Carnosic acid nanocluster-based framework combined with PD-1 inhibitors impeded tumorigenesis and enhanced immunotherapy in hepatocellular carcinoma.

Clinically, the immune checkpoint inhibitor anti-PD-1 antibody has shown a certain effect in the treatment of hepatocellular carcinoma (HCC), which is limited to a small number of patients with HCC. This study aims to reveal whether carnosic acid nanocluster-based framework (CA-NBF) has a sensitization effect on anti-PD-1 antibody in the treatment of HCC at the cellular and animal levels. MHCC97H cells were treated with CA-NBF, anti-PD-1 and their combination. The effects of CA-NBF and anti-PD-1 on cell proliferation, cell cycle, apoptosis, invasion, and migration were evaluated by MTT assay, flow cytometry, and scratch test. The effects of CA-NBF and anti-PD-1 on Wnt/ß-catenin signaling pathway in MHCC97H cells were detected. A BALB/C nude mouse model of hepatocellular carcinoma was established, and the tumor growth was observed at different time points. The expression of cytotoxic T lymphocyte and helper T lymphocyte markers CD8 and CD4 in tumor tissues was detected by immunohistochemistry. Western blotting was used to detect the Wnt/ß-catenin signaling pathway proteins (Wnt-3a, ß-catenin, and GSK-3ß) level in tumor tissues after CA-NBF and anti-PD-1 treatment. CA-NBF activity was significantly higher than CA, which could prominently reduce the proliferation, migration and invasion of MHCC97H cells and enhance apoptosis by inactivating Wnt/ß-catenin signaling pathway. CA-NBF combined with anti-PD-1 antibody further enhanced cell proliferation, migration, invasion and pro-apoptosis but had no significant effect on Wnt/ß-catenin signaling pathway. CA-NBF in vivo improved the tumor response to PD1 immune checkpoint blockade in HCC, manifested by reducing tumor size and weight, promoting CD4 and CD8 expression. CA-NBF combined with anti-PD-1 have stronger immunomodulatory and anticancer effects without increasing biological toxicity.

Acoustofluidic manipulation for submicron to nanoparticles.

Particles, ranging from submicron to nanometer scale, can be broadly categorized into biological and non-biological types. Submicron-to-nanoscale bioparticles include various bacteria, viruses, liposomes, and exosomes. Non-biological particles cover various inorganic, metallic, and carbon-based particles. The effective manipulation of these submicron to nanoparticles, including their separation, sorting, enrichment, assembly, trapping, and transport, is a fundamental requirement for different applications. Acoustofluidics, owing to their distinct advantages, have emerged as a potent tool for nanoparticle manipulation over the past decade. Although recent literature reviews have encapsulated the evolution of acoustofluidic technology, there is a paucity of reports specifically addressing the acoustical manipulation of submicron to nanoparticles. This article endeavors to provide a comprehensive study of this topic, delving into the principles, apparatus, and merits of acoustofluidic manipulation of submicron to nanoparticles, and discussing the state-of-the-art developments in this technology. The discourse commences with an introduction to the fundamental theory of acoustofluidic control and the forces involved in nanoparticle manipulation. Subsequently, the working mechanism of acoustofluidic manipulation of submicron to nanoparticles is dissected into two parts, dominated by the acoustic wave field and the acoustic streaming field. A critical analysis of the advantages and limitations of different acoustofluidic platforms in nanoparticles control is presented. The article concludes with a summary of the challenges acoustofluidics face in the realm of nanoparticle manipulation and analysis, and a forecast of future development prospects.

Heterogeneous Photocatalytic C(sp2)‒H Activation of Formate for Hydrocarboxylation of Alkenes.

Light-driven carboxylation offers a promising approach for synthesizing valuable fine chemicals under mild conditions. Here we disclose a heterogeneous photocatalytic strategy of C(sp2)‒H activation of formate for hydrocarboxylation of alkenes over zinc indium sulfide (ZnIn2S4) under visible light. This protocol functions well with a variety of substituted styrenes with good to excellent yields; it also works for unactivated alkenes albeit with lower yields. Mechanistic studies confirm the existence of CO2•- as a key intermediate. It was found that C(sp2)‒H activation of formate is induced by S• species on the surface of ZnIn2S4 via hydrogen atom transfer (HAT) instead of a photogenerated hole oxidation mechanism. Moreover, both cleavage of the C(sp2)‒H of HCOO- and formation of a benzylic anion were found to be involved in the rate-determining step for the hydrocarboxylation of styrene.

