Targeting CD38/ ADP-ribosyl cyclase as a novel therapeutic strategy for identification of three potent agonists for leukopenia treatment.

Leukopenia is the most common side effect of chemotherapy and radiotherapy. It potentially deteriorates into a life-threatening complication in cancer patients. Despite several agents being approved for clinical administration, there are still high incidences of pathogen-related disease due to a lack of functional immune cells. ADP-ribosyl cyclase of CD38 displays a regulatory effect on leukopoiesis and the immune system. To explore whether the ADP-ribosyl cyclase was a potential therapeutic target of leukopenia. We established a drug screening model based on an ADP-ribosyl cyclase-based pharmacophore generation algorithm and discovered three novel ADP-ribosyl cyclase agonists: ziyuglycoside II (ZGSII), brevifolincarboxylic acid (BA), and 3,4-dihydroxy-5-methoxybenzoic acid (DMA). Then, in vitro experiments demonstrated that these three natural compounds significantly promoted myeloid differentiation and antibacterial activity in NB4 cells. In vivo, experiments confirmed that the compounds also stimulated the recovery of leukocytes in irradiation-induced mice and zebrafish. The mechanism was investigated by network pharmacology, and the top 12 biological processes and the top 20 signaling pathways were obtained by intersecting target genes among ZGSII, BA, DMA, and leukopenia. The potential signaling molecules involved were further explored through experiments. Finally, the ADP-ribosyl cyclase agonists (ZGSII, BA, and DMA) has been found to regenerate microbicidal myeloid cells to effectively ameliorate leukopenia-associated infection by activating CD38/ADP-ribosyl cyclase-Ca2+-NFAT. In summary, this study constructs a drug screening model to discover active compounds against leukopenia, reveals the critical roles of ADP-ribosyl cyclase in promoting myeloid differentiation and the immune response, and provides a promising strategy for the treatment of radiation-induced leukopenia.

Mapping the risk factors, pathogens, and antibiotic of pharyngocutaneous fistula in patients after neck open surgery.

PURPOSE: Current literature lacks consensus on risk factors for pharyngocutaneous fistula (PCF), and empirical antibiotic guidelines for PCF are limited. The aim of this study was to reduce the incidence of PCF and improve antibiotic treatment efficacy for patients with PCF after open neck surgery by analyzing their clinical characteristics, pathogenic bacteria, and antibiotic susceptibility. METHODS: This study was a 13-year single-center retrospective cohort study, including 699 patients who underwent open neck surgery for laryngeal and hypopharyngeal cancer. Univariate and multivariate logistic regression analyses were conducted to identify the risk factors associated with the occurrence of PCF after surgery. The microbial species causing PCF were analyzed, and the antibiotic sensitivity of the top three pathogens was assessed. Venn diagrams were used to illustrate the antibiotics that exhibited 100% sensitivity against all three identified pathogens. RESULTS: The incidence of PCF after open neck surgery was 8%. Logistic univariate and multivariate analyses revealed that flap reconstruction (OR = 3.62, 95% CI [2.02-6.52]), history of preoperative radiotherapy (OR = 2.01, 95% CI [1.31-2.73]), significant postoperative bleeding (OR = 1.79, 95% CI [1.11-2.69]), and history of diabetes (OR = 1.34, 95% CI [1.29-2.46]) were significantly associated with PCF occurrence. Among the 38 cases of PCF patients, the top three identified pathogens were Pseudomonas aeruginosa, Escherichia coli, and Enterobacter cloacae. The antibiotics cefepime, meropenem, ticarcillin/clavulanic acid, and cefoperazone/sulbactam showed 100% sensitivity against these top three pathogens. CONCLUSION: Special attention should be given to patients undergoing open neck surgery, especially those with intraoperative flap reconstruction, a history of preoperative radiotherapy, postoperative bleeding, or diabetes. Strengthening monitoring and care is crucial in preventing the occurrence of PCF. According to antibiotic usage guidelines and considering the distribution of pathogens in PCF patients, empirical antibiotic treatment with cefoperazone/sulbactam or ticarcillin/clavulanic acid is recommended prior to obtaining susceptibility test results.

