Nuclear Phosphoprotein Research Articles

Efficacy of agomelatine on sleep disorders and lateral habenula neuronal activity in chronic restraint stress depression model mice.

Sleep disorders (SD) are one of the common manifestations of depression patients. This article aimed to explore the effect of Agomelatine (Ago) on SD in chronic restraint stress (CRS) depression model mice and its effect on the activity of neurons in the lateral habenula (LHb). 30 C57BL/6J mice were divided into normal (C57BL/6J) group, CRS group, and Ago group. CRS experiment was used to establish the depression model, and Ago was used to treat CRS mice. Based on behavioral tests in mice and electrophysiology record, SD and LHb neuron activity were assessed. The expression levels of brain-derived neurotrophic factor (BDNF) and nuclear phosphoprotein (c-Fos) in LHb were detected by Western blot (WB). As against the CRS group, the Ago group had a reduction in the immobility time during forced swimming training and an increase in the preference for sucrose in the sucrose preference test; The expression levels of c-Fos and BDNF proteins in the LHb neurons of the Ago group mice were lower than those in the CRS group (P < 0.05), and the values approached the levels of the normal control group. In both dark and light environments, the rapid eye movement (REM) sleep duration of the CRS group mice was significantly longer than that of the normal control group (P < 0.05). It was concluded that Ago may intervene in the depressive-like behavior and overall sleep patterns of CRS depression model mice by regulating the activity of LHb neurons and inhibiting the neuroinflammatory process. This provides a potential drug target for the development of new treatment strategies for depression.

Clinical Impact of C-myc Oncogenic Diversity on Solid and Lymphoid Malignancies.

Onset and progression of malignant tumors is a multistep process including a variety of gross chromosomal and specific genes' deregulation. Among oncogenes that are frequently altered in solid and also in hematological malignancies, the C-myc (gene locus: 8q24.21) plays a pivotal role. C-myc is a proto-oncogene encoding for a nuclear phosphoprotein implicated in cell cycle progression, apoptosis and cellular differentiation and transformation. The purpose of the current molecular review was to explore the differences of C-myc oncogenic activity in solid and lymphoid malignancies that modify its clinical impact on them. A systematic review of the literature in the international database PubMed was carried out. The year 2010 was set as a prominent time limit for the publication date of articles in the majority of them, whereas specific references of great importance and historical value in the field of C-myc gene discovery and analysis were also included. The following keywords were used: C-myc, oncogene, signaling pathway, malignancies, carcinoma, lymphoma. A pool of 43 important articles were selected for the present study at the basis of combining molecular knowledge with new targeted therapeutic strategies. C-myc oncogene demonstrates two different mechanisms of deregulation: amplification, mutation and translocation patterns. These particular aspects of gene alteration are unique for solid and non-solid (hematological) malignancies, respectively. C-myc is characterized by diversity regarding its deregulation mechanisms in malignancies derived from different tissues. C-myc translocation is sporadically combined with amplification ("complicon" formation) or mutations creating exotic genetic signatures. This "bi-phasic" C-myc deregulation model in the corresponding malignant tumor categories clinically affects the corresponding patients, also modifying the targeted therapeutic strategies on them.

Structures of H5N1 influenza polymerase with ANP32B reveal mechanisms of genome replication and host adaptation

Avian influenza A viruses (IAVs) pose a public health threat, as they are capable of triggering pandemics by crossing species barriers. Replication of avian IAVs in mammalian cells is hindered by species-specific variation in acidic nuclear phosphoprotein 32 (ANP32) proteins, which are essential for viral RNA genome replication. Adaptive mutations enable the IAV RNA polymerase (FluPolA) to surmount this barrier. Here, we present cryo-electron microscopy structures of monomeric and dimeric avian H5N1 FluPolA with human ANP32B. ANP32B interacts with the PA subunit of FluPolA in the monomeric form, at the site used for its docking onto the C-terminal domain of host RNA polymerase II during viral transcription. ANP32B acts as a chaperone, guiding FluPolA towards a ribonucleoprotein-associated FluPolA to form an asymmetric dimer—the replication platform for the viral genome. These findings offer insights into the molecular mechanisms governing IAV genome replication, while enhancing our understanding of the molecular processes underpinning mammalian adaptations in avian-origin FluPolA.

