Natural Product Quercetin-3-methyl ether Promotes Colorectal Cancer Cell Apoptosis by Downregulating Intracellular Polyamine Signaling.

Dysregulation of cellular metabolism is a key marker of cancer, and it is suggested that metabolism should be considered as a targeted weakness of colorectal cancer. Increased polyamine metabolism is a common metabolic change in tumors. Thus, targeting polyamine metabolism for anticancer therapy, particularly polyamine blockade therapy, has gradually become a hot topic. Quercetin-3-methyl ether is a natural compound existed in various plants with diverse biological activities like antioxidant and antiaging. Here, we reported that Quercetin-3-methyl ether inhibits colorectal cancer cell viability, and promotes apoptosis in a dose-dependent and time-dependent manner. Intriguingly, the polyamine levels, including spermidine and spermine, in colorectal cancer cells were reduced upon treatment of Quercetin-3-methyl ether. This is likely resulted from the downregulation of SMOX, a key enzyme in polyamine metabolism that catalyzes the oxidation of spermine to spermidine. These findings suggest Quercetin-3-methyl ether decreases cellular polyamine level by suppressing SMOX expression, thereby inducing colorectal cancer cell apoptosis. Our results also reveal a correlation between the anti-tumor activity of Quercetin-3-methyl ether and the polyamine metabolism modulation, which may provide new insights into a better understanding of the pharmacological activity of Quercetin-3-methyl ether and how it reprograms cellular polyamine metabolism.

Unraveling the dynamics of firing patterns for neurons with impairment of sodium channels.

Various factors such as mechanical trauma, chemical trauma, local ischemia, and inflammation can impair voltage-gated sodium channels (Nav) in neurons. These impairments lead to a distinctive leftward shift in the activation and inactivation curves of voltage-gated sodium channels. The resulting sodium channel impairments in neurons are known to affect firing patterns, which play a significant role in neuronal activities within the nervous system. However, the underlying dynamic mechanism for the emergence of these firing patterns remains unclear. In this study, we systematically investigated the effects of sodium channel dysfunction on individual neuronal dynamics and firing patterns. By employing codimension-1 bifurcation analysis, we revealed the underlying dynamical mechanism responsible for the generation of different firing patterns. Additionally, through codimension-2 bifurcation analysis, we theoretically determined the distribution of firing patterns on different parameter planes. Our results indicate that the firing patterns of impaired neurons are regulated by multiple parameters, with firing pattern transitions caused by the degree of sodium channel impairment being more diverse than those caused by the ratio of impaired sodium channel and current. Furthermore, we observed that the firing pattern of tonic firing is more likely to be the norm in impaired sodium channel neurons, providing valuable insights into the signaling of impaired neurons. Overall, our findings highlight the intricate relationships among sodium channel impairments, neuronal dynamics, and firing patterns, shedding light on the impact of disruptions in ion concentration gradients on neuronal function.

Multifunctional Starch-Based Sensor with Non-Covalent Network to Achieve "3R" Circulation.

With the consumption of disposable electronic devices increasing, it is meaningful but also a big challenge to develop reusable and sustainable materials to replace traditional single-use sensors. Herein, a clever strategy for constructing a multifunctional sensor with 3R circulation (renewable, reusable, pollution-reducing biodegradable) is presented, in which silver nanoparticles (AgNPs) with multiple interactions are introduced into a reversible non-covalent cross-linking network composed of biocompatible and degradable carboxymethyl starch (CMS) and polyvinyl alcohol (PVA) to simultaneously obtain high mechanical conductivity and long-term antibacterial properties by a one-pot method. Surprisingly, the assembled sensor shows high sensitivity (gauge factor up to 4.02), high conductivity (0.1753 S m-1 ), low detection limit (0.5%), long-term antibacterial ability (more than 7 days), and stable sensing performance. Thus, the CMS/PVA/AgNPs sensor can not only accurately monitor a series of human behavior, but also identify handwriting recognition from different people. More importantly, the abandoned starch-based sensor can form a 3R circulation. Especially, the fully renewable film still shows excellent mechanical performance, achieving reusable without sacrificing its original function. Therefore, this work provides a new horizon for multifunctional starch-based materials as sustainable substrates for replacing traditional single-use sensors.

