Ghrelin alleviates placental dysfunction by down-regulating NF-κB phosphorylation in LPS-induced rat model of preeclampsia.

In our previous study, we uncovered that ghrelin promotes angiogenesis in human umbilical vein endothelial cells (HUVECs) in vitro by activating the Jagged1/Notch2/VEGF pathway in preeclampsia (PE). However, the regulatory effects of ghrelin on placental dysfunction in PE are unclear. Therefore, we applied Normal pregnant Sprague-Dawley (SD) rats, treated with lipopolysaccharide (LPS), to establish a PE-like rat model. The hematoxylin-eosin (HE) staining method and immunohistochemistry (IHC) technology were used to detect morphological features of the placenta. IHC and Western blot were applied to examine Bax and Bcl-2 expression levels. The concentrations of serum soluble fms-like tyrosine kinase-1 (sFlt1) and placental growth factor (PIGF) were assessed by enzyme-linked immunosorbent assay (ELISA) kit. In addition, the apoptosis rates of JEG-3 and HTR-8/SVneo trophoblast cells were determined by Annexin V-FITC/PI apoptosis detection kit. Cell migratory capacities were assessed by scratch-wound assay, and RNA-sequencing assay was used to determine the mechanism of ghrelin in regulating trophoblast apoptosis. It has been found that ghrelin significantly reduced blood pressure, urinary protein, and urine creatinine in rats with PE, at the meanwhile, ameliorated placental and fetal injuries. Second, ghrelin clearly inhibited placental Bax expression and circulating sFlt-1 as well as elevated placental Bcl-2 expression and circulating PIGF, restored apoptosis and invasion deficiency of trophoblast cells caused by LPS in vitro. Finally, transcriptomics indicated that nuclear factor kappa B (NF-κB) was the potential downstream pathway of ghrelin. Our findings illustrated that ghrelin supplementation significantly improved LPS-induced PE-like symptoms and adverse pregnancy outcomes in rats by alleviating placental apoptosis and promoting trophoblast migration.

Multiomic profiling of human clonal hematopoiesis reveals genotype and cell-specific inflammatory pathway activation.

ABSTRACT: Clonal hematopoiesis (CH) is an age-associated phenomenon that increases the risk of hematologic malignancy and cardiovascular disease. CH is thought to enhance disease risk through inflammation in the peripheral blood.1 Here, we profile peripheral blood gene expression in 66 968 single cells from a cohort of 17 patients with CH and 7 controls. Using a novel mitochondrial DNA barcoding approach, we were able to identify and separately compare mutant Tet methylcytosine dioxygenase 2 (TET2) and DNA methyltransferase 3A (DNMT3A) cells with nonmutant counterparts. We discovered the vast majority of mutated cells were in the myeloid compartment. Additionally, patients harboring DNMT3A and TET2 CH mutations possessed a proinflammatory profile in CD14+ monocytes through previously unrecognized pathways such as galectin and macrophage inhibitory factor. We also found that T cells from patients with CH, although mostly unmutated, had decreased expression of GTPase of the immunity associated protein genes, which are critical to T-cell development, suggesting that CH impairs T-cell function.

[Current situation and related of overweight and obesity in children aged 3-6 years old in Urumqi City in 2021].

OBJECTIVE: To understand the current situation and related factors of overweight and obesity in children aged 3-6 years old in Urumqi City. METHODS: From October to December 2021, a questionnaire survey was conducted on the general information of 1897 children and their fathers or mothers from 10 kindergartens in Urumqi City by stratified cluster sampling, and the height and weight of the children were measured. SPSS 25.0 was used for χ~2 test and Logistic regression analysis. RESULTS: There were 1897 children out of which 961(50.66%) were boys, 936(49.34%) were girls, 334(17.60%) were 3 years old, 592(31.21%)were 4 years old, 667(35.16%) were 5 years old, and 304(16.03%) were 6 years old. The prevalence rate of obesity and overweight in children aged 3-6 years old was 31.21%(592). Single factor analysis showed that child's age, the child's sex, the child's dietary habits, whether the child's father had a family history of obesity, whether the child's mother had a family history of obesity, whether the child's mother suffered from hypertension during pregnancy, whether the child's father smoked, whether the child's mother smoked during pregnancy(including passive smoking), the child's family per capita monthly income, the child's family structure type, and the child's mother's pregnancy age were all statistically significant(P<0.05 or P<0.01). The logistic regression analysis showed that child's age, the child's sex, the child's dietary habits, whether the child's father had a family history of obesity, whether the child's mother had a family history of obesity, whether the child's mother suffered from hypertension during pregnancy, whether the child's father smoked, whether the child's mother smoked during pregnancy(including passive smoking), the child's family structure type, and the child's mother's pregnancy age were overweight and obesity children aged 3-6 years old of related factors in Urumqi(P<0.05 or P<0.01). CONCLUSION: The detection rate of overweight and obesity in children aged 3-6 years old in Urumqi City is high.