Mechanism of Chaijin Jieyu Anshen Tablets in regulating abnormal ACC-vHPC glutaminergic neural circuit to alleviate synaptic remodeling of ventral hippocampal neurons in depressed rats

This study aims to reveal the molecular mechanism of Chaijin Jieyu Anshen Tablets(CJJYAS) in regulating the abnormal anterior cingulate cortex(ACC)-ventral hippocampus(vHPC) glutaminergic neural circuit to alleviate synaptic remodeling of ventral hippocampal neurons in depressed rats. Firstly, the study used chemogenetics to localize glutaminergic adeno-associated virus(AAV) into the ACC brain region of rats. The model of depressed rats was established by chronic unpredictable mild stress(CUMS) combined with independent feeding. The rats were randomly divided into control group, model group, AAV empty group, AAV group, AAV+ glucocorticoid receptors(GR) blocker group, AAV+chemokine receptor 1(CX3CR1) blocker group, and AAV+CJJYAS group. Depressive-like behaviors of rats were evaluated by open-field, forced-swimming, and Morris water maze tests, combined with an animal behavior analysis system. The morphological and structural changes of ACC and vHPC neurons in rats were observed by hematoxylin-eosin(HE) staining. Immunofluorescence and nuclear phosphoprotein(c-Fos) were used to detect glutaminergic neural circuit activation of ACC-vHPC in rats. The changes in dendrites, synaptic spines, and synaptic submicrostructure of vHPC neurons were observed by Golgi staining and transmission electron microscopy, respectively. The expressions of synaptic remodeling-related proteins N-methyl-D-asprtate receptor 2A(GRIN2A), N-methyl-D-asprtate receptor 2B(GRIN2B), Ca~(2+)/calmodulin-dependent protein kinase Ⅱ(CaMKⅡ), mitogen-activated protein kinase-activated protein kinase 2(MK2), and a ubiquitous actin-binding protein(cofilin) in vHPC glutaminergic neurons of rats were detected by immunofluorescence and Western blot, respectively. The results indicated that the activated glutaminergic AAV aggravated the depressive-like behaviors phenotype of rats in the model group and deteriorated the damage of morphology and structure of ACC and vHPC neurons and synaptic ultrastructure. However, both GR and CX3CR1 bloc-kers could reverse the abnormal changes to varying degrees, suggesting that the abnormal activation of ACC-vHPC glutaminergic neural circuit mediated by GR/CX3CR1 signals in gliocytes in the ACC brain region may be closely related to the occurrence and development of depression. Interestingly, CJJYAS significantly inhibited the activation of the ACC-vHPC glutaminergic neural circuit induced by AAV and the elevated Glu level. Furthermore, CJJYAS could also effectively reverse the aggravation of depressive-like behaviors and synaptic remodeling of vHPC neurons of rats in the model group induced by the activated AAV. Additionally, the findings suggested that the molecular mechanism of CJJYAS in improving synaptic damage of vHPC neurons might be related to the regulation of synaptic remodeling-related signals such as NR/CaMKⅡ and MK2/cofilin. In conclusion, this research confirms that CJJYAS effectively regulates the abnormal ACC-vHPC glutaminergic neural circuit and alleviates the synaptic remodeling of vHPC glutaminergic neurons in depressed rats, and the molecular mechanism might be associated with the regulation of synapse-related NR/CaMKⅡ and MK2/cofilin signaling pathways, which may be the crucial mechanism of its antidepressant effect.

Knockdown of ANP32E inhibits colorectal cancer cell growth and glycolysis by regulating the AKT/mTOR pathway.

Colorectal cancer (CRC) is the third most common tumor, with an increasing number of deaths worldwide each year. Tremendous advances in the diagnosis and treatment of CRC have significantly improved the outcomes for CRC patients. Additionally, accumulating evidence has hinted the relationship between acidic nuclear phosphoprotein 32 family member E (ANP32E) and cancer progression. But the role of ANP32E in CRC remains unclear. In our study, through TCGA database, it was demonstrated that the expression of ANP32E was enhanced in COAD tissues (n = 286). In addition, the mRNA and protein expression of ANP32E was also confirmed to be upregulated in CRC cell lines. Further investigation uncovered that knockdown of ANP32E suppressed cell proliferation and glycolysis, and facilitated cell apoptosis in CRC. Moreover, inhibition of ANP32E inhibited the AKT/mTOR pathway. Through rescue assays, we discovered that the reduced cell proliferation, glycolysis and the enhanced cell apoptosis mediated by ANP32E repression was reversed by SC79 treatment. In summary, ANP32E aggravated the growth and glycolysis of CRC cells by stimulating the AKT/mTOR pathway. This finding suggested that the ANP32E has the potential to be explored as a novel biomarker for CRC treatment.