Genetic analysis and biological characterization of H10N3 influenza A viruses isolated in China from 2014 to 2021.

The H10 subtypes of avian influenza viruses pose a continual threat to the poultry industry and human health. The sporadic spillover of H10 subtypes viruses from poultry to humans is represented by the H10N8 human cases in 2013 and the recent H10N3 human infection in 2021. However, the genesis and characteristics of the recent reassortment H10N3 viruses have not been systemically investigated. In this study, we characterized 20 H10N3 viruses isolated in live poultry markets during routine nationwide surveillance in China from 2014 to 2021. The viruses in the recent reassortant genotype acquired their hemagglutinin (HA) and neuraminidase (NA) genes from the duck H10 viruses and H7N3 viruses, respectively, whereas the internal genes were derived from chicken H9N2 viruses as early as 2019. Receptor-binding analysis indicated that two of the tested H10N3 viruses had a higher affinity for human-type receptors than for avian-type receptors, highlighting the potential risk of avian-to-human transmission. Animal studies showed that only viruses belonging to the recent reassortant genotype were pathogenic in mice; two tested viruses transmitted via direct contact and one virus transmitted by respiratory droplets in guinea pigs, though with limited efficiency. These findings emphasize the need for enhanced surveillance of H10N3 viruses.

Multiple/Two-Way Shape Memory Poly(urethane-urea-amide) Elastomers.

Multiple and two-way reversible shape memory polymers (M/2W-SMPs) are highly promising for many fields due to large deformation, lightweight, strong recovery stress, and fast response rates. Herein, a semi-crystalline block poly(urethane-urea-amide) elastomers (PUUAs) are prepared by the copolymerization of isocyanate-terminated polyurethane (OPU) and amino-terminated oligomeric polyamide-1212 (OPA). PUUAs, composed of OPA as stationary phase and PTMEG as reversible phase, exhibit excellent rigidity, flexibility, and resilience, and cPUUA-C7 -S25 exhibits the best tensile property with strength of 10.3 MPa and elongation at break of 360.2%. Besides, all the PUUAs possess two crystallization/melting temperatures and a glass transition temperature, which endow PUUAs with multiple and reversible two-way shape memory effect (M/2W-SME). Physically crosslinked PUUA-C0 -S25 exhibits excellent dual and triple shape memory, and micro chemically crosslinked cPUUA-C7 -S25 further shows quadruple shape memory behavior. Additionally, both PUUA-C0 -S25 and cPUUA-C7 -S25 have 2W-SME. Intriguingly, cPUUA-C7 -S25 can achieve a higher temperature (up to 165 °C) SME, which makes it suitable for more complex and changeable applications. Based on the advantages of M/2W-SME, a temperature-responsive application scenario where PUUAs can transform spontaneously among different shapes is designed. These unique M/2W-SME and high-temperature SME will enable the applications of high-temperature sensors, actuators, and aerospace equipment.

Analysis of avian influenza A (H3N8) viruses in poultry and their zoonotic potential, China, September 2021 to May 2022.

BackgroundTwo human cases of avian influenza A (H3N8) virus infection were reported in China in 2022.AimTo characterise H3N8 viruses circulating in China in September 2021-May 2022.MethodsWe sampled poultry and poultry-related environments in 25 Chinese provinces. After isolating H3N8 viruses, whole genome sequences were obtained for molecular and phylogenetic analyses. The specificity of H3N8 viruses towards human or avian receptors was assessed in vitro. Their ability to replicate in chicken and mice, and to transmit between guinea pigs was also investigated.ResultsIn total, 98 H3N8 avian influenza virus isolates were retrieved from 38,639 samples; genetic analysis of 31 representative isolates revealed 17 genotypes. Viruses belonging to 10 of these genotypes had six internal genes originating from influenza A (H9N2) viruses. These reassorted viruses could be found in live poultry markets and comprised the strains responsible for the two human infections. A subset of nine H3N8 viruses (including six reassorted) that replicated efficiently in mice bound to both avian-type and human-type receptors in vitro. Three reassorted viruses were shed by chickens for up to 9 days, replicating efficiently in their upper respiratory tract. Five reassorted viruses tested on guinea pigs were transmissible among these by respiratory droplets.ConclusionAvian H3N8 viruses with H9N2 virus internal genes, causing two human infections, occurred in live poultry markets in China. The low pathogenicity of H3N8 viruses in poultry allows their continuous circulation with potential for reassortment. Careful monitoring of spill-over infections in humans is important to strengthen early-warning systems and maintain influenza pandemic preparedness.

