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At least 19 recordsLinked to original sources
PubMed2025

African Swine Fever Virus MGF 360-2L Disrupts Host Antiviral Immunity Based on Transcriptomic Analysis.

Background/Objectives: The African swine fever virus (ASFV) multi-gene family (MGF) 360 proteins play critical roles in immune evasion, replication regulation, and virulence determination. Despite substantial advances in this field, the functional roles of many members within this gene family remain to be fully characterized. Methods: In this study, Transcriptional kinetics analysis indicated that the expression profile of MGF 360-2L was consistent with that of the late marker gene B646L (p72). Transcriptomic profiling identified 13 and 171 differentially expressed genes (DEGs) at 12 and 24 h post-infection (hpi) with ΔMGF 360-2L, respectively. Results: Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses indicated that these DEGs were predominantly enriched in Type I interferon (IFN-I) signaling pathways. It is noteworthy that transcriptome analysis further demonstrates that the absence of MGF 360-2L specifically results in the dysregulation of expression of the replication-essential genes E199L and E301R. These findings indicate that MG F360-2L is essential for maintaining the stable expression of these proteins. Conclusions:MGF 360-2L is a late gene that contributes to the precise regulation of viral protein expression and modulates the host immune response during infection.

African swine fever virus↗
PubMed1978

Physical mapping of herpes simplex virus-coded functions and polypeptides by marker rescue and analysis of HSV-1/HSV-2 intertypic recombinants.

A number of temperature-sensitive (ts) mutants and one pyrimidine deoxyribonucleoside kinase-deficient mutant of herpes simplex virus (HSV), have been located on the physical map of the genome by means of marker rescue experiments and by the analysis of the crossover points in intertypic recombinants between HSV types 1 and 2. The physical map is compared to the genetic map and certain anomalies identified. Analysis of infected-cell polypeptides specified by intertypic recombinants has allowed tentative map co-ordinates to be assigned to the structural genes (or genes which cause post-translational modification) for many of the polypeptides. Immediate-early, phosphorylated, glycosylated and structural as well as non-structural polypeptides have been analysed in this way and it can be concluded that there is no restriction of any of these groups of polypeptides to either the long or the short regions of the genome. One of the recombinants, 2853, is at least partially "frozen" in one orientation of the long region. This orientation is also the one which exhibits a minimum number of crossovers in three other recombinants.

Chromosome Mapping↗
PubMed1978

Anatomy of herpes simplex virus (HSV) DNA. X. Mapping of viral genes by analysis of polypeptides and functions specified by HSV-1 X HSV-2 recombinants.

In an earlier paper (Morse et al., J. Virol 24:231--248, 1977) we reported on the provenance of the DNA sequences in 26 herpes simplex virus type 1 (HSV-1) X HSV-2 recombinants as determined from analyses of their DNAs with at least five restriction endonucleases. This report deals with the polypeptides specified by the recombinants and by their HSV-1 and HSV-2 parents. We have identified (i) the corresponding HSV-1 and HSV-2 polypeptides with molecular weights ranging from 20,000 to more than 200,000, (ii) the polypeptides that undergo rapid post-translational processing, and (iii) polypeptides that vary intratypically in apparent molecular weight. By comparing the segregation patterns of the polypeptides with those of the DNA sequence of the recombinants, we have mapped the templates specifying 26 polypeptides and several viral functions on the physical map of HSV DNA. The data show the following: (i) alpha polypeptides map at the termini of the L and S components of the HSV DNA. Although alpha ICP 27 maps entirely within the reiterated region of the L component, the template for alpha ICP 4 may lie only in part within the reiterated sequences of the S component. Of note is the finding that cells infected with a recombinant that contains both HSV-1 and HSV-2 DNA sequences in the S component produced alpha ICP 4 of both HSV-1 and HSV-2. (ii) Templates specifying beta and gamma polypeptides map in the L component and appear to be randomly distributed. (iii) Thymidine kinase and resistance to phosphonoacetic acid mapped in the L component. In addition, we have taken advantage of the rapid inhibition of host protein synthesis characteristic of HSV-2 infections and syncytial plaque morphology to also map the template(s) responsible for these functions in the L component. The implications of the template arrangement in HSV DNA are discussed.