Noncanonical amino acid mutagenesis in response to recoding signal-enhanced quadruplet codons.

While amber suppression is the most common approach to introduce noncanonical amino acids into proteins in live cells, quadruplet codon decoding has potential to enable a greatly expanded genetic code with up to 256 new codons for protein biosynthesis. Since triplet codons are the predominant form of genetic code in nature, quadruplet codon decoding often displays limited efficiency. In this work, we exploited a new approach to significantly improve quadruplet UAGN and AGGN (N = A, U, G, C) codon decoding efficiency by using recoding signals imbedded in mRNA. With representative recoding signals, the expression level of mutant proteins containing UAGN and AGGN codons reached 48% and 98% of that of the wild-type protein, respectively. Furthermore, this strategy mitigates a common concern of reading-through endogenous stop codons with amber suppression-based system. Since synthetic recoding signals are rarely found near the endogenous UAGN and AGGN sequences, a low level of undesirable suppression is expected. Our strategy will greatly enhance the utility of noncanonical amino acid mutagenesis in live-cell studies.

Improving anammox activity and reactor start-up speed by using CO2/NaHCO3 buffer.

Anammox bacteria grow slowly and can be affected by large pH fluctuations. Using suitable buffers could make the start-up of anammox reactors easy and rapid. In this study, the effects of three kinds of buffers on the nitrogen removal and growth characteristics of anammox sludge were investigated. Reactors with CO2/NaHCO3 buffer solution (CCBS) performed the best in nitrogen removal, while 4-(2-hydroxyerhyl)piperazine-1-ethanesulfonic acid (HEPES) and phosphate buffer solution (PBS) inhibited the anammox activity. Reactors with 50 mmol/L CCBS could start up in 20 days, showing the specific anammox activity and anammox activity of 1.01±0.10 gN/(gVSS·day) and 0.83±0.06 kgN/(m3·day), respectively. Candidatus Kuenenia was the dominant anammox bacteria, with a relative abundance of 71.8%. Notably, anammox reactors could also start quickly by using 50 mmol/L CCBS under non-strict anaerobic conditions. These findings are meaningful for the quick start-up of engineered anammox reactors and prompt enrichment of anammox bacteria.

Unlocking the NIR-II AIEgen for High Brightness through Intramolecular Electrostatic Locking.

Fluorescent imaging and biosensing in the near-infrared-II (NIR-II) window holds great promise for non-invasive, radiation-free, and rapid-response clinical diagnosis. However, it's still challenging to develop bright NIR-II fluorophores. In this study, we report a new strategy to enhance the brightness of NIR-II aggregation-induced emission (AIE) fluorophores through intramolecular electrostatic locking. By introducing sulfur atoms into the side chains of the thiophene bridge in TSEH molecule, the molecular motion of the conjugated backbone can be locked through intramolecular interactions between the sulfur and nitrogen atoms. This leads to enhanced NIR-II fluorescent emission of TSEH in both solution and aggregation states. Notably, the encapsulated nanoparticles (NPs) of TSEH show enhanced brightness, which is 2.6-fold higher than TEH NPs with alkyl side chains. The in vivo experiments reveal the feasibility of TSEH NPs in vascular and tumor imaging with a high signal-to-background ratio and precise resection for tiny tumors. In addition, polystyrene nanospheres encapsulated with TSEH are utilized for antigen detection in lateral flow assays, showing a signal-to-noise ratio 1.9-fold higher than the TEH counterpart in detecting low-concentration antigens. This work highlights the potential for developing bright NIR-II fluorophores through intramolecular electrostatic locking and their potential applications in clinical diagnosis and biomedical research.

Impact of the COVID-19 pandemic on liver disease-related mortality rates in the United States.