Towards MOFs' mass market adoption: MOF Technologies' efficient and versatile one-step extrusion of shaped MOFs directly from raw materials.

Metal Organic Frameworks (MOFs) offer unparalleled physical and sorption properties due to their chemical tunability and unmatched porosity. MOFs are consequently envisaged to play a key role in commercial gas storage and separation applications. However, it is essential to tackle their current market entry barriers, if mainstream adoption is to be realised. MOF Technologies is a pioneer in MOF commercialisation and has developed innovative solutions with unprecedented efficiency to bring these materials to market. A continuous, versatile and sustainable one-step production method of MOFs in shaped form is demonstrated for the first time. Its advantages for large-scale production and mass customisation are exemplified and validated with performance evaluation under realistic operating conditions.

pH Responsive Strong Polyion Complex Shape Memory Hydrogel with Spontaneous Shape Changing and Information Encryption.

Polyion complex (PIC) hydrogels attract lots of studies because of the relatively definite network and excellent mechanical strength. However, the stability of the PIC hydrogel is poor in salt solutions due to the counter-ion screening effect, which restricts their applications. Besides, novel functions of the PIC hydrogels also need to be explored. In this work, a multifunctional PIC hydrogel is prepared by polymerizing a hydrophobic monomer 2-(diethylamino)ethyl methacrylate in poly(styrene sulfonic acid) aqueous solution with the presence of counter-ion NaCl. Fourier transform infrared (FTIR) spectra, water content, and mechanical properties of the hydrogel are investigated. The introduction of hydrophobic weak electrolyte into the hydrogel brings stable excellent mechanical strength even in NaCl solutions with high concentration and pH modulated softening and strengthening. Surprisingly, the hydrogel swells but is strengthened in HCl, while it shrinks but is softened in NaOH. pH induced shape memory and unique spontaneous shape changing is thus presented benefiting from this synergistic effect. Moreover, information encryption is realized on the PIC hydrogel owing to the transmittance change and the different water absorption capability of the hydrogel at different states. This new kind of PIC hydrogel proposes a new smart material in continuously actuating soft machines and secretive information transformation.

Elastin-Based Thermoresponsive Shape-Memory Hydrogels.

A shape-memory hydrogel is a programmable hydrogel material that can store specific shapes and execute functions in response to stimuli. In this report, we developed shape-memory hydrogels by creating double-network polymeric structures using a physically cross-linking elastin-like polypeptide (ELP) and a chemically cross-linking polyacrylamide (PAM). We synthesized the hydrogel matrix by polymerizing the acrylamide mixed in an ELP solution. We exploited the lower critical solution temperature transition of the ELP to enable the hydrogel to hold a new desired shape at an elevated temperature of 55 °C. The original shape of the hydrogel can then be recovered by lowering the temperature to 20 °C. The shape-memory hydrogels we developed exhibit ultrafast functionality and high repeatability. Taking advantage of the temperature-induced shape-memory capability, we also demonstrate practical functions such as gripping an object and connecting two tubes. Our materials with effective temperature-driven shape-memory functionality will be useful for developing novel materials for biomedical applications in the future.

Combinational Hydrogel and Xerogel Actuators Showing NIR Manipulating Complex Actions.