Base Sequence↗
PubMed2026

MARK1 suppresses infectious bursal disease virus replication via phosphorylating VP3.

Infectious bursal disease virus (IBDV) of the Birnaviridae family is a non-envelope, double-stranded RNA virus that encodes a VP3 protein with multiple functions, which controls viral genome replication, IFN-β production, and virus traffic in infected cells. Posttranslational modifications (PTMs), such as ubiquitination, of VP3 have been demonstrated for affecting its function and stability. To clarify the mechanism by which VP3 is regulated in IBDV infected cells, we focused on the phosphorylation of VP3. Mass spectrometry analysis identified that microtubule-affinity regulating kinases 1 (MARK1) was a kinase interacting protein of VP3. Inhibitory function of MARK1 in affecting viral replication was validated. We describe the phosphorylation event at the serine 130 (S130) and serine 163 (S163) residues of VP3 mediated by MARK1 via mass spectrometry analysis. Alanine replacement of the phosphorylation sites in VP3 significantly enhanced its RNA-binding activity. Additionally, the mutation of two serine residues led to remarkably improved in its polymerase-enhancing function. We then incorporated the two mutations to rescue recombinant IBDV. Viral growth curve analysis revealed that replication of mutant IBDV was significantly enhanced relative to wild type (WT) virus. In conclusion, we found that VP3 functions are specifically regulated by MARK1 mediated phosphorylation at S130 and S163 and that this regulation suppresses IBDV replication ultimately.

Infectious bursal disease virus↗
PubMed1977

Some properties of recombinants between type 1 and type 2 herpes simplex viruses.

Four intertypic recombinants of herpes simplex virus have been shown to possess genetic information for functions characteristic of each of the two parental types. The functions were identified by (a) polyacrylamide gel electrophoresis of purified virus particles and of polypeptides synthesized in cells infected with the recombinants and (b) analysis of antigenic sites interacting with type specific neutralizing antibody. The analysis shows that each recombinant possess a different combination of these type specific markers. Finally we have been unable to detect recombination between herpes simplex type 1 and pseudorabies viruses.

Animals↗
PubMed2026

Molecular characteristics, phylodynamics, and evolutionary changes of avian infectious bronchitis virus detected from chickens in Yunnan Province, 2021-2024.

Avian infectious bronchitis virus (IBV) is endemic in poultry flocks worldwide, posing a significant threat to the global poultry industry. Frequent mixing of free-range local chickens with introduced chickens in Yunnan Province, China, facilitates the transmission, recombination, and mutation of avian IBV, thereby complicating disease prevention and control. In this study, we aimed to investigate the presence of IBV in poultry populations in Yunnan Province. Samples were collected from live poultry markets (LPMs) and breeding farms, comprising 725 randomly sampled cloacal/fecal swabs and 55 tissue samples. IBV-positive samples were confirmed via polymerase chain reaction (PCR), with an overall positivity rate of 0.89% (7/780) for all tested samples. The positivity rate was 0.35% (2/564) in Kunming, 3.7% (2/54) in Zhaotong, 20% (1/5) in Yuxi, and 12.5% (2/16) in Baoshan, while no IBV was detected in samples from Lanping, Xichou, or Ninglang. Six IBV strains, including five GI-19 strains and one GVI-1 strain, were successfully isolated. Phylogenetic analysis further showed that the Yunnan GI-19 strains predominantly clustered with strains originating from Sichuan Province. Sequencing of the S1 gene revealed several amino acids substitutions per isolate in hypervariable regions HVR1-HVR3. Notably, a valine (V) and glycine (G) insertion between amino acid positions 88 and 89 was identified exclusively in isolate F210, a feature rarely reported in IBV. Protein-protein docking analysis indicated that the unique 88-89 insertion in isolate F210 S1 may alter its binding interactions with the host receptor ANPEP. Whole-genome comparison revealed that isolate YX3 shared 97.05% nucleotide identity with strain CK/CH/GX/YL17/2017 from Guangxi, whereas isolates Q47, F13, and F210 shared 96.40%-97.27% identity with strain CK/Henan/H1036/2021 from Henan. Recombination analysis detected obvious recombination events in isolates F13, F210, Q47, and YX3, with GI-22 strains serving as the major parental donors. These genetic characteristics, recombination patterns, and structural insights demonstrate the complex evolutionary dynamics of circulating IBV strains in Yunnan. Continuous molecular epidemiological surveillance combined with functional protein analysis is essential to monitor emerging variants and formulating targeted, effective disease control strategies.

