AKAP12 Research Articles

Tail-anchored membrane protein SLMAP3 is essential for targeting centrosomal proteins to the nuclear envelope in skeletal myogenesis.

The positioning and communication between the nucleus and centrosomes are essential in cell division, differentiation and tissue formation. During skeletal myogenesis, the nuclei become evenly spaced with the switch of the microtubule-organizing centre (MTOC) from the centrosome to the nuclear envelope (NE). We report that the tail-anchored sarcolemmal membrane associated protein 3 (SLMAP3), a component of the MTOC and NE, is crucial for myogenesis because its deletion in mice leads to a reduction in the NE-MTOC formation, mislocalization of the nuclei, dysregulation of the myogenic programme and abnormal embryonic myofibres. SLMAP3-/- myoblasts also displayed a similar disorganized distribution of nuclei with an aberrant NE-MTOC and defective myofibre formation and differentiation programming. We identified novel interactors of SLMAP3, including pericentrin, PCM1 (pericentriolar material 1), AKAP9 (A-kinase anchoring protein 9), kinesin-1 members Kif5B (kinesin family member 5B), KCL1 (kinesin light chain 1), KLC2 (kinesin light chain 2) and nuclear lamins, and observed that the distribution of centrosomal proteins at the NE together with Nesprin-1 was significantly altered by the loss of SLMAP3 in differentiating myoblasts. SLMAP3 is believed to negatively regulate Hippo signalling, but its loss was without impact on this pathway in developing muscle. These results reveal that SLMAP3 is essential for skeletal myogenesis through unique mechanisms involving the positioning of nuclei, NE-MTOC dynamics and gene programming.

The A-kinase anchoring protein Yotiao decrease the ER calcium content by inhibiting the store operated calcium entry

The meticulous regulation of ER calcium (Ca2+) homeostasis is indispensable for the proper functioning of numerous cellular processes. Disrupted ER Ca2+ balance is implicated in diverse diseases, underscoring the need for a systematic exploration of its regulatory factors in cells. Our recent genomic-scale screen identified a scaffolding protein A-kinase anchoring protein 9 (AKAP9) as a regulator of ER Ca2+ levels, but the underlying molecular mechanisms remain elusive. Here, we reveal that Yotiao, the smallest splicing variant of AKAP9 decreased ER Ca2+ content in animal cells. Additional testing using a combination of Yotiao truncations, knock-out cells and pharmacological tools revealed that, Yotiao does not require most of its interactors, including type 1 inositol 1,4,5-trisphosphate receptors (IP3R1), protein kinase A (PKA), protein phosphatase 1 (PP1), adenylyl cyclase type 2 (AC2) and so on, to reduce ER Ca2+ levels. However, adenylyl cyclase type 9 (AC9), which is known to increases its cAMP generation upon interaction with Yotiao for the modulation of potassium channels, plays an essential role for Yotiao's ER-Ca2+-lowering effect. Mechanistically, Yotiao may work through AC9 to act on Orai1-C terminus and suppress store operated Ca2+ entry, resulting in reduced ER Ca2+ levels. These findings not only enhance our comprehension of the interplay between Yotiao and AC9 but also contribute to a more intricate understanding of the finely tuned mechanisms governing ER Ca2+ homeostasis.

A mutation in the cardiac KV7.1 channel possibly disrupts interaction with Yotiao protein

Here, we characterized the p.Arg583His (R583H) Kv7.1 mutation, identified in two unrelated families suffered from LQT syndrome. This mutation is located in the HС-HD linker of the cytoplasmic portion of the Kv7.1 channel. This linker, together with HD helix are responsible for binding the A-kinase anchoring protein 9 (AKAP9), Yotiao. We studied the electrophysiological characteristics of the mutated channel expressed in CHO–K1 along with KCNE1 subunit and Yotiao protein, using the whole-cell patch-clamp technique. We found that R583H mutation, even at the heterozygous state, impedes IKs activation. Molecular modeling showed that HС and HD helixes of the C-terminal part of Kv7.1 channel are swapped along the C-terminus length of the channel and that R583 position is exposed to the outer surface of HC-HD tandem coiled-coil. Interestingly, the adenylate cyclase activator, forskolin had a smaller effect on the mutant channel comparing with the WT protein, suggesting that R583H mutation may disrupt the interaction of the channel with the adaptor protein Yotiao and, therefore, may impair phosphorylation of the KCNQ1 channel.