BACKGROUND & AIMS: The pandemic has resulted in an increase of deaths not directly related to COVID-19 infection. We aimed to use a national death dataset to determine the impact of the pandemic on people with liver disease in the USA, focusing on alcohol-associated liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). METHODS: Using data from the National Vital Statistic System from the Center for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) platform and ICD-10 codes, we identified deaths associated with liver disease. We evaluated observed vs. predicted mortality for 2020-2021 based on trends from 2010-2019 with joinpoint and prediction modelling analysis. RESULTS: Among 626,090 chronic liver disease-related deaths between 2010 and 2021, Age-standardised mortality rates (ASMRs) for ALD dramatically increased between 2010-2019 and 2020-2021 (annual percentage change [APC] 3.5% to 17.6%, p <0.01), leading to a higher observed ASMR (per 100,000 persons) than predicted for 2020 (15.67 vs. 13.04) and 2021 (17.42 vs. 13.41). ASMR for NAFLD also increased during the pandemic (APC: 14.5%), whereas the rates for hepatitis B and C decreased. Notably, the ASMR rise for ALD was most pronounced in non-Hispanic Whites, Blacks, and Alaska Indians/Native Americans (APC: 11.7%, 10.8%, 18.0%, all p <0.05), with similar but less critical findings for NAFLD, whereas rates were steady for non-Hispanic Asians throughout 2010-2021 (APC: 4.9%). The ASMR rise for ALD was particularly severe for the 25-44 age group (APC: 34.6%, vs. 13.7% and 12.6% for 45-64 and ≥65, all p <0.01), which were also all higher than pre-COVID-19 rates (all p <0.01). CONCLUSIONS: ASMRs for ALD and NAFLD increased at an alarming rate during the COVID-19 pandemic with the largest disparities among the young, non-Hispanic White, and Alaska Indian/Native American populations. IMPACT AND IMPLICATIONS: The pandemic has led to an increase of deaths directly and indirectly related to SARS-CoV-2 infection. As shown in this study, age-standardised mortality rates for alcohol-associated liver disease and non-alcoholic fatty liver disease substantially increased during the COVID-19 pandemic in the USA and far exceeded expected levels predicted from past trends, especially among the young, non-Hispanic White, and Alaska Indian/Native American populations. However, much of this increase was not directly related to COVID-19. Therefore, for the ongoing pandemic as well as its recovery phase, adherence to regular monitoring and care for people with chronic liver disease should be prioritised and awareness should be raised among patients, care providers, healthcare systems, and public health policy makers.

Effectiveness and tolerability of camrelizumab combined with molecular targeted therapy for patients with unresectable or advanced HCC.

There is a lack of effective programmed cell death protein 1 (PD-1)-targeted immunotherapy with good tolerability in patients with advanced hepatocellular carcinoma (HCC) and severely compromised liver function. We assessed patient outcomes after combined camrelizumab and molecular targeted therapy in a multicenter cohort study in China. The study included 99 patients with advanced HCC (58 Child-Pugh A and 41 Child-Pugh B), 84 of them received camrelizumab combined with molecular targeted therapy from January 10, 2019, to March 31, 2021. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and adverse events (AEs) were assessed. The median follow-up was 12.1 months. For patients with Child-Pugh B, the OS probability at 12-months, ORR and DCR were 49.7%, 31.7% and 65.9%, respectively, and the median PFS was 5.1 months [95% confidence interval (CI) 3.0-7.1], which were comparable with Child-Pugh A patients, although median OS was shorter in Child-Pugh B patients (20.5 vs.13.4 months, P = 0.12). In multivariate analysis, macrovascular infiltration (MVI), but not sex, age, hepatitis B virus etiology, extrahepatic metastasis, Child-Pugh B, or AFP > 400 ng/ml, was associated with 12-months OS [hazard ratio (HR) 2.970, 95% CI 1.276-6.917, P = 0.012] and ORR (HR 2.906, 95% CI 1.18-7.16, P = 0.020). Grade 3/4 immune-related AEs occurred in 26.8% of Child-Pugh B patients, including one potentially treatment-related death. In both groups, the most common AEs were immune thrombocytopenia and hepatotoxicity. Camrelizumab combined with targeted therapy showed favorable effectiveness and tolerability with manageable toxicities in Chinese HCC patients, regardless of Child-Pugh A/B liver function. MVI was associated with suboptimal immunotherapy response and poor prognosis.

Racial and Ethnic Disparities in Years of Potential Life Loss Among Patients With Cirrhosis During the COVID-19 Pandemic in the United States.