Avian infectious bronchitis virus↗
PubMed1978

The use of intertypic recombinants for analysis of gene organization in herpes simplex virus.

Analysis of the DNA sequence arrangement and polypeptides specified by 28 HSV-1 x HSV-2 recombinants show the following: (i) Recombinants with heterogeneous L and S components or with heterogenous inverted repeats are viable. (ii) HSV-1 and HSV-2 genes appear to be functionally equivalent and with few exceptions co-linearly arranged. Co-linear DNA maps have been established. (iii) At most two arrangements of HSV DNA are capable of replication. This is consistant with current studies suggesting that sequence arrangements are the consequence of obligatory post-synthesis repair. (iv) alpha Polypeptides map at the termini of the L and S components of HSV DNA. Although alpha ICP 27 maps entirely within the reiterated region of the L component, the template for alpha ICP 4 may lie only in part within the reiterated sequences of the S component. Of note is the finding that cells infected with a recombinant that contains both HSV-1 and HSV-2 DNA sequences in the S component, produced alpha ICP 4 of both HSV-1 and HSV-2. (v) Templates specifying beta and gamma polypeptides may in the L component and appear to be randomly distributed. (vi) The genes specifying thymidine kinase, resistance to phosphonoacetic acid and syncytial plaque morphology mapped in the L component. In addition, we have taken advantage of the rapid inhibition of host protein synthesis to map the gene(s) specifying this inhibition in the L component.

Chromosome Mapping↗
PubMed2025

Natural self-attenuation of pathogenic viruses by deleting the silencing suppressor coding sequence for long-term plant-virus coexistence.

Potyviridae is the largest family of plant-infecting RNA viruses. All members of the family (potyvirids) have single-stranded positive-sense RNA genomes, with polyprotein processing as the expression strategy. The 5'-proximal regions of all potyvirids, except bymoviruses, encode two types of leader proteases: the serine protease P1 and the cysteine protease HCPro. However, their arrangement and sequence composition vary greatly among genera or even species. The leader proteases play multiple important roles in different potyvirid-host combinations, including RNA silencing suppression and virus transmission. Here, we report that viruses in the genus Arepavirus, which encode two HCPro leader proteases in tandem (HCPro1-HCPro2), can naturally lose the coding sequences for these two proteins during infection. Notably, this loss is associated with a shift in foliage symptoms from severe necrosis to mild chlorosis or even asymptomatic infections. Further analysis revealed that the deleted region is flanked by two short repeated sequences in the parental isolates, suggesting that recombination during virus replication likely drives this genomic deletion. Reverse genetic approaches confirmed that the loss of leader proteases weakens RNA silencing suppression and other critical functions. A field survey of areca palm trees displaying varied symptom severity identified a transitional stage in which full-length viruses and deletion mutants coexist in the same tree. Based on these findings, we propose a scenario in which full-length isolates drive robust infections and facilitate plant-to-plant transmission, eventually giving rise to leader protease-less variants that mitigate excessive damage to host trees, allowing long-term coexistence with the perennial host. To our knowledge, this is the first report of potyvirid self-attenuation via coding sequence loss.