Discovery of benzodiazepine derivatives as a new class of covalent inhibitors of SARS-CoV-2 main protease.

The COVID-19 pandemic has caused people immense suffering all over the world. Although the World Health Organization (WHO) has announced the end of the pandemic, the sporadic virus epidemic is still ongoing and may exist permanently. Effective antivirals against SARS-CoV-2 are important to deal with the long-term threat. The main protease (Mpro) is a crucial target for drug development due to its role in the process of virus's replication and transcription. Herein, we report benzodiazepine derivatives as a new class of Mpro inhibitors. Structure-activity relationship (SAR) studies led to the discovery of the most active compound, methyl 10-(2-chloroacetyl)-1-oxo-11-(4-(trifluoromethyl)phenyl)-2,3,4,5,10,11-hexahydro-1H-dibenzo[b,e][1,4]-diazepine-7-carboxylate (11a), which shows an IC50 value of 0.180 ± 0.004 µM. The X-ray crystal structure shows that 11a covalently binds to Mpro. Collectively, we have obtained a new small molecule inhibitor targeting Mpro, which can serve as a lead compound for subsequent drug discovery against SARS-CoV-2.

Duck hepatitis A virus type 1 mediates cell cycle arrest in the S phase.

BACKGROUND: Duck hepatitis A virus type 1 (DHAV-1) is one of the most serious pathogens endangering the duck industry. However, there are few studies on the regulation of the cell cycle by DHAV-1. METHODS: In this study, flow cytometry was applied to analyze the effect of DHAV-1 infection on the cell cycle of duck embryo fibroblasts (DEFs). Subsequently, we analyzed the effects of cell cycle phases on DHAV-1 replication by real-time reverse transcriptase quantitative PCR (real-time RT-qPCR). RESULTS: Flow cytometry data analysis found that DEFs in the S phase increased by 25.85% and 54.21% at 24 h and 48 h after DHAV-1 infection, respectively. The levels of viral RNA detected by real-time RT-qPCR were higher in the DEFs with synchronization in the S phase or G0/G1 phase than in the control group. However, there was no difference in viral copy number between the G2/M phase arrest and control groups. In addition, non-structural protein 3D of DHAV-1 significantly increased cells in the S phase, indicating that 3D protein is one of the reasons for the cell cycle arrest in the S phase. CONCLUSIONS: In summary, DHAV-1 infection induces the cell cycle arrest of DEFs in the S phase. Both S phase and G0/G1 phase synchronization facilitate the replication of DHAV-1, and 3D protein is one of the reasons for the S phase arrest.

Label-free visualization and characterization of extracellular vesicles in breast cancer.

Despite extensive interest, extracellular vesicle (EV) research remains technically challenging. One of the unexplored gaps in EV research has been the inability to characterize the spatially and functionally heterogeneous populations of EVs based on their metabolic profile. In this paper, we utilize the intrinsic optical metabolic and structural contrast of EVs and demonstrate in vivo/in situ characterization of EVs in a variety of unprocessed (pre)clinical samples. With a pixel-level segmentation mask provided by the deep neural network, individual EVs can be analyzed in terms of their optical signature in the context of their spatial distribution. Quantitative analysis of living tumor-bearing animals and fresh excised human breast tissue revealed abundance of NAD(P)H-rich EVs within the tumor, near the tumor boundary, and around vessel structures. Furthermore, the percentage of NAD(P)H-rich EVs is highly correlated with human breast cancer diagnosis, which emphasizes the important role of metabolic imaging for EV characterization as well as its potential for clinical applications. In addition to the characterization of EV properties, we also demonstrate label-free monitoring of EV dynamics (uptake, release, and movement) in live cells and animals. The in situ metabolic profiling capacity of the proposed method together with the finding of increasing NAD(P)H-rich EV subpopulations in breast cancer have the potential for empowering applications in basic science and enhancing our understanding of the active metabolic roles that EVs play in cancer progression.

Single-shot two-dimensional spectroscopic magnetomotive optical coherence elastography with graphics processing unit acceleration.