INTRODUCTION: Our aim was to evaluate the impact of race/ethnicity on cirrhosis-related premature death during the COVID-19 pandemic. METHODS: We obtained cirrhosis-related death data (n = 872,965, January 1, 2012-December 31, 2021) from the US National Vital Statistic System to calculate age-standardized mortality rates and years of potential life lost (YPLL) for premature death aged 25-64 years. RESULTS: Significant racial/ethnic disparity in cirrhosis-related age-standardized mortality rates was noted prepandemic but widened during the pandemic, with the highest excess YPLL for the non-Hispanic American Indian/American Native (2020: 41.0%; 2021: 68.8%) followed by other minority groups (28.7%-45.1%), and the non-Hispanic White the lowest (2020: 20.7%; 2021: 31.6%). COVID-19 constituted >30% of the excess YPLLs for Hispanic and non-Hispanic American Indian/American Native in 2020, compared with 11.1% for non-Hispanic White. DISCUSSION: Ethnic minorities with cirrhosis experienced a disproportionate excess death and YPLLs in 2020-2021.

HIV-related mortality in the United States during the COVID-19 pandemic: A population-based study.

BACKGROUND: US progress toward ending the HIV epidemic was disrupted during the COVID-19 pandemic. OBJECTIVES: To determine the impact of the pandemic on HIV-related mortality and potential disparities. METHODS: Using data from the Centers for Disease Control and Prevention and the United States (US) Census Bureau, HIV-related mortality data of decedents aged ≥25 years between 2012 and 2021 were analyzed. Excess HIV-related mortality rates were estimated by determining the difference between observed and projected mortality rates during the pandemic. The trends of mortality were quantified with joinpoint regression analysis. RESULTS: Of the 79,725 deaths documented in adults aged 25 years and older between 2012 and 2021, a significant downward trend was noted in HIV-related mortality rates before the pandemic, followed by a surge during the pandemic. The observed mortality rates were 18.8% (95% confidence interval [CI]: 13.1%-25.5%) and 25.4% (95%CI: 19.9%-30.4%) higher than the projected values in 2020 and 2021, respectively. Both of these percentages were higher than that in the general population in 2020 (16.4%, 95%CI: 14.9%-17.9%) and 2021 (19.8%, 95%CI: 18.0%-21.6%), respectively. Increased HIV-related mortality was observed across all age subgroups, but those aged 25-44 years demonstrated the greatest relative increase and the lowest COVID-19-related deaths when compared to middle- and old-aged decedents. Disparities were observed across racial/ethnic subgroups and geographic regions. CONCLUSIONS: The pandemic led to a reversal in the attainments made to reduce the prevalence of HIV. Individuals living with HIV were disproportionately affected during the pandemic. Thoughtful policies are needed to address the disparity in excess HIV-related mortality.

Excess risk for acute myocardial infarction mortality during the COVID-19 pandemic.

The COVID-19 pandemic has had a detrimental impact on the healthcare system. Our study armed to assess the extent and the disparity in excess acute myocardial infarction (AMI)-associated mortality during the pandemic, through the recent Omicron outbreak. Using data from the CDC's National Vital Statistics System, we identified 1 522 669 AMI-associated deaths occurring between 4/1/2012 and 3/31/2022. Accounting for seasonality, we compared age-standardized mortality rate (ASMR) for AMI-associated deaths between prepandemic and pandemic periods, including observed versus predicted ASMR, and examined temporal trends by demographic groups and region. Before the pandemic, AMI-associated mortality rates decreased across all subgroups. These trends reversed during the pandemic, with significant rises seen for the youngest-aged females and males even through the most recent period of the Omicron surge (10/2021-3/2022). The SAPC in the youngest and middle-age group in AMI-associated mortality increased by 5.3% (95% confidence interval [CI]: 1.6%-9.1%) and 3.4% (95% CI: 0.1%-6.8%), respectively. The excess death, defined as the difference between the observed and the predicted mortality rates, was most pronounced for the youngest (25-44 years) aged decedents, ranging from 23% to 34% for the youngest compared to 13%-18% for the oldest age groups. The trend of mortality suggests that age and sex disparities have persisted even through the recent Omicron surge, with excess AMI-associated mortality being most pronounced in younger-aged adults.

Amphiphilic HZSM-5 for Cyclopentene Hydration at the Liquid-Liquid Interface in Pickering Emulsion.