Plant Diseases↗
PubMed2025

Diversity and evolutionary history of endogenous retroviruses in the genome of Manis pentadactyla.

Endogenous retroviruses (ERVs), remnants of ancient viral infections integrated into host genomes, serve as invaluable molecular fossils for studying viral evolution. In this study, we performed a genomic analysis of the Chinese pangolin (Manis pentadactyla), identifying novel full-length endogenous retroviruses, designated as Manis pentadactyla ERVs (MPERVs). MPERVs span three retroviral genera: Alpha-, Beta-, and Gamma-retroviruses. Using genomic screening and phylogenetic analysis, we classified MPERVs and reconstructed their evolutionary history, uncovering evidence of complex recombination events and cross-species transmission. Estimated insertion times for MPERVs range from very recent to 18.38 million years ago. MPERVs exhibit diverse structural features, notably including conserved retroviral domains and functional motifs and highlighting their preservation across extensive evolutionary periods. These findings shed light on the evolutionary dynamics of ERVs in Chinese pangolin and suggest the potential for expanded host ranges among certain retrovirus genera.IMPORTANCEEndogenous retroviruses are unique viruses distinguished by the fact that they are retained as part of the host genome after an exogenous retrovirus infects the host. The Chinese pangolin, as a host with a long independent evolutionary history, likely holds valuable insights in its genome regarding retrovirus endogenization and transmission. In this study, we identified the footprints of exogenous retroviruses from three different genera in the pangolin genome: Alpharetrovirus, Betaretrovirus, and Gammaretrovirus. Additionally, by calculating the integration times of the pangolin's endogenous retroviruses and analyzing the domains of the three main functional proteins (GAG, POL, and ENV), we found that the insertions are relatively young. This suggests that these endogenous retroviruses infected the Chinese pangolin long before their endogenization. This study represents the exploration of endogenous retroviruses in the Chinese pangolin genome, expanding our understanding of endogenous retroviruses in mammals. Furthermore, our findings provide new evidence for the phenomenon of the cross-species transmission of retroviruses prior to endogenization.

Endogenous Retroviruses↗
PubMed1979

Splicing as a requirement for biogenesis of functional 16S mRNA of simian virus 40.

Simian virus 40 deletion mutants were constructed lacking specifically the intervening sequences for a late viral mRNA. The construction method involved the replacement of portions of the late simian virus 40 genes with the DNA segment from reverse transcription of the viral mRNAs. Restriction endonuclease cleavage and sequence analysis confirmed the precise structure of the mutant DNAs and demonstrated that they contained the genetic information for VP1, including all potential 5' ends for the late viral RNAs. Thus, the primary late transcription product(s) of this mutant should have the structure of functional 16S mRNAs. Complementation analysis as well as immunoprecipitation showed, however, that deletion of the intervening sequences from this mutant prevented the expression of VP1. The nature of this failure appears to be a defect in the posttranscriptional processing of the viral RNA. These results indicate that splicing is an essential function in the biogenesis of certain mRNAs.

Animals↗
PubMed2025

Phylogenetic and Genetic Evolution Analysis of Complete SFTSV Genome Sequences in Shandong Province, China.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by SFTS virus (SFTSV). Shandong province is one of the epidemic regions with high incidence rate of SFTS. To investigate phylogenetical and genetic evolution characteristics of SFTSV in Shandong province, we isolated SFTSV from suspected patients between April 2023 and October 2024, and then whole SFTSV genomes were amplified and sequenced in this study. A total of 25 new strains were analyzed together 56 strains submitted in Genbank from Shandong province. Phylogenetical and genetic analyses of the data set revealed that four genotypes were co-circulating in Shandong province. C3 genotype was the most common genotype in each year with lower genetic divergence. 298 amino acid substitutions were detected in the four proteins of SFTSV, but only two substitutions (Arg624Lys and Arg962Ser) had been proven to have potential impacts on biological functions. In addition, one reassortment strain (C3/C4/C4 for L, M and S segments) and three recombinant strains were identified. Analysis of selection pressure at the level of amino acid substitutions indicated genes within the four ORFs of SFTSV were all subjected to negative selection. In conclusion, the genetic characteristics and evolutionary mechanism of SFTSV was complex in Shandong province. It is necessary to conduct continuous surveillance to grasp the genetic evolution patterns, and to discover novel prevalent variants in a timely manner.

