Host long noncoding RNAs in bacterial infections.

Bacterial infections remain a significant global health concern, necessitating a comprehensive understanding of the intricate host-pathogen interactions that play a critical role in the outcome of infectious diseases. Recent investigations have revealed that noncoding RNAs (ncRNAs) are key regulators of these complex interactions. Among them, long noncoding RNAs (lncRNAs) have gained significant attention because of their diverse regulatory roles in gene expression, cellular processes and the production of cytokines and chemokines in response to bacterial infections. The host utilizes lncRNAs as a defense mechanism to limit microbial pathogen invasion and replication. On the other hand, some host lncRNAs contribute to the establishment and maintenance of bacterial pathogen reservoirs within the host by promoting bacterial pathogen survival, replication, and dissemination. However, our understanding of host lncRNAs in the context of bacterial infections remains limited. This review focuses on the impact of host lncRNAs in shaping host-pathogen interactions, shedding light on their multifaceted functions in both host defense and bacterial survival, and paving the way for future research aimed at harnessing their regulatory potential for clinical applications.

Characterization of Exosomes Released from Mycobacterium abscessus-Infected Macrophages.

Extracellular vesicles (EVs), such as exosomes, play a critical role in cell-to-cell communication and regulating cellular processes in recipient cells. Non-tuberculous mycobacteria (NTM), such as Mycobacterium abscessus, are a group of environmental bacteria that can cause severe lung infections in populations with pre-existing lung conditions, such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). There is limited knowledge of the engagement of EVs in the host-pathogen interactions in the context of NTM infections. In this study, we found that M. abscessus infection increased the release of a subpopulation of exosomes (CD9, CD63, and/or CD81 positive) by mouse macrophages in cell culture. Proteomic analysis of these vesicles demonstrated that M. abscessus infection affects the enrichment of host proteins in exosomes released by macrophages. When compared to exosomes from uninfected macrophages, exosomes released by M. abscessus-infected macrophages significantly improved M. abscessus growth and downregulated the intracellular level of glutamine in recipient macrophages in cell culture. Increasing glutamine concentration in the medium rescued intracellular glutamine levels and M. abscessus killing in recipient macrophages that were treated with exosomes from M. abscessus-infected macrophages. Taken together, our results indicate that exosomes may serve as extracellular glutamine eliminators that interfere with glutamine-dependent M. abscessus killing in recipient macrophages.

ß2-microglobulin induced apoptosis of tumor cells via the ERK signaling pathway by directly interacting with HFE in HER2-overexpressing breast cancer.

BACKGROUND: Our previous study demonstrated that ß2-microglobulin (ß2M) promoted ER+/HER2- breast cancer survival via the SGK1/Bcl-2 signaling pathway. However, the role of ß2M has not been investigated in ER-/HER2+ breast cancer. Here, we aimed to determine the role of ß2M in ER-/HER2+ breast cancer. METHODS: The interaction between ß2M and HFE was confirmed by co-immunoprecipitation, mass spectrometry, yeast two-hybrid screening, and His pull-down. The knockdown and overexpression of ß2M or HFE were performed in MDA-MB-453 cells, and ERK signaling pathway was subsequently analyzed via western blotting. Apoptotic cells were detected using flow cytometer. ß2M, HFE, and p-ERK1/2 were examined in tumor and paired adjacent tissues via immunohistochemistry. RESULTS: HFE was found to be an interacting protein of ß2M in ER-/HER2+ breast cancer cells MDA-MB-453 by co-immunoprecipitation and mass spectrometry. A yeast two-hybrid system and His-pull down experiments verified that ß2M directly interacted with HFE. ß2M and HFE as a complex were mainly located in the cytoplasm, with some on the cytomembrane of MDA-MB-453 cells. In addition to breast cancer cells BT474, endogenous ß2M directly interacted with HFE in breast cancer cells MDA-MB-453, MDA-MB-231, and MCF-7. ß2M activated the ERK signaling pathway by interacting with HFE and induced apoptosis of MDA-MB-453 cells. The expression of HFE and p-ERK1/2 showed significantly high levels in HER2-overexpressing breast cancer tumor tissue compared with adjacent normal tissue, consistent with the results obtained from the cell experiments. CONCLUSIONS: ß2M induced apoptosis of tumor cells via activation of the ERK signal pathway by directly interacting with HFE in HER2-overexpressing breast cancer.