Risk factors associated with tendon adhesions after hand tendon repair.

Background: Tendon adhesions after hand tendon repair are one of the most difficult complications of hand surgery and can cause severe disability. This study aimed to assess the risk factors associated with tendon adhesions after hand tendon repair to provide a theoretical foundation for the early prevention of tendon adhesions in patients with tendon injuries. Moreover, this study intends to increase doctors' awareness of the issue and serves as a reference for developing new prevention and treatment strategies. Methods: We retrospectively analyzed 1,031 hand trauma cases that underwent repair after finger tendon injury in our department between June 2009 and June 2019. Tendon adhesions, tendon injury zones, and other relevant information were collected, summarized, and analyzed. The significance of data was determined using a t-test or Pearson's chi-square test, and odds ratios (OR) were calculated using logistic regression tests to describe factors associated with post-tendon repair adhesions. Results: A total of 1,031 patients were enrolled in this study. There were 817 males and 214 females with an average age of 34.98 (2-82) years. The injured side included 530 left and 501 right hands. Postoperative finger tendon adhesions occurred in 118 cases (11.45%), including 98 males and 20 females, 57 left and 61 right hands. The risk factors for the total sample in the descending order were degloving injury, no functional exercise, zone II flexor tendon injury, time from injury to surgery >12 h, combined vascular injury, and multiple tendon injuries. The flexor tendon sample shared the same risk factors as the total sample. Risk factors for the extensor tendon sample were degloving injury, no functional exercise. Conclusions: Clinicians should pay close attention to patients with tendon trauma in hand having the following risk factors: degloving injury, zone II flexor tendon injury, lack of functional exercise, time from injury to surgery >12 h, combined vascular injury, and multiple tendon injuries. Due to the high risk of post-repair adhesions in patients with the conditions mentioned above, individualized treatment measures should be designed for the risk factors, and postoperative functional exercise of the hand is required.

Tanshinone I restrains osteosarcoma progression by regulating circ_0000376/miR-432-5p/BCL2 axis.

Circular RNAs (circRNAs) have been identified as important regulators in cancer progression. Nevertheless, little is known about the biological function of circ_0000376 in the progression of osteosarcoma (OS). Cell viability, colony formation ability, apoptosis, and motility were analyzed by Cell Counting Kit-8 assay, colony formation assay, flow cytometry, and transwell assays. Cellular glycolytic metabolism was analyzed using commercial kits. RT-qPCR and Western blot assay were performed to analyze RNA and protein expression in OS tissues and cells. Starbase software was used to establish circRNA-microRNA (miRNA)-messenger RNA linkage, and intermolecular interaction was verified by dual-luciferase reporter assay. Xenograft tumor assay was conducted to analyze the effects of Tanshinone I (Tan I) and circ_0000376 on xenograft tumor growth in vivo. Tan I treatment suppressed the viability, migration, invasion, and glycolysis and triggered the apoptosis of OS cells. Tan I treatment markedly down-regulated circ_0000376 expression in OS cells. The addition of circ_0000376 plasmid largely rescued the malignant behaviors of OS cells upon Tan I exposure. Circ_0000376 interacted with miR-432-5p in OS cells. Circ_0000376 overexpression-mediated protective effects in Tan I-induced OS cells were partly attenuated by the accumulation of miR-432-5p. miR-432-5p bound to the 3' untranslated region (3'UTR) of B-cell leukemia/lymphoma 2 (BCL2) in OS cells. miR-432-5p interference-induced effects in Tan I-treated OS cells were partly overturned by the silence of BCL2. Circ_0000376 can act as miR-432-5p sponge to up-regulate BCL2 expression in OS cells. Circ_0000376 silencing contributed to the anti-tumor effect of Tan I on the growth of xenograft tumors in vivo. Tan I exerted an anti-tumor role in OS progression by targeting circ_0000376/miR-432-5p/BCL2 axis.

[A case report of multiple dentigerous cyst of mandible and review of literature].