China↗
PubMed2025

Distinct Evolutionary Signatures of Human Parainfluenza Viruses 2 and 4 Reveal Host Antagonism Divergence and Phylogenetic Discordance.

Human parainfluenza virus 2 (HPIV-2) and human parainfluenza virus 4 (HPIV-4) are significant but underappreciated respiratory pathogens, particularly among high-risk populations including children, the elderly, and immunocompromised individuals. In this study, we sequenced 101 HPIV-2 and HPIV-4 genomes from respiratory samples collected in western Washington State and performed comprehensive evolutionary analyses using both new and publicly available sequences. Phylogenetic and phylodynamic analyses revealed that both HPIV-2 and HPIV-4 evolve at significantly faster rates compared to the mumps virus, a reference human orthorubulavirus. Notably, while HPIV-2 demonstrated the highest evolutionary rates in the surface glycoprotein HN, consistent with humoral immune-driven selection, the innate immune antagonist V/P gene evolved fastest in HPIV-4. We identified a hypervariable region within the HPIV-4V/P protein (residues 35 to 75), which structural modeling placed in a loop overlapping a known interferon antagonism domain in other paramyxovirus V proteins, though HPIV-4 is functionally incompetent in this activity. Expanded phylogenetic analysis across the Paramyxoviridae family uncovered a striking evolutionary discordance: while the HN glycoprotein and L polymerase of HPIV-4 and its 2 closest bat-derived viruses clustered within the Orthorubulavirus genus, their nucleoprotein (N), phosphoprotein (P), matrix (M), and fusion (F) proteins formed a distinct lineage outside the Rubulavirinae subfamily. Together, these findings highlight the distinct evolutionary trajectories of HPIV-2 and HPIV-4, raise hypotheses around complex Paramyxoviridae zoonotic events including recombination-like patterns, and demonstrate limitations of current L protein-based taxonomic classification schemes.

Humans↗
PubMed2026

Efficacy of NAs in combination with Peg-IFN for functional cure in patients with CHB: a meta-analysis of RCTs.

BACKGROUND: The goal of treating chronic hepatitis B (CHB) is to achieve functional cure. We aimed to evaluate the efficacy of the combination of nucleoside (acid) analogues (NAs) and pegylated interferon (Peg-IFN) on the functional cure of CHB patients at the EOT and at the EOF. METHOD: PubMed, Embase, and Web of Science were searched systematically up to March 15, 2025. Sixteen RCTs on CHB patients receiving combination or monotherapy were included. RESULT: Compared with NAs treatment, the NAs combined with Peg-IFN treatment group significantly improved HBsAg clearance rate (RR: 14.05, 95% CI 6.13-32.20) and HBsAg seroconversion rate (RR: 12.82, 95% CI 5.08-32.33) at the EOT. Moreover, compared with NAs treatment, the NAs combined with Peg-IFN treatment group significantly improved HBsAg clearance rate (RR: 7.70, 95% CI 4.24-13.98), HBsAg seroconversion rate (RR: 11.93, 95% CI 5.14-27.67) at the EOF. However, compared with Peg-IFN monotherapy, the combination therapy group did not show any improvement in HBsAg clearance rate, HBsAg seroconversion rate, and the rate of qHBsAg decrease > 1 log10 IU/mL at the EOT and the EOF. Moreover, in terms of safety, the Peg-IFN monotherapy group showed more ALT flares (ALT > 5 × ULN) during the treatment process. CONCLUSION: Compared with NAs therapy, Peg-IFN combined with NAs therapy significantly improves functional cure rate. However, combination therapy shows no additional advantage over Peg-IFN monotherapy in achieving functional cure. The Peg-IFN monotherapy group has a higher incidence of ALT flares than the combination therapy group.