AKAP12 Upregulation Associates With PDE8A to Accelerate Cardiac Dysfunction.

In heart failure, signaling downstream the β2-adrenergic receptor is critical. Sympathetic stimulation of β2-adrenergic receptor alters cAMP (cyclic adenosine 3',5'-monophosphate) and triggers PKA (protein kinase A)-dependent phosphorylation of proteins that regulate cardiac function. cAMP levels are regulated in part by PDEs (phosphodiesterases). Several AKAPs (A kinase anchoring proteins) regulate cardiac function and are proposed as targets for precise pharmacology. AKAP12 is expressed in the heart and has been reported to directly bind β2-adrenergic receptor, PKA, and PDE4D. However, its roles in cardiac function are unclear. cAMP accumulation in real time downstream of the β2-adrenergic receptor was detected for 60 minutes in live cells using the luciferase-based biosensor (GloSensor) in AC16 human-derived cardiomyocyte cell lines overexpressing AKAP12 versus controls. Cardiomyocyte intracellular calcium and contractility were studied in adult primary cardiomyocytes from male and female mice overexpressing cardiac AKAP12 (AKAP12OX) and wild-type littermates post acute treatment with 100-nM isoproterenol (ISO). Systolic cardiac function was assessed in mice after 14 days of subcutaneous ISO administration (60 mg/kg per day). AKAP12 gene and protein expression levels were evaluated in left ventricular samples from patients with end-stage heart failure. AKAP12 upregulation significantly reduced total intracellular cAMP levels in AC16 cells through PDE8. Adult primary cardiomyocytes from AKAP12OX mice had significantly reduced contractility and impaired calcium handling in response to ISO, which was reversed in the presence of the selective PDE8 inhibitor (PF-04957325). AKAP12OX mice had deteriorated systolic cardiac function and enlarged left ventricles. Patients with end-stage heart failure had upregulated gene and protein levels of AKAP12. AKAP12 upregulation in cardiac tissue is associated with accelerated cardiac dysfunction through the AKAP12-PDE8 axis.

Expression of RASSF1A, DIRAS3, and AKAP9 Genes in Thyroid Lesions: Implications for Differential Diagnosis and Prognosis of Thyroid Carcinomas.

Thyroid carcinoma is the primary endocrine malignancy worldwide. The preoperative examination of thyroid tissue lesion is often unclear. Approximately 25% of thyroid cancers cannot be diagnosed definitively without post-surgery histopathological examination. The assessment of diagnostic and differential markers of thyroid cancers is needed to improve preoperative diagnosis and reduce unnecessary treatments. Here, we assessed the expression of RASSF1A, DIRAS3, and AKAP9 genes, and the presence of BRAF V600E point mutation in benign and malignant thyroid lesions in a Polish cohort (120 patients). We have also performed a comparative analysis of gene expression using data obtained from the Gene Expression Omnibus (GEO) database (307 samples). The expression of RASSF1A and DIRAS3 was decreased, whereas AKAP9's was increased in pathologically changed thyroid compared with normal thyroid tissue, and significantly correlated with e.g., histopathological type of lesion papillary thyroid cancer (PTC) vs follicular thyroid cancer (FTC), patient's age, tumour stage, or its encapsulation. The receiver operating characteristic (ROC) analysis for the more aggressive FTC subtype differential marker suggests value in estimating RASSF1A and AKAP9 expression, with their area under curve (AUC), specificity, and sensitivity at 0.743 (95% CI: 0.548-0.938), 82.2%, and 66.7%; for RASSF1A, and 0.848 (95% CI: 0.698-0.998), 54.8%, and 100%, for AKAP9. Our research gives new insight into the basis of the aggressiveness and progression of thyroid cancers, and provides information on potential differential markers that may improve preoperative diagnosis.