Dentigerous cyst belongs to one kind of odontogenic cysts, and is also known as follicular cyst. After the formation of the crown or root of the tooth, liquid exudates between the residual enamel epithelium and the crown surface to form odontogenic cysts. Multiple odontogenic cysts are rare in the oral and maxillofacial regions, especially in different areas of the jaw. In this paper, we reported case with multiple odontogenic cysts and discussed its etiology,pathological classification,differential diagnosis and treatment.

Primary central nervous system lymphoma with no enhancement initially and no significant progression over a long term: a case report and review of the literature.

Primary central nervous system lymphoma, a rare primary intracranial tumor, is highly malignant and usually associated with poor prognosis. Recent years, owing to the remarkable progress in intervention techniques, survival time reported has been significantly prolonged. Strategies targeting alleviation and remission are primarily depended on the early diagnosis. However, due to the heterogeneity of the clinical symptoms and imaging features, the disease is frequently misdiagnosed especially in the early phase, rendering a delay of optimal treatment. Herein, we reported the case of a 61-year-old man who was initially misdiagnosed as demyelinating encephalopathy. MRI images showed multifocal lesions across the cerebral cortex and deep white matter, which are not strengthened on contrast enhancements. In respect of clinical symptoms, no significant progress was observed over about 11 months. Finally, the diagnosis was revealed by brain biopsy. After reviewing all the images of the patient, we found that the corpus callosum was involved early in the course of the disease. Therefore, for multifocal intracranial lesions involving the corpus callosum, we should always be vigilant about the possibility of primary central nervous system lymphoma. Histopathological examination of brain biopsy is helpful for early definitive diagnosis.

Whole exome sequencing reveals novel NOV and DCAF13 variants in a Chinese pedigree with familial cortical myoclonic tremor with epilepsy.

OBJECTIVE: We report a large new family of familial cortical myoclonic tremor with epilepsy(FCMTE) from China and identify the possible causative gene(s) for the family. METHOD: Whole exome sequencing of blood genomic DNA from 4 patients and 2 unaffected family members were performed. Detected variants and their cosegregation were confirmed by Sanger sequencing. RESULTS: We identified c.20 G > C variant in the DCAF13 gene and c.983 T > C variant in the NOV gene cosegregating in the family. There was no additional cross-over in the family to narrow to one gene. The two DCAF13 and NOV gene variants are located on 8q23.3 and 8q24.12, which is consistent with the location 8q23.3-q24.13 reported previously for a group of Japanese families. The DCAF13 variant is located in alternative transcription start site(TSS) and the function of alternative TSS is unknown. The missense NOV variant is near the C terminus in a site that is highly conserved across species. It was predicted to be deleterious on protein function. CONCLUSIONS: In this study, we identify two novel variants in the DCAF13 and NOV genes associated with FCMTE in Asian populations. The interval between two variants is 15.6Mb, which is very close to each other. Future studies of additional families with this phenotype are warranted to confirm whether it is rare bigenic or monogenic inheritance.

Effect of Stress Ratio and Loading Frequency on the Corrosion Fatigue Behavior of Smooth Steel Wire in Different Solutions.

In this work, the effects of loading condition and corrosion solution on the corrosion fatigue behavior of smooth steel wire were discussed. The results of polarization curves and weight loss curves showed that the corrosion of steel wire in acid solution was more severe than that in neutral and alkaline solutions. With the extension of immersion time in acid solution, the cathodic reaction of steel wire gradually changed from the reduction of hydrogen ion to the reduction of oxygen, but was always the reduction of hydrogen ion in neutral and alkaline solutions. The corrosion kinetic parameters and equivalent circuits of steel wires were also obtained by simulating the Nyquist diagrams. In corrosion fatigue test, the effect of stress ratio and loading frequency on the crack initiation mechanism was emphasized. The strong corrosivity of acid solution could accelerate the nucleation of crack tip. The initiation mechanism of crack under different conditions was summarized according to the side and fracture surface morphologies. For the crack initiation mechanism of anodic dissolution, the stronger the corrosivity of solution was, the more easily the fatigue crack source formed, while, for the crack initiation mechanism of deformation activation, the lower stress ratio and higher frequency would accelerate the generation of corrosion fatigue crack source.

Antitumor effects of a dual cancer-specific oncolytic adenovirus on colorectal cancer in vitro and in vivo.