Humans↗
PubMed1978

Physical mapping of herpes simplex virus-induced polypeptides.

Analysis of the polypeptides induced by 29 herpes simplex virus type 1/type 2 intertypic recombinants and correlation of the data with the crossover points in the recombinant DNAs have enabled the map positions of many polypeptides to be deduced. These include 25 polypeptides which label with [35S]methionine, 11 which label with [32P]orthophosphate, and 4 which label with [14C]glucosamine. Together with the data of Preston et al. (J. Virol., in press) on the mapping of five immediate-early polypeptides, the results show that representatives of four groups of proteins--immediate-early, late, phosphorylated, and glycosylated--map in both long and short regions. The functional organization of the herpes simplex virus genome does not therefore restrict any of these four groups to either the long or the short region.

Cell Line↗
PubMed2026

Identification and functional characterization of a novel antiviral chicken interferon-υ.

Interferons are critical mediators of antiviral immunity in vertebrates. While type IV interferon (IFN-υ) has been identified in fish and amphibians, its existence and function in chickens remained unknown. Through systematic genomic screening, we identified and cloned a novel chicken interferon gene, designated ChIFN-υ. Phylogenetic analysis placed ChIFN-υ within a distinct clade alongside zebrafish and clawed frog IFN-υ, confirming its identity as a type IV interferon, with minimal homology to classical type I, II, or III IFNs. Expression profiling revealed constitutive ChIFN-υ expression in mucosal and immune tissues of healthy chickens, exhibiting a distinct developmental shift: highest in trachea and small intestine in 1-day-old chicks, shifting to spleen and lung in 4-week-old chickens. ChIFN-υ expression was strongly upregulated following H9N2 AIV infection. Functionally, recombinant ChIFN-υ protein activated the interferon-stimulated response element (ISRE) and Mx promoter in a dose-dependent manner and significantly inhibited the replication of both vesicular stomatitis virus (VSV) and H9N2 AIV in DF-1 cells. In vivo, early treatment with exogenous ChIFN-υ significantly reduced pulmonary and tracheal viral loads and decreased oropharyngeal and cloacal virus shedding in H9N2-infected chickens. In conclusion, this study identifies and functionally characterizes the type IV interferon in chickens, elucidating the evolutionary status, regulated expression, and antiviral efficacy of ChIFN-υ. These findings highlight its potential as a candidate for developing interferon-based therapies against avian viral diseases.

Animals↗
PubMed2025

PathoSeq-QC: a decision support bioinformatics workflow for robust genomic surveillance.

MOTIVATION: Recommendations on the use of genomics for pathogens surveillance are evidence that high-throughput genomic sequencing plays a key role to fight global health threats. Coupled with bioinformatics and other data types (e.g., epidemiological information), genomics is used to obtain knowledge on health pathogenic threats and insights on their evolution, to monitor pathogens spread, and to evaluate the effectiveness of countermeasures. From a decision-making policy perspective, it is essential to ensure the entire process's quality before relying on analysis results as evidence. Available workflows usually offer quality assessment tools that are primarily focused on the quality of raw NGS reads but often struggle to keep pace with new technologies and threats, and fail to provide a robust consensus on results, necessitating manual evaluation of multiple tool outputs. RESULTS: We present PathoSeq-QC, a bioinformatics decision support workflow developed to improve the trustworthiness of genomic surveillance analyses and conclusions. Designed for SARS-CoV-2, it is suitable for any viral threat. In the specific case of SARS-CoV-2, PathoSeq-QC: (i) evaluates the quality of the raw data; (ii) assesses whether the analysed sample is composed by single or multiple lineages; (iii) produces robust variant calling results via multi-tool comparison; (iv) reports whether the produced data are in support of a recombinant virus, a novel or an already known lineage. The tool is modular, which will allow easy functionalities extension. AVAILABILITY AND IMPLEMENTATION: PathoSeq-QC is a command-line tool written in Python and R. The code is available at https://code.europa.eu/dighealth/pathoseq-qc.