Compact auto-aligning interferometers with picometer precision.

This research introduces a compact, auto-aligning interferometer engineered for measuring translations with a wide angular working range and picometer precision above 1H z. It presents a design ensuring automatic beam alignment during movement through secondary reflection from a corner reflector. The sensor head, a 20×10×10m m 3 all-glass quasi-monolithic structure, exhibits a displacement sensitivity below 1p m/H z 1/2 above 1H z and a wide angular working range of ±200m r a d. This versatile optical design holds promise to improve the sensitivity in applications such as laser ranging, optical seismometers, precision manufacturing, and metrology.

The use of human iPSC-derived alveolar organoids to explore SARS-CoV-2 variant infections and host responses.

Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) primarily targets the respiratory system. Physiologically relevant human lung models are indispensable to investigate virus-induced host response and disease pathogenesis. In this study, we generated human induced pluripotent stem cell (iPSC)-derived alveolar organoids (AOs) using an established protocol that recapitulates the sequential steps of in vivo lung development. AOs express alveolar epithelial type II cell protein markers including pro-surfactant protein C and ATP binding cassette subfamily A member 3. Compared to primary human alveolar type II cells, AOs expressed higher mRNA levels of SARS-CoV-2 entry factors, angiotensin-converting enzyme 2 (ACE2), asialoglycoprotein receptor 1 (ASGR1) and basigin (CD147). Considering the localization of ACE2 on the apical side in AOs, we used three AO models, apical-in, sheared and apical-out for SARS-CoV-2 infection. All three models of AOs were robustly infected with the SARS-CoV-2 irrespective of ACE2 accessibility. Antibody blocking experiment revealed that ASGR1 was the main receptor for SARS-CoV2 entry from the basolateral in apical-in AOs. AOs supported the replication of SARS-CoV-2 variants WA1, Alpha, Beta, Delta, and Zeta and Omicron to a variable degree with WA1 being the highest and Omicron being the least. Transcriptomic profiling of infected AOs revealed the induction of inflammatory and interferon-related pathways with NF-κB signaling being the predominant host response. In summary, iPSC-derived AOs can serve as excellent human lung models to investigate infection of SARS-CoV-2 variants and host responses from both apical and basolateral sides.

Mycobacterium abscessus extracellular vesicles increase mycobacterial resistance to clarithromycin in vitro.

Nontuberculous Mycobacteria (NTM) are a group of emerging bacterial pathogens that have been identified in cystic fibrosis (CF) patients with microbial lung infections. The treatment of NTM infection in CF patients is challenging due to the natural resistance of NTM species to many antibiotics. Mycobacterium abscessus is one of the most common NTM species found in the airways of CF patients. In this study, we characterized the extracellular vesicles (EVs) released by drug-sensitive M. abscessus untreated or treated with clarithromycin (CLR), one of the frontline anti-NTM drugs. Our data show that exposure to CLR increases mycobacterial protein trafficking into EVs as well as the secretion of EVs in culture. Additionally, EVs released by CLR-treated M. abscessus increase M. abscessus resistance to CLR when compared to EVs from untreated M. abscessus. Proteomic analysis further indicates that EVs released by CLR-treated M. abscessus carry an increased level of 50S ribosomal subunits, the target of CLR. Taken together, our results suggest that EVs play an important role in M. abscessus resistance to CLR treatment.

High-precision laser beam lateral displacement measurement based on differential wavefront sensing.

Accurately lateral displacement measurement is essential for a vast of non-contact sensing technologies. Here, we introduce a high-precision lateral displacement measurement method based on differential wavefront sensing (DWS). Compared to the conventional differential power sensing (DPS) method, the DWS method based on phase readout has the potential to achieve a higher resolution. The beam lateral displacement can be obtained by the curvature distribution of the wavefront on the surface of the detector. According to the theoretical model of the DWS method, the sensitivity of the lateral displacement can be greatly improved by increasing the wavefront curvature of the measured laser beam by means of lenses. An optical system for measuring the lateral displacement of the laser beam is built and calibrated by a high-precision hexapod. The experimental results show that the DWS-based lateral displacement measurement achieves a resolution of 40 pm/Hz1/2 (at 1-10 Hz) with a linear range of about 40 µm, which is consistent with the theoretical model. This technique can be applied to high-precision multi-degree-of-freedom interferometers.