Biomechanical contrast within tissues can be assessed based on the resonant frequency probed by spectroscopic magnetomotive optical coherence elastography (MM-OCE). However, to date, in vivo MM-OCE imaging has not been achieved, mainly due to the constraints on imaging speed. Previously, spatially-resolved spectroscopic contrast was achieved in a "multiple-excitation, multiple-acquisition" manner, where seconds of coil cooling time set between consecutive imaging frames lead to total acquisition times of tens of minutes. Here, we demonstrate an improved data acquisition speed by providing a single chirped force excitation prior to magnetomotion imaging with a BM-scan configuration. In addition, elastogram reconstruction was accelerated by exploiting the parallel computing capability of a graphics processing unit (GPU). The accelerated MM-OCE platform achieved data acquisition in 2.9 s and post-processing in 0.6 s for a 2048-frame BM-mode stack. In addition, the elasticity sensing functionality was validated on tissue-mimicking phantoms with high spatial resolution. For the first time, to the best of our knowledge, MM-OCE images were acquired from the skin of a living mouse, demonstrating its feasibility for in vivo imaging.

The role of host eIF2α in viral infection.

BACKGROUND: eIF2α is a regulatory node that controls protein synthesis initiation by its phosphorylation or dephosphorylation. General control nonderepressible-2 (GCN2), protein kinase R-like endoplasmic reticulum kinase (PERK), double-stranded RNA (dsRNA)-dependent protein kinase (PKR) and heme-regulated inhibitor (HRI) are four kinases that regulate eIF2α phosphorylation. MAIN BODY: In the viral infection process, dsRNA or viral proteins produced by viral proliferation activate different eIF2α kinases, resulting in eIF2α phosphorylation, which hinders ternary tRNAMet-GTP-eIF2 complex formation and inhibits host or viral protein synthesis. The stalled messenger ribonucleoprotein (mRNP) complex aggregates under viral infection stress to form stress granules (SGs), which encapsulate viral RNA and transcription- and translation-related proteins, thereby limiting virus proliferation. However, many viruses have evolved a corresponding escape mechanism to synthesize their own proteins in the event of host protein synthesis shutdown and SG formation caused by eIF2α phosphorylation, and viruses can block the cell replication cycle through the PERK-eIF2α pathway, providing a favorable environment for their own replication. Subsequently, viruses can induce host cell autophagy or apoptosis through the eIF2α-ATF4-CHOP pathway. CONCLUSIONS: This review summarizes the role of eIF2α in viral infection to provide a reference for studying the interactions between viruses and hosts.

Upregulated circular RNA circ_0025033 promotes papillary thyroid cancer cell proliferation and invasion via sponging miR-1231 and miR-1304.

Recent evidence revealed that circular RNAs (circRNAs) are key regulators for tumorigenesis. However, their roles in papillary thyroid cancer (PTC) is not fully understood. In the current work, the differentially expressed circRNAs between PTC tissues and adjacent noncancerous tissue samples were screened by circRNA microarray. We further selected the highest expressed circRNA (circ_0025033) in tumorous tissues for the study. qRT-PCR was used to measure the level of circ_0025033 in PTC tissue samples and cell lines. Gain/loss of function assays were carried out to determine the effect of circ_0025033 on cell viability, clone-forming, apoptosis, migration and invasion. Dual-luciferase reporter assays were conducted to investigate the mechanisms of circ_0025033 in PTC. The data showed that circ_0025033 aggravated cell proliferation, migration and invasion and inhibited cell apoptosis. Additionally, circ_0025033 could directly sponge miR-1231 and miR-1304 in PTC cells. Furthermore, the oncogenic role of circ_0025033 is dependent on its suppression of miR-1231 and miR-1304. Collectively, this work uncovers a novel signal of circ_0025033/miR-1231/miR-1304 involved in PTC initiation and progression.

Automated sensorless single-shot closed-loop adaptive optics microscopy with feedback from computational adaptive optics.