Near-infrared (NIR)-driven shape memory hydrogels are synthesized with a one-pot polymerization of N,N-dimethylacrylamide in the inorganic clay and graphene oxide (GO) suspension. The hydrogel consists of only a physically crosslinked network, which is partially thermoreversible. With the efficient photothermal energy transformation of GO in the hydrogels, the shape recovery from the temporal shape is achieved by NIR irradiation. The optimal shape fixing percentage and recovery rate are found at moderate monomer and crosslinker contents. Meanwhile, the xerogel dried from the hydrogel also shows a fast NIR response shape change. The NIR manipulating combinational hydrogel-xerogel actuators are prepared by combining the wet and soft hydrogel and its dry and rigid xerogel together. The actuators achieve complex actions of turning and lifting under sequential NIR irradiation to carry an object up- and downward and around obstacles, or to transfer an object to a target position. This work provides a new idea for designing combinational actuators to fulfil complex actions.

Sequential correction technique to avoid postoperative global coronal decompensation in rigid adult spinal deformity: a technical note and preliminary results.

PURPOSE: This study aims to evaluate this new sequential correction technique for preventing postoperative coronal imbalance. METHODS: Adult Spinal deformity (ASD) patients were stratifies into two types: primary thoracolumbar/lumbar (TL/L) curve with compensatory lumbosacral (LS) curve (Type I) and primary LS curve with compensatory TL/L curve (Type II): for Type I patients: correction of major TL/L curve and one- or two-level segmental rod installed at the convexity of the TL/L curve, L4-S1 TLIF to correct fractional curve and a short rod installed on the contralateral side and installation of long rods; for Type II patients: horizontalize L4 and L5, short rod installation at the convexity of the LS curve, distraction of curve with regional rod and installation of long rods. ASD patients were enrolled with inclusion criteria: with pre-op TL/L Cobb angle more than 30°, with pelvic fixation and with UIV over T10. Radiographic parameters were analyzed. RESULTS: Twenty-one patients were recruited (14 patients Type I and 7 Type II patients). Both Cobb angle and coronal offset were significantly improved after surgery. In Type I patients, Cobb angle was improved from 50.48° to 26.91° and coronal offset from 2.94 to 0.95 cm; in Type II patients, Cobb angle was improved from 61.42° to 28.48° and coronal offset from 2.82 to 1.38 cm. In the 10 patients with baseline coronal imbalance, 9 were corrected to coronal balance after surgery. CONCLUSION: The sequential correction technique allows decomposing the complex correction surgery into several steps, and each step focuses only on one task. It can also reduce the difficulty of rod installation due to the separated maneuvers and multi-rod system. LEVEL OF EVIDENCE: IV These slides can be retrieved under Electronic Supplementary Material.

Could pelvic parameters determine optimal postoperative thoracic kyphosis in Lenke type 1 AIS patients?

BACKGROUND: A proper restoration of sagittal alignment is essential in AIS patients, but few studies provided a formula to predict an optimal surgical thoracic kyphosis (TK) gain in adolescent idiopathic scoliosis (AIS) patients. A formula was recently proposed (LL = (PI+TK)/2 + 10) to predict the optimal lumbar lordosis (LL) in adult spinal deformity patients, which has not been validated in adolescents. The aim of this study is to establish a formula with TK and pelvic parameters in normal adolescents and predict an optimal TK with this formula pre- and post-operatively in Lenke 1 AIS patients. METHODS: A total of 60 asymptomatic adolescents were used to validate the proposed formula. The subject was considered to match with the formula, if the difference between the virtual TK and the theoretical TK was less than 10°. Then regression analysis was performed to establish a new formula to predict TK in adolescents. The predictive efficiency of the new formula was also validated in 40 Lenke 1 AIS patients. RESULTS: Of the 60 asymptomatic adolescents, only 26 (43.33%) asymptomatic adolescents matched with the adjusted formula: TK = 2 × (LL-10)-PI. The paired t test revealed a significantly different theoretical TK (tTK) compared to the virtual TK (41.23 ± 18.29° vs. 24.80 ± 8.75°, P < 0.001). Multiple linear regression showed that TK had a relationship with LL, SS and age (R2 = 0.331): TK = - 0.785 × LL-0.843 × SS + 0.858 × age + 3.754. There were 27 (67.50%), 32 (80.00%) and 35 (87.50%) Lenke 1 AIS patients matched this formula preoperatively, postoperatively and at the last follow-up. CONCLUSION: Our results revealed that the predictive formula for sagittal alignment for adults was not applicable in adolescents. This study established a new predictive formula for TK based on asymptomatic adolescents. In Lenke 1 AIS patients, post-op TK in 87.5% of patients matched the predictive value, indicating that the new formula can be considered as a reference when making a surgery strategy.