The efficacy and specificity of treatment are major challenges for cancer gene therapy. Oncolytic virotherapy is an attractive drug delivery platform for cancer gene therapy. In the present study, the dual-specific antitumor oncolytic adenovirus, Ad-Apoptin-hTERT-E1a, was used to infect SW1116 human colorectal carcinoma (CRC) cell lines and CT26 mouse-CRC-cell bearing BALB/c mouse models for testing antitumor effects in vitro and in vivo. The in vitro assays revealed that infection with Ad-Apoptin-hTERT-E1a induced a significant cytotoxic effect on the CRC cell line, SW1116; however, the normal human cell line, GES, was only slightly inhibited by the recombinant adenovirus. Acridine orange and ethidium bromide staining and an annexin V assay indicated that infection of SW1116 cells with Ad-Apoptin-hTERT-E1a resulted in a significant induction of apoptosis. Furthermore, western blotting and flow cytometry revealed a decrease in the mitochondrial membrane potential (MMP), the release of cytochrome c and the activation of caspase 3, 6 and 7 in Ad-Apoptin-hTERT-E1a-infected SW1116 cells. In the animal models, Ad-Apoptin-hTERT-E1a was shown to significantly inhibit tumor growth and extend the survival times of the animals. Therefore, the experimental results indicated that Ad-Apoptin-hTERT-E1a has potential for application in tumor gene therapy.

Preclinical pharmacology and toxicology study of Ad-hTERT-E1a-Apoptin, a novel dual cancer-specific oncolytic adenovirus.

Clinical studies have demonstrated that conditionally replicating adenovirus is safe. We constructed an oncolytic adenovirus, Ad-hTERT-E1a-Apoptin, using a cancer-specific promoter (human telomerase reverse transcriptase promoter, hTERTp) and a cancer cell-selective apoptosis-inducing gene (Apoptin). Ad-hTERT-E1a-Apoptin was proven effective both in vitro and in vivo in our previous study. In this study, the preclinical safety profiles of Ad-hTERT-E1a-Apoptin in animal models were investigated. At doses of 5.0×10(8), 2.5×10(9), and 1.25×10(10) viral particles (VP)/kg, Ad-hTERT-E1a-Apoptin had no adverse effects on mouse behavior, muscle cooperation, sedative effect, digestive system, and nervous systems, or on beagle cardiovascular and respiratory systems at 5.0×10(8), 2.5×10(9), and 1.25×10(10) VP/kg doses. In acute toxicity tests in mice, the maximum tolerated dose>5×10(10) VP/kg. There was no inflammation or ulceration at the injection sites within two weeks. In repeat-dose toxicological studies, the no observable adverse effect levels of Ad-hTERT-E1a-Apoptin in rats (1.25×10(10) VP/kg) and beagles (2.5×10(9) VP/kg) were 62.5- and 12.5-fold of the proposed clinical dose, respectively. The anti-virus antibody was produced in animal sera. Bone marrow examination revealed no histopathological changes. Guinea pigs sensitized by three repeated intraperitoneal injections of 1.35×10(10) VP/mL Ad-hTERT-E1a-Apoptin each and challenged by one intravenous injection of 1.67×10(8) VP/kg Ad-hTERT-E1a-Apoptin did not exhibit any sign of systemic anaphylaxis. Our data from different animal models suggest that Ad-hTERT-E1a-Apoptin is a safe anti-tumor therapeutic agent.

Three epilepsy-associated GABRG2 missense mutations at the γ+/ß- interface disrupt GABAA receptor assembly and trafficking by similar mechanisms but to different extents.

We compared the effects of three missense mutations in the GABAA receptor γ2 subunit on GABAA receptor assembly, trafficking and function in HEK293T cells cotransfected with α1, ß2, and wildtype or mutant γ2 subunits. The mutations R82Q and P83S were identified in families with genetic epilepsy with febrile seizures plus (GEFS+), and N79S was found in a single patient with generalized tonic-clonic seizures (GTCS). Although all three mutations were located in an N-terminal loop that contributes to the γ+/ß- subunit-subunit interface, we found that each mutation impaired GABAA receptor assembly to a different extent. The γ2(R82Q) and γ2(P83S) subunits had reduced α1ß2γ2 receptor surface expression due to impaired assembly into pentamers, endoplasmic reticulum (ER) retention and degradation. In contrast, γ2(N79S) subunits were efficiently assembled into GABAA receptors with only minimally altered receptor trafficking, suggesting that N79S was a rare or susceptibility variant rather than an epilepsy mutation. Increased structural variability at assembly motifs was predicted by R82Q and P83S, but not N79S, substitution, suggesting that R82Q and P83S substitutions were less tolerated. Membrane proteins with missense mutations that impair folding and assembly often can be "rescued" by decreased temperatures. We coexpressed wildtype or mutant γ2 subunits with α1 and ß2 subunits and found increased surface and total levels of both wildtype and mutant γ2 subunits after decreasing the incubation temperature to 30°C for 24h, suggesting that lower temperatures increased GABAA receptor stability. Thus epilepsy-associated mutations N79S, R82Q and P83S disrupted GABAA receptor assembly to different extents, an effect that could be potentially rescued by facilitating protein folding and assembly.