Time- and temperature-dependent postmortem ∆9-tetrahydrocannabinol concentration changes in rabbits following controlled inhaled cannabis administration.

ostmortem redistribution (PMR), a well-known phenomenon in forensic toxicology, can result in substantial changes in drug concentrations after death, depending on the chemical characteristics of the drug, blood collection site, storage conditions of the body and postmortem interval (PMI). Limited PMR data are available for ∆9-tetrahydrocannabinol (THC), the primary psychoactive component in Cannabis sativa. PMR was evaluated after controlled cannabis inhalation via a smoking machine and exposure chamber in New Zealand white rabbits. Necropsies were performed on five control rabbits immediately after euthanasia, whereas 27 others were stored at room temperature (21°C) or refrigerated conditions (4°C) until necropsy at 2, 6, 16, 24 or 36 h after death. THC and its Phase I and glucuronidated Phase II metabolites were quantified in blood, vitreous humor, urine, bile and tissues by liquid chromatography-tandem mass spectrometry (LC-MS-MS). Under refrigerated temperature, heart blood THC concentrations significantly increased at PMI 2 h in rabbits, whereas peripheral blood THC concentrations showed a significant increase at PMI 16 h. Central:peripheral blood and liver:peripheral blood ratios for THC ranged from 0.13 to 4.1 and 0.28 to 8.9, respectively. Lung revealed the highest THC concentrations, while brain and liver exhibited the most stable THC concentrations over time. This report contributes much needed data to our understanding of postmortem THC behavior and can aid toxicologists in the interpretation of THC concentrations in medicolegal death investigations.

MicroRNA-9-1 Attenuates Influenza A Virus Replication via Targeting Tankyrase 1.

An unstable influenza genome leads to the virus resistance to antiviral drugs that target viral proteins. Thus, identification of host factors essential for virus replication may pave the way to develop novel antiviral therapies. In this study, we investigated the roles of the poly(ADP-ribose) polymerase enzyme, tankyrase 1 (TNKS1), and the endogenous small noncoding RNA, miR-9-1, in influenza A virus (IAV) infection. Increased expression of TNKS1 was observed in IAV-infected human lung epithelial cells and mouse lungs. TNKS1 knockdown by RNA interference repressed influenza viral replication. A screen using TNKS1 3'-untranslation region (3'-UTR) reporter assays and predicted microRNAs identified that miR-9-1 targeted TNKS1. Overexpression of miR-9-1 reduced influenza viral replication in lung epithelial cells as measured by viral mRNA and protein levels as well as virus production. miR-9-1 induced type I interferon production and enhanced the phosphorylation of STAT1 in cell culture. The ectopic expression of miR-9-1 in the lungs of mice by using an adenoviral viral vector enhanced type I interferon response, inhibited viral replication, and reduced susceptibility to IAV infection. Our results indicate that miR-9-1 is an anti-influenza microRNA that targets TNKS1 and enhances cellular antiviral state.

SNHG15 aids SARS-CoV-2 entry via RABL2A.

Angiotensin-converting enzyme 2 (ACE2) and several proteins have been identified as entry factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, whether long noncoding RNAs are involved in SARS-CoV-2 entry remains unknown. In this study, we investigated the role of small nucleolar RNA host gene 15 (SNHG15) in SARS-CoV-2 entry using a SARS-CoV-2 spike pseudotyped lentivirus with a luciferase reporter. Overexpression of SNHG15 promoted but SNHG15 knockdown limited SARS-CoV-2 entry in a dose- and time-dependent manner. SNHG15 interacted with Rab-like protein 2A (RABL2A). Overexpression and knockdown of RABL2A produced similar effects on SARS-CoV-2 entry as those of SNHG15. Furthermore, RABL2A knockdown abolished the SNHG15-mediated increase in SARS-CoV-2 entry. In conclusion, SNHG15 is a critical regulatory factor that aids SARS-CoV-2 entry through RABL2A.

Cellular microRNAs target SARS-CoV-2 spike protein and restrict viral replication.