In Situ Monitoring and Mechanism of the Mechanochemical Formation of a Microporous MOF-74 Framework.

Mechanochemistry provides a rapid, efficient route to metal-organic framework Zn-MOF-74 directly from a metal oxide and without bulk solvent. In situ synchrotron X-ray diffraction monitoring of the reaction course reveals two new phases and an unusual stepwise process in which a close-packed intermediate reacts to form the open framework. The reaction can be performed on a gram scale to yield a highly porous material after activation.

Surface Molding Hydrogel Film Initiated by ZIF-8 with Ethylene Adsorption Performance for Preserving Perishable Fruits.

The quality deterioration of postharvest fruits is greatly influenced by ethylene, leading to food wastage worldwide. Therefore, it is urgent to develop an efficient packaging strategy to reduce ethylene concentration and prolong the shelf life of perishable fruits. In this work, a surface-molding hydrogel film was created using ZIF-8 in combination with carboxymethyl starch (CMS) and carboxymethyl chitosan (CMCS). Specifically, ZIF-8 is first anchored on CMS and then rapidly cross-linked in situ with CMCS, forming ZIF-8@CC on the fruit surface (within 10 s). The perfect tight-fitting effects of ZIF-8@CC were observed on various fruit surfaces with different roughness (Ra: ranges from 102 to 308 nm). ZIF-8@CC could absorb 57.3% endogenous ethylene from bananas, and the interaction mechanism between ethylene and ZIF-8 was studied by molecular dynamics simulations, providing insights into the ethylene adsorption capacity of ZIF-8@CC. Moreover, ZIF-8@CC presented excellent antibacterial properties and achieved satisfactory ultralong preservation effects on both nonclimatic and climatic fruits (12 days for strawberries and 14 days for bananas) at room temperature. Importantly, ZIF-8@CC is easily removed, washed, and degradable. These findings offer an efficient and potential food packing material with multifunctional properties for preserving perishable fruits.

A co-type ductile film with high tensile strength and fast self-healing properties for shaped fruit preservation.

Traditional petroleum-based plastics have high energy consumption, require professional equipment, are non-degradable after use, and lack antibacterial properties, making it impossible to achieve long-lasting freshness in fruits and vegetables. Herein, we report a novel co-type film-forming method with low energy consumption and without production equipment, which uses PVA-borax gel as a substrate and adds a certain proportion of CMC and TA to prepare multifunctional CMC/TA@PVA-borax composite hydrogels (CTPB). The dynamic borax ester bonding and hydrogen bonding in the CTPB hydrogel results in an ultra-high tensile strength of more than 5500% and rapid self-healing within 8 s. Interestingly, hydrogels can be arbitrarily shaped and stretched like play dough and thus can be stretched into ductile films by co-type film formation. The antimicrobial properties of the hydrogel film can be attributed to the synergistic effects of TA and borax. The mussel structure of TA allows the hydrogel film to adhere directly to different surfaces for more effective bacterial killing. In addition, the hydrogel film has a high level of biosafety and biodegradability and shows good performance in fruit storage. This study provides a convenient and low-energy method for the preparation of films, which in part reduces the increasing environmental pollution caused by petroleum-based plastics.

Super protective effect, ultra-high juice absorption and long-term antibacterial of Ag-2MI@Chitosan biodegradable sponge for fruit preservation and transportation.