Traditional wavefront-sensor-based adaptive optics (AO) techniques face numerous challenges that cause poor performance in scattering samples. Sensorless closed-loop AO techniques overcome these challenges by optimizing an image metric at different states of a deformable mirror (DM). This requires acquisition of a series of images continuously for optimization - an arduous task in dynamic in vivo samples. We present a technique where the different states of the DM are instead simulated using computational adaptive optics (CAO). The optimal wavefront is estimated by performing CAO on an initial volume to minimize an image metric, and then the pattern is translated to the DM. In this paper, we have demonstrated this technique on a spectral-domain optical coherence microscope for three applications: real-time depth-wise aberration correction, single-shot volumetric aberration correction, and extension of depth-of-focus. Our technique overcomes the disadvantages of sensor-based AO, reduces the number of image acquisitions compared to traditional sensorless AO, and retains the advantages of both computational and hardware-based AO.

Detection of weak near-infrared optical imaging signals under ambient light by optical parametric amplification.

We present a detection method based on optical parametric amplification to amplify and detect near-infrared (NIR) optical imaging signals. A periodically poled lithium niobate crystal is employed as an optical parametric amplifier (OPA), which provides excellent quasi-phase-matching conditions for the optical parametric amplification process. A weak reflectance imaging signal at 1465 nm is amplified by the OPA with a high gain of up to 92 dB, and the amplified optical signal is detected with a low-cost photodetector under ambient light conditions. Such a high gain leads to a detection limit of 23 pW under a 5 MHz detection bandwidth, which is remarkably lower than the theoretical value of a NIR photomultiplier tube (PMT). By exploiting the advantages of the OPA, the incident power needed for microscopy or imaging is reduced by 40-60 dB. The high imaging gain of the OPA also significantly enhances the imaging penetration depth by selectively detecting the weak signal reflected from deep tissue structures. The successful implementation of the OPA enables a robust and sensitive detection method that offers the potential to replace PMTs in imaging applications within the NIR spectral range.

Local wavefront mapping in tissue using computational adaptive optics OCT.

The identification and correction of wavefront aberrations is often necessary to achieve high-resolution optical images of biological tissues, as imperfections in the optical system and the tissue itself distort the imaging beam. Measuring the localized wavefront aberration provides information on where the beam is distorted and how severely. We have recently developed a method to estimate the single-pass wavefront aberrations from complex optical coherence tomography (OCT) data. Using this method, localized wavefront measurement and correction using computational OCT was performed in ex vivo tissues. The computationally measured wavefront varied throughout the imaged OCT volumes and, therefore, a local wavefront correction outperformed a global wavefront correction. The local wavefront measurement was also used to generate tissue aberration maps. Such aberration maps could potentially be used as a new form of tissue contrast.

Wavefront measurement using computational adaptive optics.

In many optical imaging applications, it is necessary to correct for aberrations to obtain high quality images. Optical coherence tomography (OCT) provides access to the amplitude and phase of the backscattered optical field for three-dimensional (3D) imaging samples. Computational adaptive optics (CAO) modifies the phase of the OCT data in the spatial frequency domain to correct optical aberrations without using a deformable mirror, as is commonly done in hardware-based adaptive optics (AO). This provides improvement of image quality throughout the 3D volume, enabling imaging across greater depth ranges and in highly aberrated samples. However, the CAO aberration correction has a complicated relation to the imaging pupil and is not a direct measurement of the pupil aberrations. Here we present new methods for recovering the wavefront aberrations directly from the OCT data without the use of hardware adaptive optics. This enables both computational measurement and correction of optical aberrations.

Automated computational aberration correction method for broadband interferometric imaging techniques.

Numerical correction of optical aberrations provides an inexpensive and simpler alternative to the traditionally used hardware-based adaptive optics techniques. In this Letter, we present an automated computational aberration correction method for broadband interferometric imaging techniques. In the proposed method, the process of aberration correction is modeled as a filtering operation on the aberrant image using a phase filter in the Fourier domain. The phase filter is expressed as a linear combination of Zernike polynomials with unknown coefficients, which are estimated through an iterative optimization scheme based on maximizing an image sharpness metric. The method is validated on both simulated data and experimental data obtained from a tissue phantom, an ex vivo tissue sample, and an in vivo photoreceptor layer of the human retina.

