pulmonary sequelae (complete absorption or residuals) on CT after discharge were analyzed. ResultsOf 94 patients with outcome, 81(86.2%) were discharged, 3(3.2%) were admitted to ICU, 4(4.3%) required mechanical ventilation, 6(6.4%) died. 31(38.3%) had complete absorption at median day 37 after symptom-onset. Significant differences between pattern-categories were found in age, disease-severity, comorbidity and laboratory results (all P<0.05). Remarkable evolution was observed in Pattern0-2 and Pattern3-4 within 3 and 2 weeks after symptom-onset, respectively; most of patterns remained thereafter. After controlling for age, CT pattern significantly correlated with adverse outcomes (Pattern4 vs. Pattern0-3 [reference]; hazard-ratio[95%CI], 18.90[1.91-186.60], P=0.012). CT pattern (Pattern3-4 vs. Pattern0-2 [reference]; 0.26[0.08-0.88], P=0.030) and C-reactive protein (>10 vs. [≤]10mg/L [reference]; 0.31[0.13-0.72], P=0.006) were risk-factors associated with pulmonary residuals. ConclusionCT pattern categorization allied with clinical characteristics within 2 weeks after symptom-onset would facilitate early prognostic stratification in COVID-19 pneumonia.

Research status of tooth preparation quantitative guide technique / 中华口腔医学杂志

Tooth preparation is a basic operation in prosthodontics treatment and the quality of preparation influences the effect of treatment directly. How to achieve a precise and quantitative tooth preparation is always one of the main aims of dental prosthodontics. The known types of tooth preparation guide technique can be divided into visual guidance, passive constraint guidance and active constraint guidance (automated tooth preparation), respectively represented by silicon rubber index, tooth preparation guide plate and computerized numerical control cutting system (CNC cutting system). Studies in advanced manufacturing technologies such as robot systems and numerical control ultra-short pulse laser (USPL) have also been reported recently. This review comprehensively introduced tooth preparation quantitative guide techniques and partially summarized the application effects and limitations to provide reference for relative researches and clinical application.

Tooth separation from dental model using segmentation field.

Tooth segmentation on dental model is an essential step of computer-aided-design systems for orthodontic virtual treatment planning. However, efficiently identifying cutting boundary to separate tooth from dental model still remains a challenge, due to various geometrical shapes of teeth, complex tooth arrangements and varying degrees of crowding problem. Most segmentation approaches presented before are not able to achieve a balance between fine segmentation results and simple operating procedure. In this article, we present a novel and efficient framework that achieves tooth segmentation based on the segmentation field. Specially, the candidate cutting boundaries are able to be detected from the concave regions with large variations of field data. The sensitivity to concave seams of segmentation field facilitates effective tooth partition, as well as avoids obtaining appropriate curvature threshold value, which is unreliable in some case. The experiments indicate that, our tooth segmentation algorithm is robust to different dental models with severe crowding problems and poor distinction.

Efficacy and safety of ultrasound-guided upper-pole access percutaneous nephrolithotomy for the treatment of renal staghorn calculi / 局解手术学杂志

s: Objective To investigate the efficacy and safety of ultrasound-guided upper-pole access percutaneous nephrolithotomy (PCNL) for the treatment of renal staghorn calculi. Methods From October 2008 to July 2012,193 cases of renal staghorn calculi treated with ultrasound-guided upper-pole access PCNL were reviewed. Among the 193 cases,74 cases were complete staghorn calculi while the other 119 cases were partial staghorn calculi, and the calculi diameter was 2. 5 to 9. 0 cm. All the 193 cases were treated through upper-pole ac-cess successfully,70 accesses were accomplished below the 12th rib,while the other 123 accesses were accomplished between the 11th adn 12th rib. Disintegration of the stone was accomplished using Holmium laser. Results The mean operative time was 70 min (45~150 min), single tract was used in 186 cases, and double tracts were used in the other 7 cases. The stone clearance rate for one session was 72. 0%(139/193),and the total stone clearance rate was 88. 1%(170/193). Transfusion was required in 6 patients, while 2 patients with signifi-cant bleeding were treated with selective renal arterial embolization. Hydrothorax occured in 4 patients, and closed thoracic drainage was re-quired in 2 of them. 20 patients had fever, and they recovered after effective antibiotic treatment. No patients had injury to the lung or other viscera. Conclusion Upper-pole access offers optimal visibility and convenience for rigid ureteroscope to achieve a high rate of stone-free status and operating time reduce. Ultrasound guided upper-pole access PCNL should be attempted in selected cases of renal staghorn stone.

Mapping the interaction site of prion protein and Sho.

The cellular prion protein (PrP(C)) is a highly conserved protein among mammals and is considered to have important cellular functions. Despite decades of intensive research, however, the physiological function of PrP(C) remains unclear. Sho (Shadoo, shadow of prion protein) and PrP(C) have similar N-terminals, which suggests that the two proteins share biological functions. Using truncation mutants of both proteins and yeast two-hybrid analysis, with validation by co-immunoprecipitation and surface plasmon resonance (SPR), we have identified an interaction between Sho 61-77 and PrP(C) 108-126 domains. This indicates that Sho may play a role in the physiological function of PrP(C) and prion pathogenesis.