Plastic foam packaging is often used for the transportation to avoid mechanical damage to the fruit, but it lacks antibacterial properties, water absorption and is non-degradable, leading to fruit decay and safety risks as well as serious environmental pollution. Herein, Ag-2-Methylimidazole@Chitosan (Ag-2MI@CS) was successfully synthesized by in situ synthesis at normal temperature and pressure, and improved the antibacterial performance of Ag-2MI@CS by using green solvent ethanol to adjust the solvent polarity. The results showed that the long-lasting inhibitory performance of Ag-2MI@CS was significantly improved, the long-lasting antibacterial time has been extended from 24 h to 96 h. Furthermore, Ag-2MI@CS can significantly protect fruits and reduce the damage of fruits, even when falling from a height of 60 cm or under extreme transportation conditions. Besides, Ag-2MI@CS had extremely high absorption rates of water and fruit juice, 1447.69 % and 1356.59 %, respectively, which was conducive to absorbing water generated by respiration and juice generated by damage during transportation, so as to avoid the growth of bacteria caused by water and fruit juice. Ag-2MI@CS can achieve fruit preservation in both indoor static and transportation dynamic conditions. This study offers novel insights into new biodegradable packaging material in fruit transportation.

Gait function assessed using 3D gait analysis in patients with cervical spinal myelopathy before and after surgical decompression: a systematic review and meta-analysis.

BACKGROUND: Degenerative cervical myelopathy (DCM) is the most common cause of cervical spinal cord dysfunction in adults and the result of chronic degenerative changes of the cervical spine. The compression of the spinal cord can lead to ischemia, inflammation, and neuronal apoptosis with a consequent impairment of the neurological function. Gait impairment is one of the most frequent signs of DCM. PURPOSE: To investigate the changes in spatio-temporal gait parameters assessed using 3D gait analysis in patients affected by DCM compared with healthy controls and the effect of surgical decompression on these parameters. STUDY DESIGN/SETTING: Systematic review and meta-analysis. PATIENT SAMPLE: The meta-analysis included 267 patients with DCM and 276 healthy controls. OUTCOME MEASURES: Spatio-temporal parameters of gait were assessed. The primary outcome was gait speed; the secondary outcomes were cadence, stride length, step width, stride time, single-limb support time, and double-limb support time. METHODS: Studies reporting spatial and/or temporal gait parameters measured using 3D gait analysis in patients with DCM were included. Data sources were Embase, Medline, and the Core Collection of Web of Science. Meta-analyses were performed to investigate the influence of surgical decompression in patients measured before and after surgery as well as to compare gait parameters of patients with DCM with controls. RESULTS: Thirteen studies reporting on 267 patients with DCM and 276 healthy controls met the inclusion criteria. Seven studies compared patients with DCM with healthy controls, three studies compared gait in patients with DCM before and after surgical decompression, and three studies performed both comparisons. Compared with healthy controls, patients with DCM had slower gait speed (Standardized Mean Difference (SMD), -1.49; 95% confidence interval (CI) [-1.86; -1.13]; p<.001), lower cadence (SMD, -0.78; 95%CI [-1.00; -0.56]; p<.001), shorter stride length (SMD, -1.27; 95%CI [-1.53, -1.01]; p<.001), greater step width (SMD, 0.98; 95%CI [0.42, 1.54]; p=.003), longer stride time (SMD, 0.77; 95%CI [0.37, 1.16]; p=.009), single-limb support phase (SMD, -0.68; 95%CI [-1.06; -0.29]; p=.011), and double-limb support phase (SMD 0.84; 95%CI [0.35, 1.32]; p=.012). After surgical decompression, patients with DCM showed an improvement in gait speed (SMD, 0.57 (95%CI [0.29; 0.85]; p=.003) and no significant differences in other spatio-temporal parameters. CONCLUSIONS: Patients with DCM have clearly different spatio-temporal gait parameters than healthy controls. Gait speed is the only spatio-temporal gait parameter that improves significantly after surgical decompression suggesting that gait speed may be an important clinical outcome parameter in patients with DCM.

One-pot co-crystallized hexanal-loaded ZIF-8/quaternized chitosan film for temperature-responsive ethylene inhibition and climacteric fruit preservation.