Computed Optical Interferometric Imaging: Methods, Achievements, and Challenges.

Three-dimensional high-resolution optical imaging systems are generally restricted by the trade-off between resolution and depth-of-field as well as imperfections in the imaging system or sample. Computed optical interferometric imaging is able to overcome these longstanding limitations using methods such as interferometric synthetic aperture microscopy (ISAM) and computational adaptive optics (CAO) which manipulate the complex interferometric data. These techniques correct for limited depth-of-field and optical aberrations without the need for additional hardware. This paper aims to outline these computational methods, making them readily available to the research community. Achievements of the techniques will be highlighted, along with past and present challenges in implementing the techniques. Challenges such as phase instability and determination of the appropriate aberration correction have been largely overcome so that imaging of living tissues using ISAM and CAO is now possible. Computed imaging in optics is becoming a mature technology poised to make a significant impact in medicine and biology.

Automated interferometric synthetic aperture microscopy and computational adaptive optics for improved optical coherence tomography.

In this paper, we introduce an algorithm framework for the automation of interferometric synthetic aperture microscopy (ISAM). Under this framework, common processing steps such as dispersion correction, Fourier domain resampling, and computational adaptive optics aberration correction are carried out as metrics-assisted parameter search problems. We further present the results of this algorithm applied to phantom and biological tissue samples and compare with manually adjusted results. With the automated algorithm, near-optimal ISAM reconstruction can be achieved without manual adjustment. At the same time, the technical barrier for the nonexpert using ISAM imaging is also significantly lowered.

Noise characterization of broadband fiber Cherenkov radiation as a visible-wavelength source for optical coherence tomography and two-photon fluorescence microscopy.

Optical sources in the visible region immediately adjacent to the near-infrared biological optical window are preferred in imaging techniques such as spectroscopic optical coherence tomography of endogenous absorptive molecules and two-photon fluorescence microscopy of intrinsic fluorophores. However, existing sources based on fiber supercontinuum generation are known to have high relative intensity noise and low spectral coherence, which may degrade imaging performance. Here we compare the optical noise and pulse compressibility of three high-power fiber Cherenkov radiation sources developed recently, and evaluate their potential to replace the existing supercontinuum sources in these imaging techniques.

Stability in computed optical interferometric tomography (part I): stability requirements.

As imaging systems become more advanced and acquire data at faster rates, increasingly dynamic samples can be imaged without concern of motion artifacts. For optical interferometric techniques such as optical coherence tomography, it often follows that initially, only amplitude-based data are utilized due to unstable or unreliable phase measurements. As systems progress, stable phase maps can also be acquired, enabling more advanced, phase-dependent post-processing techniques. Here we report an investigation of the stability requirements for a class of phase-dependent post-processing techniques - numerical defocus and aberration correction with further extensions to techniques such as Doppler, phase-variance, and optical coherence elastography. Mathematical analyses and numerical simulations over a variety of instabilities are supported by experimental investigations.

Stability in computed optical interferometric tomography (Part II): in vivo stability assessment.

Stability is of utmost importance to a wide range of phase-sensitive processing techniques. In Doppler optical coherence tomography and optical coherence elastography, in addition to defocus and aberration correction techniques such as interferometric synthetic aperture microscopy and computational/digital adaptive optics, a precise understanding of the system and sample stability helps to guide the system design and choice of imaging parameters. This article focuses on methods to accurately and quantitatively measure the stability of an imaging configuration in vivo. These methods are capable of partially decoupling axial from transverse motion and are compared against the stability requirements for computed optical interferometric tomography laid out in the first part of this article.

Variations in serum low-density lipoprotein and sST2 among heart failure patients with different ejection fraction groups and their clinical significance.