GSK3β phosphorylates Six1 transcription factor and regulates its APC/CCdh1 mediated proteosomal degradation

Sine oculis homeobox homolog 1 (Six1) is a developmentally important transcription factor that regulates cellular proliferation, apoptosis, and dissemination during embryogenesis. Six1 overexpression as reported in multiple cancers modulates expression of a repertoire of its target genes causing an increase in proliferation, metastasis and survival of cancer cells. Six1 exists as a cell cycle regulated nuclear phosphoprotein and its cellular turnover is regulated by APC/C (Anaphase promoting complex / Cyclosome) complex mediated proteolysis. However, the kinases that regulate Six1 proteolysis have not been identified and the mechanistic details that cause its overproduction in various cancers are lacking. Here, we report that Six1 is a physiological GSK3β substrate. GSK3β interacts with Six1 and phosphorylates it at Ser221 within the conserved consensus sequence in its carboxy terminus. Using pharmacological inhibition, siRNA mediated knockdown and protein overexpression of GSK3β; we show that GSK3β regulates Six1 protein stability. Pulse chase analysis of Six1 revealed that GSK3β regulates its ubiquitin proteolysis such that Six1 phosphomimicking mutant (Six1S221E) for Ser221 site had dramatically increased half-life than its phosphodeficient (Six1S221A) and wild type variants. Furthermore, we demonstrate that GSK3β rescues Six1 from APC dependent proteolysis by regulating its binding with APC/C co-activator protein Cdh1. Importantly, strong positive correlation exists between GSK3β and Six1 protein levels throughout the cell cycle and in multiple cancers indicating that GSK3β activation may in part contribute to Six1 overproduction in a subset of human cancers.

The host RNA polymerase II C-terminal domain is the anchor for replication of the influenza virus genome.

The current model is that the influenza virus polymerase (FluPol) binds either to host RNA polymerase II (RNAP II) or to the acidic nuclear phosphoprotein 32 (ANP32), which drives its conformation and activity towards transcription or replication of the viral genome, respectively. Here, we provide evidence that the FluPol-RNAP II binding interface, beyond its well-acknowledged function in cap-snatching during transcription initiation, has also a pivotal role in replication of the viral genome. Using a combination of cell-based and in vitro approaches, we show that the RNAP II C-terminal-domain, jointly with ANP32, enhances FluPol replication activity. We observe successive conformational changes to switch from a transcriptase to a replicase conformation in the presence of the bound RNPAII C-terminal domain and propose a model in which the host RNAP II is the anchor for transcription and replication of the viral genome. Our data open new perspectives on the spatial coupling of viral transcription and replication and the coordinated balance between these two activities.

Avian ANP32A incorporated in avian influenza A virions promotes interspecies transmission by priming early viral replication in mammals.

Species-specific differences in acidic nuclear phosphoprotein 32 family member A (ANP32A) determine the restriction of avian-signature polymerase in mammalian cells. Mutations that evade this restriction, such as PB2-E627K, are frequently acquired when avian influenza A viruses jump from avian hosts to mammalian hosts. However, the mechanism underlying this adaptation process is still unclear. Here, we report that host factor ANP32 proteins can be incorporated into influenza viral particles through combination with the viral RNA polymerase (vPol) and then transferred into targeted cells where they support virus replication. The packaging of the ANP32 proteins into influenza viruses is dependent on their affinity with the vPol. Avian ANP32A (avANP32A) delivered by avian influenza A virions primes early viral replication in mammalian cells, thereby favoring the downstream interspecies transmission event by increasing the total amount of virus carrying adaptive mutations. Our study clarifies one role of avANP32A where it is used by avian influenza virus to help counteract the restriction barrier in mammals.