Controlling ethylene production and microbial infection are key factors to prolong the shelf life of climacteric fruit. Herein, a nanocomposite film, hexanal-loaded ZIF-8/CS (HZCF) with "nano-barrier" structure, was developed by a one-pot co-crystallized of ZIF-8 in situ growth on quaternized chitosan (CS) and encapsulation of hexanal into ZIF-8 via microporous adsorption. The resultant film realized the temperature responsive release of hexanal via the steric hindrance and hierarchical pore structure as "nano-barrier", which can inhibit ethylene production in climacteric fruit on demand. Based on this, the maximum ethylene inhibition rate of HZCF was up to 52.6 %. Meanwhile, the film exhibits excellent antibacterial, mechanical, UV resistance and water retention properties, by virtue of the functional synergy between ZIF-8 and CS. Contributed to the multifunctional features, HZCF prolonged the shelf life of banana and mango for at least 16 days, which is 8 days longer than that of control fruit. More strikingly, HZCF is washable and biodegradable, which is expected to replace non-degradable plastic film. Thus, this study provides a convenient novel approach to simplify the encapsulation of active molecule on metal-organic frameworks (MOFs), develops a packaging material for high-efficient freshness preservation, and helps to alleviate the survival crisis caused by food waste.

Evolution and biological characterization of H5N1 influenza viruses bearing the clade 2.3.2.1 hemagglutinin gene.

H5N1 avian influenza viruses bearing the clade 2.3.2.1 hemagglutinin (HA) gene have been widely detected in birds and poultry in several countries. During our routine surveillance, we isolated 28 H5N1 viruses between January 2017 and October 2020. To investigate the genetic relationship of the globally circulating H5N1 viruses and the biological properties of those detected in China, we performed a detailed phylogenic analysis of 274 representative H5N1 strains and analyzed the antigenic properties, receptor-binding preference, and virulence in mice of the H5N1 viruses isolated in China. The phylogenic analysis indicated that the HA genes of the 274 viruses belonged to six subclades, namely clades 2.3.2.1a to 2.3.2.1f; these viruses acquired gene mutations and underwent complicated reassortment to form 58 genotypes, with G43 being the dominant genotype detected in eight Asian and African countries. The 28 H5N1 viruses detected in this study carried the HA of clade 2.3.2.1c (two strains), 2.3.2.1d (three strains), or 2.3.2.1f (23 strains), and formed eight genotypes. These viruses were antigenically well-matched with the H5-Re12 vaccine strain used in China. Animal studies showed that the pathogenicity of the H5N1 viruses ranged from non-lethal to highly lethal in mice. Moreover, the viruses exclusively bound to avian-type receptors and have not acquired the ability to bind to human-type receptors. Our study reveals the overall picture of the evolution of clade 2.3.2.1 H5N1 viruses and provides insights into the control of these viruses.

A broad-spectrum vaccine candidate against H5 viruses bearing different sub-clade 2.3.4.4 HA genes.

The global spread of H5 clade 2.3.4.4 highly pathogenic avian influenza (HPAI) viruses threatens poultry and public health. The continuous circulation of these viruses has led to their considerable genetic and antigenic evolution, resulting in the formation of eight subclades (2.3.4.4a-h). Here, we examined the antigenic sites that determine the antigenic differences between two H5 vaccine strains, H5-Re8 (clade 2.3.4.4g) and H5-Re11 (clade 2.3.4.4h). Epitope mapping data revealed that all eight identified antigenic sites were located within two classical antigenic regions, with five sites in region A (positions 115, 120, 124, 126, and 140) and three in region B (positions 151, 156, and 185). Through antigenic cartography analysis of mutants with varying numbers of substitutions, we confirmed that a combination of mutations in these eight sites reverses the antigenicity of H5-Re11 to that of H5-Re8, and vice versa. More importantly, our analyses identified H5-Re11_Q115L/R120S/A156T (H5-Re11 + 3) as a promising candidate for a broad-spectrum vaccine, positioned centrally in the antigenic map, and offering potential universal protection against all variants within the clade 2.3.4.4. H5-Re11 + 3 serum has better cross-reactivity than sera generated with other 2.3.4.4 vaccines, and H5-Re11 + 3 vaccine provided 100% protection of chickens against antigenically drifted H5 viruses from various 2.3.4.4 antigenic groups. Our findings suggest that antigenic regions A and B are immunodominant in H5 viruses, and that antigenic cartography-guided vaccine design is a promising strategy for selecting a broad-spectrum vaccine.