Zeolite is considered an ideal catalyst for olefin hydration due to its high specific surface area and abundant acid sites. However, the immiscibility of the water-oil two phases in olefin hydration limits mass transfer, and the side reaction of etherification occurs acutely, resulting in a low yield of alcohol. Thus, water-oil amphiphilic HZSM-5 was prepared by sulfonating silanized zeolite. The successful introduction of organic and sulfonic acid groups is demonstrated by FT-IR, TG, and water contact angles. Amphiphilic HZSM-5 can stabilize the Pickering emulsion and catalyze cyclopentene hydration at the phase interface. In addition, NH3-TPD and Py-IR show that the amount of strong BroÌ·nsted acid sites of zeolites increases significantly after sulfonation. This facilitates the rate-determining step of cyclopentene activation by H+ to form carbocation. Moreover, the nucleophilic side reactions are inhibited by a high concentration of H+. Finally, under the optimized reaction condition, the conversion of cyclopentene can achieve 5.066% with a selectivity of 85.37% to cyclopentanol, which almost reaches the reaction equilibrium.

Excess psoriasis and psoriatic arthritis mortality during the COVID-19 pandemic in the United States: A nationwide population-based study from 2010 to 2021.

BACKGROUND: Little is known about mortality trends among patients with psoriasis (PsO) and psoriatic arthritis (PsA) in the United States. OBJECTIVES: To ascertain mortality trends of PsO and PsA between 2010 and 2021, focusing on the effects of the COVID-19 pandemic. METHODS: We collected data from the National Vital Statistic System and calculated age-standardized mortality rates (ASMR) and cause-specific mortality for PsO/PsA. We evaluated observed versus predicted mortality for 2020-2021 based on trends from 2010 to 2019 with joinpoint and prediction modelling analysis. RESULTS: Among 5810 and 2150 PsO- and PsA-related deaths between 2010 and 2021, ASMR for PsO dramatically increased between 2010-2019 and 2020-2021 (annual percentage change [APC] 2.07% vs. 15.26%; p < 0.01), leading to a higher observed ASMR (per 100,000 persons) than predicted for 2020 (0.27 vs. 0.22) and 2021 (0.31 vs. 0.23). The excess mortality of PsO was 22.7% and 34.8% higher than that in the general population in 2020 (16.4%, 95% CI: 14.9%-17.9%) and 2021 (19.8%, 95% CI: 18.0%-21.6%) respectively. Notably, the ASMR rise for PsO was most pronounced in the female (APC: 26.86% vs. 12.19% in males) and the middle-aged group (APC: 17.67% vs. 12.47% in the old-age group). ASMR, APC and excess mortality for PsA were similar to PsO. SARS-CoV-2 infection contributed to more than 60% of the excess mortality for PsO and PsA. CONCLUSIONS: Individuals living with PsO and PsA were disproportionately affected during the COVID-19 pandemic. Both ASMRs increased at an alarming rate, with the most pronounced disparities among the female and middle-aged groups.

A Multiresponsive Functional AIEgen for Spatiotemporal Pattern Control and All-round Information Encryption.

Functional materials with multi-responsive properties and good controllability are highly desired for developing bioinspired and intelligent multifunctional systems. Although some chromic molecules have been developed, it is still challenging to realize in situ multicolor fluorescence changes based on a single luminogen. Herein, we reported an aggregation-induced emission (AIE) luminogen called CPVCM, which can undergo a specific amination with primary amines to trigger luminescence change and photoarrangement under UV irradiation at the same active site. Detailed mechanistic insights were carried out to illustrate the reactivity and reaction pathways. Accordingly, multiple-colored images, a quick response code with dynamic colors, and an all-round information encryption system were demonstrated to show the properties of multiple controls and responses. It is believed that this work not only provides a strategy to develop multiresponsive luminogens but also develops an information encryption system based on luminescent materials.

Regulatory mechanism of androgen receptor on NCAPD3 gene expression in prostate cancer.