Abstract B042: A screen to identify modifiers of BRCA1 protein level for cancer prevention and treatment

Abstract The breast cancer susceptibility gene 1 (BRCA1) is a nuclear phosphoprotein involved in DNA double-strand break (DSB) repair and maintenance of genome stability. A single BRCA1 mutation leads to reduced levels of functional BRCA1 protein, such that DSB repair is compromised. It has been proposed that BRCA1 is a haploinsufficient tumor suppressor gene in some contexts, which when lost accelerates the mutation rate of other critical genes thus increasing neoplastic transformation. BRCA1 expression levels are modified through exogenous exposures, and modulating BRCA1 expression may alter tumour onset, progression, and treatment options. We hypothesize that compounds that increase BRCA1 expression and function may prevent the outgrowth of BRCA1-associated breast cancer. By contrast, compounds that reduce BRCA1 protein level could be used as combination therapries in conjunction with poly-ADP ribose polymerase (PARP) inhibitors. To achieve these goals, we generated BRCA1-reporter cell lines. Using CRISPR-assisted genome editing, we endogenously tagged the BRCA1 protein with HiBiT, an 11 amino acid luminescent tag. BRCA1-targeting was verified by sequencing and immunoblotting, and functional validation was performed with known modulators of BRCA1 expression. Our tests confirmed that HiBiT-tagging allows for sensitive measurement of BRCA1 protein levels, therefore permitting screenability. BRCA1-reporter cells were subsequently used to conduct a pilot screen (64 epigenetic-modifying drugs) and a high-content screen (6,000 compounds). We identified several compounds that modified BRCA1 protein expression (B-score &amp;gt;3*SD). The epigenetic drug library yielded five repressors and two activators, and the high-content screen identified 163 repressors and 12 activators. Validation studies have confirmed that the activator drug, aloxistatin can elevate BRCA1-HiBiT levels in a dose-dependent manner. Additionally, aloxistatin treatment increased BRCA1 expression and function in a panel of breast cells. We have also assessed 9 down-regulators of BRCA1 from the pilot and high-content screens. Each of these nine compounds reduced the expression of BRCA1 protein and synergized with the PARP inhibitor olaparib to inhibit cancer cell growth. Collectively, our ongoing studies suggest that BRCA1 activation may reduce cancer phenotypes and BRCA1 repression can sensitize breast cancer cells to PARP-inhibition and other chemotherapies. Overall, using our reporter cell lines we have identified a number of unique compounds that effectively modify BRCA1 expression and function that may have utility in the treatment and prevention of BRCA1-associated cancers. Citation Format: Erin Sellars, Margarita Savguira, Joanne Kotsopoulos, Leonardo Salmena. A screen to identify modifiers of BRCA1 protein level for cancer prevention and treatment [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr B042.

ANP32B promotes colorectal cancer cell progression and reduces cell sensitivity to PRAP1 inhibitor through up-regulating HPF1

ANP32B, a member of the acidic leucine-rich nuclear phosphoprotein 32 family member B, is aberrantly expressed in various cancers, including colorectal cancer. However, the function and mechanism of action of ANP32B in colorectal cancer remain unclear. The present study therefore analyzed the expression of ANP32B and its activity in colorectal cancer patient samples and colorectal cancer cell lines. ANP32B expression was found to be significantly upregulated in colorectal cancer patient samples and cell lines. Upregulation of ANP32B enhanced colorectal cancer cell proliferation and migration, whereas downregulation of ANP32B suppressed colorectal cancer cell proliferation. RNA sequencing analysis of differentially expressed genes in ANP32B silenced colorectal cancer cells showed that histone PARylation factor 1 (HPF1), which protects against DNA damage by interacting with the anti-tumor target PARP1, was significantly downregulated. Luciferase promoter assays testing the regulatory association between ANP32B and HPF1 showed that ANP32B interacted with the HPF1 promoter. Analysis of colorectal cancer samples from The Cancer Genome Atlas showed that ANP32B and HPF1 expression were positively correlated, and recovery assays showed that ANP32B promoted colorectal cancer progression by up-regulating HPF1. Overexpression of ANP32B also reduced the sensitivity of colorectal cancer cells to PARP1 inhibitor, consistent with the oncogenic role of ANP32B. ANP32B may alter the sensitivity of colorectal cancer cells to PARP1 inhibitor via a mechanism associated with the HPF1 gene. In summary, these findings showed that ANP32B acted as a tumor promoter, potentiating both colorectal cancer malignancy and drug resistance. Targeting the ANP32B/HPF1 axis may have benefit for patients with colorectal cancer.