Genomics↗
PubMed2012

MRI roadmap-guided transendocardial delivery of exon-skipping recombinant adeno-associated virus restores dystrophin expression in a canine model of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) cardiomyopathy patients currently have no therapeutic options. We evaluated catheter-based transendocardial delivery of a recombinant adeno-associated virus (rAAV) expressing a small nuclear U7 RNA (U7smOPT) complementary to specific cis-acting splicing signals. Eliminating specific exons restores the open reading frame resulting in translation of truncated dystrophin protein. To test this approach in a clinically relevant DMD model, golden retriever muscular dystrophy (GRMD) dogs received serotype 6 rAAV-U7smOPT via the intracoronary or transendocardial route. Transendocardial injections were administered with an injection-tipped catheter and fluoroscopic guidance using X-ray fused with magnetic resonance imaging (XFM) roadmaps. Three months after treatment, tissues were analyzed for DNA, RNA, dystrophin protein, and histology. Whereas intracoronary delivery did not result in effective transduction, transendocardial injections, XFM guidance, enabled 30&#xb1;10 non-overlapping injections per animal. Vector DNA was detectable in all samples tested and ranged from <1 to >3000 vector genome copies per cell. RNA analysis, western blot analysis, and immunohistology demonstrated extensive expression of skipped RNA and dystrophin protein in the treated myocardium. Left ventricular function remained unchanged over a 3-month follow-up. These results demonstrated that effective transendocardial delivery of rAAV-U7smOPT was achieved using XFM. This approach restores an open reading frame for dystrophin in affected dogs and has potential clinical utility.

Animals↗
PubMed2026

Heat shock protein 40 enhances axon regeneration in a mouse model of traumatic optic neuropathy.

Retinal ganglion cell death occurs following injury to the optic nerve either by trauma or in disease such as glaucoma, leading to severe vision loss. Recent innovations have demonstrated that optic nerve regeneration is feasible; however, the regeneration is limited. The aim of the present study is to identify genomic elements enhancing axon regeneration. We have taken a forward genetics approach using the BXD recombinant mouse strains to identify a gene that increases the extent of optic nerve regeneration. Axon regeneration was induced by knocking down Pten in retinal ganglion cells using adeno-associated virus to deliver an shRNA followed by an intravitreal injection of Zymosan with CPT-cAMP that produced a mild inflammatory response. Retinal ganglion cell axons were damaged by optic nerve crush. Following a 12-day survival period, regenerating axons were labeled by intravitreal injection of Cholera Toxin B conjugated with Alexa Fluor 647. Two days later, labeled axons within the optic nerve were examined to determine the number of regenerating axons and the distance they traveled down the optic nerve. The analysis revealed a surprising difference in the amount of axonal regeneration across all 33 BXD strains. There was a 7.5-fold difference in the number of regenerating axons and a 4-fold difference in the distance traveled by regenerating axons. These data were used to generate an interval map defining genomic loci that modulate enhanced axonal regeneration. A quantitative trait locus modulating axon regeneration was identified on Chromosome 14 (115 to 119 Mb). Within this locus were 16 annotated genes. Subsequent testing revealed that one candidate gene, Dnajc3, modulated axonal regeneration. Dnajc3 encodes heat shock protein 40 (HSP40), a molecular chaperone. Knocking down Dnajc3 in the high regenerative strain (BXD90) led to a decreased regeneration response, whereas, overexpression of Dnajc3 in a low regenerative strain (BXD34) resulted in an increased regeneration response. These findings reveal that Dnajc3 not only increases the number of regenerating axons, but also increases the distance that axons travel. The enhanced regeneration will prove to be critical for functional recovery in humans, where the distance axons travel to their targets is considerably longer than that of mice.

axon regeneration↗