MicroRNAs (miRNAs) regulate gene expression posttranscriptionally and are implicated in viral replication and host tropism. miRNAs can impact the viruses either by directly interacting with the viral genome or modulating host factors. Although many miRNAs have predicted binding sites in the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) viral RNA genome, little experimental validation has been done. We first identified 492 miRNAs that have binding site(s) on the spike (S) viral RNA by a bioinformatics prediction. We then validated the selected 39 miRNAs by examining S-protein levels after coexpressing the S-protein and a miRNA into the cells. Seven miRNAs were found to reduce the S-protein levels by more than 50%. Among them, miR-15a, miR-153, miR-298, miR-508, miR-1909, and miR-3130 also significantly reduced SARS-CoV-2 viral replication. SARS-CoV-2 infection decreased the expression levels of miR-298, miR-497, miR-508, miR-1909, and miR-3130, but had no significant effects on miR-15a and miR-153 levels. Intriguingly, the targeting sequences of these miRNAs on the S viral RNA showed sequence conservation among the variants of concern. Our results suggest that these miRNAs elicit effective antiviral defense against SARS-CoV-2 by modulating S-protein expression and are likely targeting all the variants. Thus, the data signify the therapeutic potential of miRNA-based therapy for SARS-CoV-2 infections.NEW & NOTEWORTHY MicroRNAs can impact viruses either by directly interacting with the virus genome or by modulating host factors. We identified that cellular miRNAs regulate effective antiviral defense against SARS-CoV-2 via modulating spike protein expression, which may offer a potential candidate for antiviral therapy.

Axin1: A novel scaffold protein joins the antiviral network of interferon.

Acute respiratory infection by influenza virus is a persistent and pervasive public health problem. Antiviral innate immunity initiated by type I interferon (IFN) is the first responder to pathogen invasion and provides the first line of defense. We discovered that Axin1, a scaffold protein, was reduced during influenza virus infection. We also found that overexpression of Axin1 and the chemical stabilizer of Axin1, XAV939, reduced influenza virus replication in lung epithelial cells. This effect was also observed with respiratory syncytial virus and vesicular stomatitis virus. Axin1 boosted type I IFN response to influenza virus infection and activated JNK/c-Jun and Smad3 signaling. XAV939 protected mice from influenza virus infection. Thus, our studies provide new mechanistic insights into the regulation of the type I IFN response and present a new potential therapeutic of targeting Axin1 against influenza virus infection.

Weak-Light Phase-Locking Time Delay Interferometry with Optical Frequency Combs.

In the future space-borne gravitational wave (GW) detector, the optical transponder scheme, i.e., the phase-locking scheme, will be utilized so as to maintain the signal-to-noise ratio (SNR). In this case, the whole constellation will share one common laser equivalently, which enables the considerable simplification of time delay interferometry (TDI) combinations. Recently, and remarkably, the unique combination of TDI and optical frequency comb (OFC) has shown a bright prospect for the future space-borne missions. When the laser frequency noise and the clock noise are synchronized using OFC as the bridge, the data streams will be reasonably simplified. However, in the optical transponder scheme, the weak-light phase-locking (WLPL) loops could bring additional noises. In this work, we analyze the phase-locking scheme with OFC and transfer characteristics of the noises including the WLPL noise. We show that the WLPL noise can be efficiently reduced by using the specific TDI combination, and the cooperation of phase-locking and frequency combs can greatly simplify the post-processing.

Designing incentive mechanism in contract farming considering reciprocity preference.

Contract farming is a growing practice in agricultural economy. A well-designed crop-planting and buyout contract, offered by an enterprise, to a fraction of contract farmers brings benefit to farmers as well as to the enterprise itself. However, in the process of contract fulfillment, farmers possess private information about the degree of effort on fulfilling the contract of themselves. Thus, the more informed farmers may not work hard in the process of planting crops. This opportunistic behavior of farmers caused by asymmetric information has seriously affected the sustainability of contract farming. An enterprise with reciprocity preference tends to make a contract both improves farmers' welfare and brings enough profit to sustain its own operations, while a farmer with reciprocity will work hard in return for the enterprise's reward. In this paper, we develop a non-profit index principal-agent model between enterprises and farmers, assuming both have reciprocity preference, to investigate how to design an incentive mechanism in contract farming. We begin our analysis by establishing a non-profit index evaluation system to evaluate farmers' effort degree in contract fulfillment. Then we solve principal-agent problem with the assumption that farmers' expected certainty income premium (ECIP) is constant. We find that in the perfect Bayesian equilibrium, farmers with higher degree of reciprocity preference require less ECIP, and will improve efforts to complete contract tasks, even actively sacrifice their own interests to repay extra rewards from enterprises. Furthermore, we explore our model to the scenario in which farmers' ECIP is a function of enterprise payment difference (EPD). We find that the higher the degree of reciprocity preference of farmers, the greater the probability of enterprises to increase income. Numerical simulations are conducted to verify the validity of the conclusions. Our study shows that the reciprocity preference behavior of enterprises and farmers improves the fulfillment rate of contract farming, which contributes to the realization of the incentive mechanism of contract farming.