Role of feline ANP32 proteins in regulating polymerase activity of influenza A virus

Recently, increasing natural infection cases and experimental animal challenge studies demonstrated domestic cats are susceptible to multiple subtypes influenza A virus (IAV) infections. Notably, some subtype IAV strains could circulate in domestic cats after cross-species transmission and even infected humans, posing a threat to public health. Host factors related to viral polymerase activity could determine host range of IAV and acidic nuclear phosphoprotein 32 (ANP32) is the most important one among them. However, role of cat-derived ANP32 on viral polymerase activity and host range of IAV is still unknown. In the present study, a total of 10 feline ANP32 (feANP32) splice variants (including 5 feANP32A, 3 feANP32B, and 2 feANP32E) were obtained from domestic cats by RT-PCR. Sequence alignment results demonstrated amino acid deletions and/or insertions occurred among feANP32 variants, but all feANP32 proteins were primarily localized to cell nucleus. Minigenome replication systems for several representative IAV strains were established and the support ability of feANP32 on IAV polymerase activity was estimated. The results indicated that most feANP32A and feANP32B splice variants were able to support all the tested IAV strains, though the support activity of a single feANP32 protein on polymerase activity varied among different IAV strains. In addition, the role of feANP32 in supporting H3N2 canine influenza virus was determined by investigating viral replication in vitro. Collectively, our study systematically investigated the support activity of feANP32 on IAV, providing a clue for further exploring the mechanism of susceptibility of cats to IAV.

Comparative analysis of PB2 residue 627E/K/V in H5 subtypes of avian influenza viruses isolated from birds and mammals.

Avian influenza viruses (AIVs) are naturally found in wild birds, primarily in migratory waterfowl. Although species barriers exist, many AIVs have demonstrated the ability to jump from bird species to mammalian species. A key contributor to this jump is the adaption of the viral RNA polymerase complex to a new host for efficient replication of its RNA genome. The AIV PB2 gene appears to be essential in this conversion, as key residues have been discovered at amino acid position 627 that interact with the host cellular protein, acidic nuclear phosphoprotein 32 family member A (ANP32A). In particular, the conversion of glutamic acid (E) to lysine (K) is frequently observed at this position following isolation in mammals. The focus of this report was to compare the distribution of PB2 627 residues from different lineages and origins of H5 AIV, determine the prevalence between historical and contemporary sequences, and investigate the ratio of amino acids in avian vs. mammalian AIV sequences. Results demonstrate a low prevalence of E627K in H5 non-Goose/Guangdong/1996-lineage (Gs/GD) AIV samples, with a low number of mammalian sequences in general. In contrast, the H5-Gs/GD lineage sequences had an increased prevalence of the E627K mutation and contained more mammalian sequences. An approximate 40% conversion of E to K was observed in human sequences of H5 AIV, suggesting a non-exclusive requirement. Taken together, these results expand our understanding of the distribution of these residues within different subtypes of AIV and aid in our knowledge of PB2 mutations in different species.

Glaucoma-Associated CDR1 Peptide Promotes RGC Survival in Retinal Explants through Molecular Interaction with Acidic Leucine Rich Nuclear Phosphoprotein 32A (ANP32A).