Expression of H5N1 avian influenza virus haemagglutinin protein in pichia pastoris by high-density cell fermentation / 生物工程学报

We produced high pathogenic avian influenza H5N1 haemagglutinin protein HA1 in recombinant Pichia pastoris in a 10 L fermentor, to establish a high-density cell fermentation method. We studied the effects of different factors such as culture temperature, induced temperature, methanol feeding methods, trace elements on the growth of Pichia pastoris, the yield and the biologic activity of recombinant HA1 protein. The culture temperature in pre-induced and induced stage were optimized at 25 degrees C to adapt cell growth and recombinant protein expression, and induced temperature at 25 degrees C also resulted in higher biologic activity of rHA1 than at 30 degrees C. The binding activity of rHA1 against a wide-spectrum neutralizing antibody was susceptible to the presence of any trace elements, although trace elements would essentially benefit for the cell fermentation. As a conclusion, the expression level of rHA1 produced with optimized fermentation process reached 120 mg/L, which was 10.5 times higher than the one produced in regular shaking flask. The resultant high-density cell fermentation can likely produce rHA1 of H5N1 in large scale.

Expression, purification and immunogenicity analysis of HPV type 18 virus-like particles from Escherichia coli / 生物工程学报

Here, we presented a method to bacterially express the major structural protein L1 of Human Papillomavirus type 18 (HPV18) as soluble form. We found that the purified L1 could self-assemble to virus-like particles (VLPs). Further, we investigated the immunogenicity and the induced level of neutralizing antibody using these VLPs. First, the genome of HPV18 was cloned from a patient in Xiamen. It was used as template for PCR amplification of HPV18 L1 gene. The resultant DNA fragment was inserted into expression vector pTrxFus and expressed in Escherichia coli GI724. Second, L1 protein was purified by ammonium sulfate precipitation, ion-exchange chromatography and hydrophobic interaction chromatography; and the purified L1 was subjected to self-assembly to form VLPs with the removal of premixed reductant DTT. Finally, the size and morphology of these VLPs was investigated by Dynamic Light Scattering and Transmission Electronic Microscopy as 29.34 nm in hydrated radius and globular particles similar with native HPV18. The half effective dosage (ED50) and maximum level of neutralizing antibody elicitation were measured by vaccinations on mice, rabbit and goat using pseudovirus neutralization cell model. The results showed that the ED50 of HPV18 VLPs is 0.006 microg in mice, and the maximum titer of neutralizing antibody elicited in rabbit and goat is up to 10(7). As a conclusion, we can provide HPV18 VLPs with highly immunogenicity from prokaryote expression system, which may pave a new way for research and development of prophylactic vaccine for HPV18.

Urinary interleukin-8 and pH changes after intravesical bacillus calmette-guerin therapy for superficial bladder cancer:processing and prognostic value / 中华泌尿外科杂志

Objective To screen for nonresponding cases of superficial transitional cell carcinoma of the bladder at an early stage of intravesical bacillus Calmette Guetin(BCG) therapy. Methods IL 8 and urine pH were assayed both before intravesical BCG instillation and after the 1st and 6th instillation for 32 cases of superficial transitional cell bladder cancinoma following TURB or partial cystectomy.Urinary IL 8 was measumed by chemiluminescence enzyme immunomeric assay and urine pH by routine examination.The result was studied with reference to the clinical outcome of the patients. Results All the patients have been followed up for 6～25 months with tumor recurrence in 5.Urinary IL 8 in these 5 dropped to 161.3?64.5 ng/L after the 1st instillation whereas it was 579.4?77.8 ng/L in the others ( P

An experimental study on inhibiting growth and metastasis of mouse melanoma by engineering endostatin / 细胞与分子免疫学杂志

Aim To explore inhibitory effects and mechanism of engineering endostatin on growth and metastasis of melanoma cells in mice. Methods Melanoma cells(2× 106/mouse)were inoculated sabcutaneously to C57BL/6 mice. After tumorigenesis,endostatin(8mg/kg.d)was administrated to tumor-bearing mice,once a day ,twenty-one in all.Dietetic state and weight change of the tumor-bearing mice were observed and tumorous sige was measured during administration of endostatin. On 26thday,the tumor-bearing mice were sacrificed,subcutaneously tumorous weight was weighed and brain,lung ,liver,spleen and kidney were excised and sections were made to supply the pathological examination. Results Area under curve in the endostatin-treated group was obviously less than that in tamor control group(P∨ 0.01). Pathological study revealed that lavge areal necrosis arose in tumor and newborn cappillaries around the tumor disapeared. Conclusion Endostatin possosses strongly inhibitory effects on growth and metastasis of mouse melanoma and formation of newborn capillaries around tumor.

Expression and Purification of Recombinant Human Endostatin / 中国肿瘤生物治疗杂志

Objective: To highly express rh-Endostatin from Pichia pastoris and purify it to homogeneity. Methods: Constructed Pichia pastoris X33/pLW202 was amplified and inoculated to ferment media. The supernatant of the strain was collected after induction. Through ultrafiltration, affinity and gel chromatography, rh-Endostatin with high purication was obtained. Results: 60mg/L rh-Endostatin was obstained from supernatant. HPLC showed its purity was above 98%. Conclusion: High level expression of secreted rh-Endostatin has been successfully achieved in Pichia pastoris expression system.

Clinical Observation of Possibility of GVHD in Patients Treated by Transfer of Allo-LAK Cells / 中国肿瘤生物治疗杂志

Perepherial blood lymphocytes from normal donors were isolated by Haemonetice V50 Ampheresis System, and incubated in RPMI 1640 contained 1000U/ml rIL-2 and 10%AB serum at 37癈, 5%CO2. Five days later, these cells were harvested and tested their LAK activity. Then 10 patients with malignant metastases were treated by transfer of allo-LAK cells. After 2 and 6 months, the PEL from patients were seperated for the test of response to IL-2, proliferation to ConA and production of IL-2. The result showed that no significantly reducing of these value after patients being treated by Allo-LAK cells. Combined with clinical observation and pathological biopsy, it was concluded that GVHD couldn't be caused by transfer 6f allogenic LAK cells.