Generation of an attenuated Tiantan vaccinia virus by deletion of the ribonucleotide reductase large subunit.

Attenuation of the virulence of vaccinia Tiantan virus (VTT) underlies the strategy adopted for mass vaccination campaigns. This strategy provides advantages of safety and efficacy over traditional vaccines and is aimed at minimization of adverse health effects. In this study, a mutant form of the virus, MVTT was derived from VTT by deletion of the ribonucleotide reductase large subunit (R1) (TI4L). Compared to wild-type parental (VTT) and revertant (VTT-rev) viruses, virulence of the mutant MVTT was reduced by 100-fold based on body weight reduction and by 3,200-fold based on determination of the intracranial 50% lethal infectious dose. However, the immunogenicity of MVTT was equivalent to that of the parental VTT. We also demonstrated that the TI4L gene is not required for efficient replication. These data support the conclusion that MVTT can be used as a replicating virus vector or as a platform for the development of vaccines against infectious diseases and for cancer therapy.

Anti-tumor effects of an oncolytic adenovirus expressing hemagglutinin-neuraminidase of Newcastle disease virus in vitro and in vivo.

Oncolytic virotherapy has been an attractive drug platform for targeted therapy of cancer over the past few years. Viral vectors can be used to target and lyse cancer cells, but achieving good efficacy and specificity with this treatment approach is a major challenge. Here, we assessed the ability of a novel dual-specific anti-tumor oncolytic adenovirus, expressing the hemagglutinin-neuraminidase (HN) gene from the Newcastle disease virus under the human telomerase reverse transcriptase (hTERT) promoter (Ad-hTERTp-E1a-HN), to inhibit esophageal cancer EC-109 cells in culture and to reduce tumor burden in xenografted BALB/c nude mice. In vitro, infection with Ad-hTERT-E1a-HN could inhibit the growth of EC-109 cells significantly and also protect normal human liver cell line L02 from growth suppression in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Ad-hTERT-E1a-HN also effectively and selectively decreased the sialic acid level on EC-109 cells, but not on L02 cells. Furthermore, Ad-hTERT-E1a-HN was shown to induce the apoptosis pathway via acridine orange and ethidium bromide staining (AO/EB staining), increase reactive oxygen species (ROS), reduce mitochondrial membrane potential and release cytochrome c. In vivo, xenografted BALB/c nude mice were treated via intratumoral or intravenous injections of Ad-hTERT-E1a-HN. Although both treatments showed an obvious suppression in tumor volume, only Ad-hTERT-E1a-HN delivered via intratumoral injection elicited a complete response to treatment. These results reinforced previous findings and highlighted the potential therapeutic application of Ad-hTERT-E1a-HN for treatment of esophageal cancer in clinical trials.

Potent growth-inhibitory effect of a dual cancer-specific oncolytic adenovirus expressing apoptin on prostate carcinoma.

Apoptin is a chicken anemia virus-derived, p53-independent, bcl-2-insensitive apoptotic protein with the ability to specifically induce apoptosis in various human tumor cells, but not in normal cells. To explore the use of apoptin in tumor gene therapy, we assessed a recombinant adenovirus expressing the apoptin protein (Ad-hTERTp-E1a-Apoptin) in order to determine its lethal and growth-inhibitory effects on PC-3 and RM-1 cells in vitro and its antitumor effect on solid tumors in vivo. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT), acridine orange (AO)/ethidium bromide (EB), 4'-6-diamidino-2-phenylindole (DAPI), and Annexin V assays showed that Ad-hTERTp-E1a-Apoptin inhibited the proliferation of PC-3 and RM-1 cells in vitro by inducing apoptosis of prostate cancer cells, and that this inhibitory effect was dose and time-dependent. In the animal models, Ad-hTERTp-E1a-Apoptin significantly inhibited tumor growth and extended the lifespan of animals. Experimental results indicate that Ad-hTERTp-E1a-Apoptin has a potential application in tumor gene therapy.