Regulation of influenza A virus infection by Lnc-PINK1-2:5.

Influenza virus causes approximately 291,000 to 646,000 human deaths worldwide annually. It is also a disease of zoonotic importance, affecting animals such as pigs, horses, and birds. Even though vaccination is being used to prevent influenza virus infection, there are limited options available to treat the disease. Long noncoding RNAs (lncRNAs) are RNA molecules with more than 200 nucleotides that do not translate into proteins. They play important roles in the physiological and pathological processes. In this study, we identified a novel transcript, Lnc-PINK1-2:5 that was upregulated by influenza virus. This lncRNA was predominantly located in the nucleus and was not affected by type I interferons. Overexpression of Lnc-PINK1-2:5 reduced the influenza viral mRNA and protein levels in cells as well as titres in culture media. Knockdown of Lnc-PINK1-2:5 using CRISPR interference enhanced the virus replication. Antiviral activity of Lnc-PINK1-2:5 was independent of influenza virus strains. RNA sequencing analysis revealed that Lnc-PINK1-2:5 upregulated thioredoxin interacting protein (TXNIP) during influenza virus infection. Overexpression of TXNIP reduced influenza virus infection, suggesting that TXNIP is an antiviral gene. Knockdown of TXNIP abolished the Lnc-PINK1-2:5-mediated increase in influenza virus infection. In conclusion, the newly identified Lnc-PINK1-2:5 isoform is an anti-influenza lncRNA acting through the upregulation of TXNIP gene expression.

All-fiber heterodyne velocity and displacement interferometer based on DPLL Doppler tracking with sub-nanometer per second and picometer sensitivity.

Velocity and displacement measurements play an important role not only in the process of industrial production and metrology on the ground but also in satellite gravity measurement in space. A high-precision all-fiber heterodyne velocity and displacement interferometer based on digital phase-locked loop (DPLL) Doppler tracking is proposed in this paper. The target velocity is measured by tracking the heterodyne frequency changes of the beat-note signal, and the displacement is obtained by the integrated phase of the Doppler frequency change. A dual-signal differential optical-path scheme combined with DPLL signal tracking technology enables high-precision and high-linearity measurement of velocity and displacement simultaneously. For integration and compactness, the interferometer uses all-fiber optics that are packaged in a small box with dimensions of 150×150×70m m 3, except for an externally fiber-connected collimator as the sensor head. The experimental results show a velocity sensitivity below 30p m/s/H z 1/2 in the 0.03-2 Hz band and a displacement sensitivity below 10p m/H z 1/2 above 0.4 Hz.

Long Noncoding RNA FENDRR Inhibits Lung Fibroblast Proliferation via a Reduction of ß-Catenin.

Idiopathic Pulmonary Fibrosis (IPF) is a chronic, progressive, and usually lethal lung disease and it has been widely accepted that fibroblast proliferation is one of the key characteristics of IPF. Long noncoding RNAs (lncRNAs) play vital roles in the pathogenesis of many diseases. In this study, we investigated the role of lncRNA FENDRR on fibroblast proliferation. Human lung fibroblasts stably overexpressing FENDRR showed a reduced cell proliferation compared to those expressing the control vector. On the other hand, FENDRR silencing increased fibroblast proliferation. FENDRR bound serine-arginine rich splicing factor 9 (SRSF9) and inhibited the phosphorylation of p70 ribosomal S6 kinase 1 (PS6K), a downstream protein of the mammalian target of rapamycin (mTOR) signaling. Silencing SRSF9 reduced fibroblast proliferation. FENDRR reduced ß-catenin protein, but not mRNA levels. The reduction of ß-catenin protein levels in lung fibroblasts by gene silencing or chemical inhibitor decreased fibroblast proliferation. Adenovirus-mediated FENDRR transfer to the lungs of mice reduced asbestos-induced fibrotic lesions and collagen deposition. RNA sequencing of lung tissues identified 7 cell proliferation-related genes that were up-regulated by asbestos but reversed by FENDRR. In conclusion, FENDRR inhibits fibroblast proliferation and functions as an anti-fibrotic lncRNA.