Glaucoma is a complex, multifactorial optic neuropathy mainly characterized by the progressive loss of retinal ganglion cells (RGCs) and their axons, resulting in a decline of visual function. The pathogenic molecular mechanism of glaucoma is still not well understood, and therapeutic strategies specifically addressing the neurodegenerative component of this ocular disease are urgently needed. Novel immunotherapeutics might overcome this problem by targeting specific molecular structures in the retina and providing direct neuroprotection via different modes of action. Within the scope of this research, the present study showed for the first time beneficial effects of the synthetic CDR1 peptide SCTGTSSDVGGYNYVSWYQ on the viability of RGCs ex vivo in a concentration-dependent manner compared to untreated control explants (CTRL, 50 µg/mL: p < 0.05 and 100 µg/mL: p < 0.001). Thereby, this specific peptide was identified first as a potential biomarker candidate in the serum of glaucoma patients and was significantly lower expressed in systemic IgG molecules compared to healthy control subjects. Furthermore, MS-based co-immunoprecipitation experiments confirmed the specific interaction of synthetic CDR1 with retinal acidic leucine-rich nuclear phosphoprotein 32A (ANP32A; p < 0.001 and log2 fold change > 3), which is a highly expressed protein in neurological tissues with multifactorial biological functions. In silico binding prediction analysis revealed the N-terminal leucine-rich repeat (LRR) domain of ANP32A as a significant binding site for synthetic CDR1, which was previously reported as an important docking site for protein-protein interactions (PPI). In accordance with these findings, quantitative proteomic analysis of the retinae ± CDR1 treatment resulted in the identification of 25 protein markers, which were significantly differentially distributed between both experimental groups (CTRL and CDR1, p < 0.05). Particularly, acetyl-CoA biosynthesis I-related enzymes (e.g., DLAT and PDHA1), as well as cytoskeleton-regulating proteins (e.g., MSN), were highly expressed by synthetic CDR1 treatment in the retina; on the contrary, direct ANP32A-interacting proteins (e.g., NME1 and PPP2R4), as well as neurodegenerative-related markers (e.g., CEND1), were identified with significant lower abundancy in the CDR1-treated retinae compared to CTRL. Furthermore, retinal protein phosphorylation and histone acetylation were also affected by synthetic CDR1, which are both partially controlled by ANP32A. In conclusion, the synthetic CDR1 peptide provides a great translational potential for the treatment of glaucoma in the future by eliciting its neuroprotective mechanism via specific interaction with ANP32A's N terminal LRR domain.

ANP32B suppresses B-cell acute lymphoblastic leukemia through activation of PU.1 in mice.

ANP32B, a member of the acidic leucine-rich nuclear phosphoprotein 32 kDa (ANP32) family of proteins, is critical for normal development because its constitutive knockout mice are perinatal lethal. It is also shown that ANP32B acts as a tumor-promoting gene in some kinds of cancer such as breast cancer and chronic myelogenous leukemia. Herein, we observe that ANP32B is lowly expressed in B-cell acute lymphoblastic leukemia (B-ALL) patients, which correlates with poor prognosis. Furthermore, we utilized the N-myc or BCR-ABLp190 -induced B-ALL mouse model to investigate the role of ANP32B in B-ALL development. Intriguingly, conditional deletion of Anp32b in hematopoietic cells significantly promotes leukemogenesis in two B-ALL mouse models. Mechanistically, ANP32B interacts with purine rich box-1 (PU.1) and enhances the transcriptional activity of PU.1 in B-ALL cells. Overexpression of PU.1 dramatically suppresses B-ALL progression, and highly expressed PU.1 significantly reverses the accelerated leukemogenesis in Anp32b-deficient mice. Collectively, our findings identify ANP32B as a suppressor gene and provide novel insight into B-ALL pathogenesis.

ANP32B promotes lung cancer progression by regulating VDAC1

It has been reported before that acidic leucine-rich nuclear phosphoprotein 32 family member B (ANP32B) plays roles in many cancers, yet no report of its role in lung cancer exists. In this study, we documented an elevation of ANP32B within lung cancer tissues and cells. Knockdown of ANP32B hindered the proliferation as well as migration of lung cancer cells, whereas overexpression of ANP32B helps to promote the malignant progression of lung cancer. ANP32B also regulates lung cancer cells’ apoptosis and cell cycling. In addition, voltage-dependent anion channel 1 (VDAC1) has been found to be a downstream targeted gene of ANP32B and is positively regulated by ANP32B in lung cancer cells. According to our research, the expression of VDAC1 was positively associated with ANP32B expression in lung adenocarcinoma (r = 0.61, P < 0.001) samples by Pearson’s correlation coefficient analysis. Furthermore, rescue experiments demonstrated that VDAC1 could rescue the effect of ANP32B expression on lung cancer cell proliferation and migration. Our results suggest that ANP32B overexpression facilitates lung cancer progression by increasing the expression of VDAC1. As such, we have revealed a novel mechanism regulating the connection between ANP32B and VDAC1 and a potential role of ANP32B as an oncogene and a clinical therapeutic target in lung cancer.

Anp32a Promotes Neuronal Regeneration after Spinal Cord Injury of Zebrafish Embryos.