Lipopolysaccharide-dependent interaction between PU.1 and c-Jun determines production of lipocalin-type prostaglandin D synthase and prostaglandin D2 in macrophages.

Previously, we reported that expression of lipocalin-prostaglandin D synthase (L-PGDS) is inducible in macrophages and protects from Pseudomonas pneumonia. Here, we investigated the mechanism by which L-PGDS gene expression is induced in macrophages. A promoter analysis of the murine L-PGDS promoter located a binding site of PU.1, a transcription factor essential for macrophage development and inflammatory gene expression. A chromatin immunoprecipitation assay showed that PU.1 bound to the cognate site in the endogenous L-PGDS promoter in response to LPS. Overexpression of PU.1, but not of PU.1(S148A), a mutant inert to casein kinase II (CKII) or NF-kappaB-inducing kinase (NIK), induced L-PGDS in RAW 264.7 cells. Conversely, siRNA silencing of PU.1 expression blunted productions of L-PGDS and prostaglandin D2 (PGD(2)). LPS treatment induced formation of the complex of PU.1 and cJun on the PU.1 site, but inactivation of cJun by treatment with JNK or p38 kinase inhibitor abolished the complex, and suppressed PU.1 transcriptional activity for L-PGDS gene expression. Together, these results show that PU.1, activated by CKII or NIK, cooperates with MAPK-activated cJun to maximally induce L-PGDS expression in macrophages following LPS treatment, and suggest that PU.1 participates in innate immunity through the production of L-PGDS and PGD(2).

Developmental modulation of GABA(A) receptor function by RNA editing.

Adenosine-to-inosine (A-to-I) editing of RNA transcripts is an increasingly recognized cellular strategy to modulate the function of proteins involved in neuronal excitability. We have characterized the editing of transcripts encoding the alpha3 subunit of heteromeric GABA(A) receptors (Gabra3), in which a genomically encoded isoleucine codon (ATA) is converted to a methionine codon (ATI) in a region encoding the predicted third transmembrane domain of this subunit. Editing at this position (I/M site) was regulated in a spatiotemporal manner with approximately 90% of the Gabra3 transcripts edited in most regions of adult mouse brain, but with lower levels of editing in the hippocampus. Editing was low in whole-mouse brain at embryonic day 15 and increased during development, reaching maximal levels by postnatal day 7. GABA-evoked current in transfected cells expressing nonedited alpha3(I)beta3gamma2L GABA(A) receptors activated more rapidly and deactivated much more slowly than edited alpha3(M)beta3gamma2L receptors. Furthermore, currents from nonedited alpha3(I)beta3gamma2L receptors were strongly outwardly rectifying (corresponding to chloride ion influx), whereas currents from edited alpha3(M)beta3gamma2L receptors had a more linear current/voltage relationship. These studies suggest that increased expression of the nonedited alpha3(I) subunit during brain development, when GABA is depolarizing, may allow the robust excitatory responses that are critical for normal synapse formation. However, the strong chloride ion influx conducted by receptors containing the nonedited alpha3(I) subunit could act as a shunt to prevent excessive excitation, providing the delicate balance necessary for normal neuronal development.

NIK is involved in nucleosomal regulation by enhancing histone H3 phosphorylation by IKKalpha.

The exact physiological role of NF-kappaB-inducing kinase (NIK) in the NF-kappaB activation pathway has not been defined, although it is an upstream kinase of IKKalpha. Recent studies have indicated that IKKalpha is a nucleosomal modifier of NF-kappaB signaling. We hypothesized that NIK generates a proximal signal that contributes to IKKalpha modification of nucleosomal structure through phosphorylation of histone H3 and enhancement of target gene expression. By using a chromatin immunoprecipitation assay, our data show that endogenous IKKalpha is recruited to the promoter site of several NF-kappaB-dependent genes in macrophages. Our data show that immunoreactive NIK is rapidly recruited to nuclear compartment in macrophages in response to treatment with endotoxin where it augments phosphorylation of histone H3 by inducing phosphorylation and kinase activity of IKKalpha. A small interfering RNA knockdown of NIK markedly reduces phosphorylation of histone H3 in endotoxin treated macrophages. These data, together, demonstrate a novel role for NIK as a histone H3 modifier, through an accessory pathway from NIK to IKKalpha, that could play an important role in the endotoxin response through modification of nucleosomal structure.