Shot-noise-limit performance of a weak-light phase readout system for intersatellite heterodyne interferometry.

A laser interferometer will be used in the spaceborne gravitational-wave detection missions to measure the inter-satellite optical pathlength variations. The phase readout system of the interferometer needs to be carefully designed and tested to accomplish a shot-noise-limited detection performance under the situation of pico-Watt level received lights. In this work, a scheme based on dual-tone acousto-optic diffraction is presented to verify the performance of the weak-light phase readout system. By optimizing the parameters of the photoreceiver and the local strong-light power, the signal-to-noise ratio of the beat-note signal is enhanced. Thanks to the scheme's common-mode noise rejections for the laser frequency noise, and the optical-path noise, etc., the differential phase noise has achieved a performance of 2×10-4 rad/Hz1/2, which is dominated by the weak-light (∼13 pW) shot noise above the frequencies of 2 mHz.

Experimental scheme and noise analysis of weak-light phase locked loop for large-scale intersatellite laser interferometer.

In the current space gravitational wave (GW) detection, satellites are separated by millions of kilometers. As a result, watts of laser from one satellite is attenuated to the picowatt level at the other end due to the Gaussian beam divergence and the finite aperture of the telescope. Establishing an effective interferometry with such weak-light is a major challenge. The key is to enhance the weak-light while preserving its phase information, which carries the actual GW signal. This can be accomplished by employing an optical phase-locked loop (PLL) to lock the phase of a local oscillator (LO) laser to the weak-light and then sending the power-amplified LO back to the interferometer on the other satellite. Although shot-noise-limited performance of the picowatt level weak-light PLL has been achieved for high frequencies, it remains elusive for frequencies below 0.1 Hz. Here, we propose a three-step experimental scheme to identify the main noise sources of the weak-light PLL, which turn out to be the low-frequency phase measurement noise, the weak-light shot noise, and the laser phase noise. In this paper, the first step experiment result shows that the out-loop phase noise can be suppressed to a level less than 6 × 10-6 rad/√Hz from 6 mHz to 1 Hz by first using the special pilot-tone technique in the PLL to directly reduce the sampling time jitter noise in the digital phasemeter. The out-loop phase noise is mainly limited by the signal amplitude variation and differential time jitter noise of the reference clock.

miR-29a is a negative regulator of influenza virus infection through targeting of the frizzled 5 receptor.

Influenza A virus (IAV) infections result in a large number of deaths and substantial economic losses each year. MicroRNAs repress gene expression and are involved in virus-host interactions. miR-29a is known to have anti-tumor and anti-fibrotic effects. However, the role of miR-29a in IAV infection is unclear. In the present study, we investigated the effect of miR-29a on IAV infection and the mechanisms by which it functions. IAV infection was found to cause decreased miR-29a expression in lung epithelial A549 cells and mouse lungs. Overexpression of miR-29a reduced IAV mRNA and protein levels and progeny virus production in HEK293 and A549 cells. Inhibition of IAV infection by miR-29a was observed with different strains of IAV, including A/PR/8/34, A/WSN/1933, and clinical isolates A/OK/3052/09 and A/OK/309/06 H3N2. Knockout of miR-29a using CRISPR/Cas9 resulted in an increase in viral mRNA and protein levels, confirming that miR-29a suppresses IAV infection. A 3' untranslated region (3'-UTR) reporter assay showed that miR-29a had binding sites in the 3'-UTR of the Wnt-Ca2+ signaling receptor frizzled 5 gene, and overexpression of miR-29a reduced the level of the endogenous frizzled 5 protein. Wnt5a treatment of HEK293 and A549 cells enhanced IAV infection. Our results suggest that miR-29a inhibits IAV infection, probably via the frizzled 5 receptor.