OBJECTIVE: This study aimed to examine the changes in serum Low Density Lipoprotein Cholesterol (LDL-C) and Soluble Growth Stimulating Expressed Gene 2 Protein (sST2) among Heart Failure (HF) patients with varying ejection fractions and their clinical significance, providing a reference for the clinical assessment of HF severity. METHODS: A total of 238 HF patients treated in our hospital's cardiology department from September 2019 to December 2021 were selected; 68 patients hospitalized in the same period were selected as the control group. General information, LDL-C and echocardiographic results of admitted patients were collected. According to LVEF results and the latest European Society of Cardiology standards in 2021, HF patients were categorized into those with HFpEF (n = 95), HFmrEF (n = 60), and HFrEF (n = 83). Meanwhile, venous blood was collected to determine sST2 and NT-proBNP to compare and analyze the changes and clinical significance of sST2 and LDL-C across the groups. RESULTS: Compared to the control group, the HF group showed significant differences in age, gender, heart rate, smoking history, history of atrial fibrillation, history of diabetes, LVEDD, LVEF, sST2, and NT-proBNP levels (P < .05), but not in LDL-C levels. Significant differences (P < .05) were also found among the 3 HF groups in terms of age, gender, history of atrial fibrillation, LVEDD, LVEF, LDL-C, sST2, and NT-proBNP levels, with an increase in LVEDD, LDL-C, sST2, and NT-proBNP values as the ejection fraction decreased. ROC curve analysis indicated that the area under the curve (AUC) for sST2 in diagnosing HF was 0.915 (P < .05), with an optimal cutoff value of 23.71 ng/mL, a sensitivity of 76.5%, and a specificity of 95.6%; LDL-C was not a significant diagnostic marker for HF (P > .05). Coronary artery disease, NT-proBNP, and sST2 were identified as risk factors for HF. With each unit increase in coronary artery disease, the risk of HF increased by 36.3%; for NT-proBNP, the risk increased by 1.3% per unit; and for sST2, it increased by 18.3% per unit. CONCLUSION: As the ejection fraction decreases in HF patients, serum sST2 and LDL-C values progressively increase, which is clinically significant for predicting the severity of HF. sST2 is an independent risk factor for HF and can enhance the diagnostic accuracy for HF.

Elevations in presepsin, PCT, hs-CRP, and IL-6 levels predict mortality among septic patients in ICU.

BACKGROUND: Aim to investigate the predictive value of changes in presepsin (PSEP), procalcitonin (PCT), high-sensitivity C-reactive protein (hsCRP), and interleukin-6 (IL-6) levels to for mortality in septic patients in intensive care unit (ICU). METHOD: This study enrolled septic patients between November 2020 and December 2021. Levels of PSEP, PCT, hsCRP, and IL-6 were measured on 1st (PSEP_0, PCT_0, hsCRP_0, IL-6_0) and 3rd day (PSEP_3, PCT_3, hsCRP_3, IL-6_3). Follow-up was performed on days 3, 7, 14, 21, and 28 after enrollment. The outcome was all-cause death. RESULTS: The study included 119 participants, and the mortality was 18.5%. In univariable Cox proportional-hazards regression (Cox) analysis, △PSEP (= PSEP_3- PSEP_0) > 211.49 pg/ml (hazard ratio (HR) 2.70, 95% confidence interval (CI) 1.17-6.22), △PCT (= PCT_3- PCT_0) > -0.13 ng/ml (HR 7.31, 95% CI 2.68-19.80), △hsCRP (= hsCRP_3- hsCRP_0) > -19.29 mg/L (HR 6.89, 95% CI 1.61-29.40), and △IL-6 (= IL-6_3- IL-6_0) > 1.00 pg/ml (HR 3.13, 95% CI 1.35-7.24) indicated an increased risk of mortality. The composite concordance index for alterations in all four distinct biomarkers was highest (concordance index 0.83, 95% CI 0.76-0.91), suggesting the optimal performance of this panel in mortality prediction. In decision curve analysis, compared with the APACHE Ⅱ and SOFA scores, the combination of the four biomarkers had a larger net benefit. Interestingly, IL-6 was predominantly produced by monocytes upon LPS stimulation in PBMCs. CONCLUSIONS: △PSEP, △PCT, △hsCRP, and △IL-6 are reliable biomarkers for predicting mortality in septic patients in ICU, and their combination has the best performance.