After spinal cord injury (SCI) in mammals, neuronal regeneration is limited; in contrast, such regeneration occurs quickly in zebrafish. Member A of the acidic nuclear phosphoprotein 32 (ANP32a) family is involved in neuronal development, but its function is controversial, and its involvement in zebrafish SCI remains unknown. To determine the role of zebrafish ANP32a in the neuronal regeneration of SCI embryos, we microinjected ANP32a mRNA into embryos from zebrafish transgenic line Tg(mnx1:GFP) prior to SCI. Compared to control SCI embryos, the results showed that the regeneration of spinal cord and resumption of swimming capability were promoted by the overexpression of ANP32a mRNA but reduced by its knockdown. We next combined fluorescence-activated cell sorting with immunochemical staining of anti-GFAP and immunofluorescence staining against anti-PH3 on Tg(gfap:GFP) SCI embryos. The results showed that ANP32a promoted the proliferation and cell number of radial glial cells at the injury epicenter at 24 h post-injury (hpi). Moreover, when we applied BrdU labeling to SCI embryos derived from crossing the Tg(gfap:GFP) and Tg(mnx1:TagRFP) lines, we found that both radial glial cells and motor neurons had proliferated, along with their increased cell numbers in Anp32a-overexpression SCI-embryos. On this basis, we conclude that ANP32a plays a positive role in the regeneration of zebrafish SCI embryos.

AIMP1 promotes multiple myeloma malignancy through interacting with ANP32A to mediate histone H3 acetylation

Multiple myeloma (MM) is the second most common hematological malignancy. An overwhelming majority of patients with MM progress to serious osteolytic bone disease. Aminoacyl-tRNA synthetase-interacting multifunctional protein 1 (AIMP1) participates in several steps during cancer development and osteoclast differentiation. This study aimed to explore its role in MM. The gene expression profiling cohorts of MM were applied to determine the expression of AIMP1 and its association with MM patient prognosis. Enzyme-linked immunosorbent assay, immunohistochemistry, and Western blotting were used to detect AIMP1 expression. Protein chip analysis, RNA-sequencing, and chromatin immunoprecipitation and next-generation sequencing were employed to screen the interacting proteins and key downstream targets of AIMP1. The impact of AIMP1 on cellular proliferation was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in vitro and a xenograft model in vivo. Bone lesions were evaluated using tartrate-resistant acid phosphatase staining in vitro. A NOD/SCID-TIBIA mouse model was used to evaluate the effect of siAIMP1-loaded exosomes on bone lesion formation in vivo. AIMP1 expression was increased in MM patients and strongly associated with unfavorable outcomes. Increased AIMP1 expression promoted MM cell proliferation in vitro and in vivo via activation of the mitogen-activated protein kinase (MAPK) signaling pathway. Protein chip assays and subsequent experiments revealed that AIMP1 interacted with acidic leucine-rich nuclear phosphoprotein 32 family member A (ANP32A) to regulate histone H3 acetylation. In addition, AIMP1 increased histone H3 acetylation enrichment function of GRB2-associated and regulator of MAPK protein 2 (GAREM2) to increase the phosphorylation of extracellular-regulated kinase 1/2 (p-ERK1/2). Furthermore, AIMP1 promoted osteoclast differentiation by activating nuclear factor of activated T cells c1 (NFATc1) in vitro. In contrast, exosome-coated small interfering RNA of AIMP1 effectively suppressed MM progression and osteoclast differentiation in vitro and in vivo. Our data demonstrate that AIMP1 is a novel regulator of histone H3 acetylation interacting with ANP32A in MM, which accelerates MM malignancy via activation of the MAPK signaling pathway.

Purification of influenza C virus polymerase based on huANP32A protein and efficient preparation of monoclonal antibody targeting PB2 protein