BACKGROUND: Androgen receptor (AR) is an essential transcriptional factor that contributes to the development and progression of prostate cancer (PCa). NCAPD3 is a component of the condensin II complex and plays a critical role in cell mitosis by regulating chromosome condensation; however, the relationship between NCAPD3 and AR remains unknown. METHODS: Transcriptome sequencing assay is carried out to analyze the expression of the NCAP family in clinic samples. Chromatin immunoprecipitation (ChIP) sequencing, ChIP assay, and dual-luciferase assay are used to identify the androgen-responsive element in NCAPD3 enhancer. Immunohistochemistry, quantitative reverse transcription-polymerase chain reaction, and western-blot assay are employed to check the expression of genes in PCa tissues and in PCa cells. Confocal immunofluorescence microscopy analysis is used for identifying the regulation of AR on NCAPD3-mediated chromosome condensation. Colony formation, cell cycle assay, wound healing assay, and transwell experiments are used to explore the regulation of AR on the functions of NCAPD3. In vivo experiment is employed to identify in vitro experimental results. RESULTS: NCAPD3 is an androgen/AR axis-targeted gene and is involved in AR-induced PCa cell proliferation, migration, and invasion in vitro and in vivo. Androgen treatment and AR overexpression increase the expression of NCAPD3 in PCa cell lines. The canonical exist in the enhancer region of NCAPD3. Androgen/AR axis regulates NCAPD3-invovled chromosome condensation during cell mitosis. CONCLUSIONS: Our report demonstrated that NCAPD3 is an androgen-responsive gene and upregulated by androgen/AR axis and involved in AR-promoted progression of PCa, suggesting a potential role of NCAPD3 in the PCa development.

Direct biosynthesis of adipic acid from lignin-derived aromatics using engineered Pseudomonas putida KT2440.

Lignin is one largely untapped natural resource that can be exploited as a raw material for the bioproduction of value-added chemicals. Meanwhile, the current petroleum-based process for the production of adipic acid faces sustainability challenges. Here we report the successful engineering of Pseudomonas putida KT2440 strain for the direct biosynthesis of adipic acid from lignin-derived aromatics. The devised bio-adipic acid route features an artificial biosynthetic pathway that is connected to the endogenous aromatics degradation pathway of the host at the branching point, 3-ketoadipoyl-CoA, by taking advantage of the unique carbon skeleton of this key intermediate. Studies of the metabolism of 3-ketoadipoyl-CoA led to the discovery of crosstalk between two aromatics degradation pathways in KT2440. This knowledge facilitated the formulation and implementation of metabolic engineering strategies to optimize the carbon flux into the biosynthesis of adipic acid. By optimizing pathway expression and cultivation conditions, an engineered strain AA-1 produced adipic acid at 0.76 g/L and 18.4% molar yield under shake-flask conditions and 2.5 g/L and 17.4% molar yield under fermenter-controlled conditions from common aromatics that can be derived from lignin. This represents the first example of the direct adipic acid production from model compounds of lignin depolymerization.

Ultrasensitive Detection of Aminopeptidase N Activity in Urine and Cells with a Ratiometric Fluorescence Probe.

An ultrasensitive ratiometric fluorescent probe (CVN) has been designed and synthesized by incorporating alanine into the cresyl violet fluorophore. The probe shows ratiometric fluorescence response toward aminopeptidase N (APN) through the increase of fluorescent intensity ratio of 626/575 nm. The sensitivity of the probe is ultrahigh with a detection limit of 33 pg/mL, which can quantify the contents of APN in 500-fold diluted human urine samples. Furthermore, by using ratiometric fluorescence imaging, the probe reveals significantly higher contents of APN in HepG2 cells than those in LO2 cells, which has been further used to distinguish these two types of cells in mixed cocultures. The probe could be of great importance for the APN-related disease diagnosis and pathophysiology elucidation.

Facile and Sensitive Method for Protein Kinase A Activity Assay Based on Fluorescent Off-On PolyU-peptide Assembly.

Phosphorylation mediated by protein kinases plays a pivotal role in metabolic and cell-signaling processes, and the dysfunction of protein kinases such as protein kinase A (PKA) may induce several human diseases. Therefore, it is of great significance to develop a facile and effective method for PKA activity assay and high-throughput screening of inhibitors. Herein, we develop a new fluorescent off-on method for PKA assay based on the assembly of anionic polyuridylic acid (polyU) and cationic fluorescent peptide. The phosphorylation of the peptide disrupts its electrostatic binding with polyU, suppresses the concentration quenching effect of polyU, and thus causes fluorescence recovery. The recovered fluorescence intensity at 585 nm is directly proportional to the PKA activity in the range of 0.1-3.2 U/mL with a detection limit of 0.05 U/mL. Using our method, the PKA activity in HeLa cell lysate is determined to be 58.2 ± 5.1 U/mg protein. The method has also been employed to evaluate the inhibitory effect of PKA inhibitors with satisfactory results and may be expected to be a promising candidate for facile and cost-effective assay of kinase activity and high-throughput inhibitor screening.