Influenza C virus is an important respiratory pathogen not only infecting people, but also pigs, dogs, and other animals. Polymerase is central to the replication of influenza C virus and is an important target for studying the mechanism of viral replication. However, there is no commercial monoclonal antibody (MAb) targeting influenza C virus polymerase, which hampers the development of relevant research to some extent. In order to prepare MAb targeting the polymerase basic protein 2 (PB2) of influenza C virus, influenza C virus RNA-dependent RNA polymerase (RdRp, consists of PB1, PB2 and P3) was co-immunoprecipitated with Flag-tagged human acidic nuclear phosphoprotein 32A (huANP32A-Flag) from 293T cells based on the interaction between huANP32A and influenza virus RdRp. The purified RdRp was used as antigen to immunize BALB/c mice. Six positive hybridoma cell lines (7B11-5, 8A4-5, 13D9-6, 8D4-1, 8D4-3, 9F9-4) that stably secrete and recognize PB2 MAb were screened by indirect ELISA and Western blotting. The subtypes of MAb 7B11-5, 8A4-5, 8D4-1 and 8D4-3 antibody were identified as IgG1, the subtypes of MAb 13D9-6 and 9F9-4 were IgG2a and IgG3, respectively. All the light chains of the MAbs were κ chain. A hybridoma cell line 8D4-1 with high titer was further selected to prepare ascites. The titer of mouse ascites antibody was determined to be 1:64 000. Western blotting results showed that the MAb 8D4-1 had a specific immune response with ICV PB2; laser confocal assay showed that the prepared MAb 8D4-1 accurately detected the subcellular localization of PB2 subunits. Moreover, ICV RdRp was highly enriched by ANP32A. The high specific of the prepared PB2 MAb 8D4-1 may facilitate the polymerase detection, structural analysis and mechanism study of influenza C virus.

ANP32E contributes to gastric cancer progression via NUF2 upregulation.

Acidic nuclear phosphoprotein 32 family member E (ANP32E) is a histone chaperone that removes H2A.Z from chromatin. ANP32E is implicated in numerous cellular processes, including cell proliferation, apoptosis and cell differentiation. Increasing evidence suggests that dysregulation of ANP32E expression is strongly associated with carcinogenesis. However, the relationship between ANP32E in the development of gastric cancer (GC) is unknown. The present study aimed to explore the potential role of ANP32E in the development of GC using gain-of-function, loss-of-function, CCK-8, colony formation, apoptosis, reverse transcription-quantitative PCR, immunoblotting and luciferase reporter assay. The results of the present study demonstrated that ANP32E expression levels were significantly increased in GC tissues. ANP32E knockdown markedly inhibited GC cell proliferation and colony formation and significantly induced GC cell apoptosis, whereas overexpression of ANP32E significantly induced GC cell malignancy. Furthermore, the results demonstrated that there was a positive association between ANP32E and NUF2 component of NDC80 kinetochore complex (NUF2) expression levels. By assessing NUF2 expression levels, it was demonstrated that ANP32E promoted tumor cell proliferation and inhibited cell apoptosis by increasing NUF2 expression levels in GC cell lines. In conclusion, the present study indicated that ANP32E may function as an efficient oncogene, which promotes tumorigenesis of GC cells by inducing NUF2 expression.

Genome-wide CRISPR/Cas9 transcriptional activation screen identifies a histone acetyltransferase inhibitor complex as a regulator of HIV-1 integration.

The retrovirus human immunodeficiency virus-1 (HIV-1) is the causative agent of AIDS. Although treatment of HIV/AIDS with antiretroviral therapy provides suppression of viremia, latent reservoirs of integrated proviruses preclude cure by current antiviral treatments. Understanding the mechanisms of host–viral interactions may elucidate new treatment strategies. Here, we performed a CRISPR/Cas9 transcriptional activation screen using a high-complexity, genome-wide sgRNA library to identify cellular factors that inhibit HIV-1 infection of human CD4+ T cells. MT4 cells were transduced with a CRISPR/Cas9 sgRNA library and infected with nef-deficient HIV-1NL4-3 expressing ganciclovir-sensitive thymidine kinase, thus enabling selection of HIV-1-resistant cells for analysis of enriched sgRNAs. After validation of screen hits, multiple host factors essential for HIV-1 infection were identified, including SET (SET nuclear proto-oncogene) and ANP32A (acidic nuclear phosphoprotein 32A, PP32A), which together form a histone acetylase inhibitor complex. Using multiple human cell lines and peripheral blood mononuclear cells (PBMCs) from healthy donors and HIV-1-infected individuals, we demonstrate that SET depletion increased HIV-1 infectivity by augmenting DNA integration without significantly changing sites of integration. Conversely, SET overexpression decreased HIV-1 integration and infectivity. SET protein expression was significantly reduced in PBMCs from HIV-1-infected individuals and was downregulated by HIV-1 infection of healthy donor cells in vitro. Notably, HIV-1-induced downregulation of SET could be alleviated by inhibition of the protease granzyme A. Altogether, we have identified cellular inhibitors of HIV-1 infection on a genome-wide scale, which affords new insight into host–virus interactions and may provide new strategies for HIV-1 treatment.