Establishment of the Bcwm.2 Cell Line As a BTK-Inhibitor Resistant, BCL2 Inhibitor Sensitive in Vitro and In Vivo Study Model for Waldenström's Macroglobulinemia

Background: Waldenström's macroglobulinemia (WM) is an indolent B-cell lymphoproliferative disorder characterized by bone marrow (BM) infiltration with lymphoplasmacytic lymphoma and monoclonal immunoglobulin M (IgM) production. Mutations in MYD88 are present in 95-97% of WM patients. Deletions involving chromosome 6q (del6q) are found in up to 50% of WM patients, and include genes that regulate MYD88, BCL2 and apoptotic signaling. Cell lines can play a pivotal role as disease models, contributing to a comprehensive understanding of WM biology and advancing therapeutic strategies. The availability of cell lines for the study of WM remains limited, and none demonstrate del6q. Patient and Methods: We developed and characterized a novel cell line (BCWM.2) from long-term cultures of CD19 + selected BM lymphoplasmacytic cells from a symptomatic, treatment naive WM patient who then received ibrutinib monotherapy on a clinical trial. The patient attained a major response to treatment, and after 2 years progressed. The patient underwent serial bone marrow biopsies, and extensive genomic and transcriptome analysis of his tumor during the study, and the corresponding cell line established at baseline. An in vivo xenograft mouse model of BCWM.2 was also established in NOD SCID mice, and the origin of the xenografted tumor was confirmed by genomic sequencing and immunohistochemistry. Results: BCWM.2 cells exhibited morphologic and immunophenotypic characteristics resembling lymphoplasmacytic cells and demonstrated robust propagation when co-cultured with HS-5 stromal cells in IMDM medium supplemented with 20% FBS. Flow cytometric analysis revealed that BCWM.2 exhibited an immunophenotype consistent with the source WM patient. Whole genome sequencing demonstrated that both BCWM.2 cells and original patient WM cells carried somatic activating mutation in MYD88 (S243N) and shared trisomy in chromosomes 3 and 12, heterozygous deletion of 6q, and amplification of 6p. Notably, a novel mutation in the SRC family member LYN (I297N; T>A), a component of BCR, was identified in BCWM.2 but not the original patient tumor. The I297N mutation found in the regulatory hinge region is predicted to cause activation of LYN. At time of progression on ibrutinib, the dominant clone that emerged in the patient's tumor also carried the I297N mutation. Additionally, mutated genes in BCWM.2 included histone deacetylase HDAC5, tumor suppressor RUNX3, B-cell transcriptional activator SPI1, and AKAP9 (A-Kinase Anchoring Protein 9). Transcriptome analysis showed shared expression patterns between BCWM.2 and patient tumor samples, including diminished gene expression of chromosome 6q. Drug response testing revealed that BCWM.2 cells did not respond to the BTK-inhibitors ibrutinib, zanubrutinib or pirtobrutinib but were sensitive to the BCL2 inhibitor venetoclax. Furthermore, BCWM.2 cells readily engrafted in NOD-SCID mice by direct subcutaneous injection of 2 x 10^6 cells/mouse. Tumor growth (~500 mm^3) was observed in the mice four weeks post-inoculation. Importantly, follow-up evaluations demonstrated serial increases in human IgM levels in the mouse sera post-engraftment. Moreover, BCWM.2 engraftment was confirmed by immunohistochemistry with tumors exhibiting intermediate lymphoid cell morphology with plasmacytoid differentiation, CD20 and MUM1 expression, clonality for lambda light chain and IgM heavy chain, 60% KI67 staining. Whole exome sequencing of engrafted tumors further confirmed the presence of the MYD88 S243N and LYN I297N mutations detected in the cell line and the patient at the time of ibrutinib progression. Conclusions: BCWM.2 represents a novel, BTK-inhibitor resistant, BCL2 inhibitor sensitive WM cell line that demonstrates MYD88 (S243N) and LYN (I297N) somatic activating mutations, and deletions of 6q. BCWM.2 thereby provides an important new disease appropriate cell model for the in vitro and in vivo study of WM, including the development of targeted therapies for this disease.

THU412 Role of Glucocorticoid On Bone Metabolism Through AKAP13

Abstract Disclosure: K. Igarashi: None. A. Ishida: None. H. Koide: None. K. Yokote: None. It is not completely clear to what extent glucocorticoids are involved in which stages and sites of bone differentiation, development, and maintenance. we investigated the mechanism of glucocorticoid regulation through the regulation of Rho activation using a regulatory system for the expression of the RhoA activator AKAP13. To examine the effect of glucocorticoids on preosteoblasts, immortalized bone marrow mesenchymal stem cells (imBMSCs) were sown in 6-well plates at a concentration of 2x105/well and treated with various concentrations (0-1000 nM) of dexamethasone (Dex) 24 hr later, and The expression of GILZ, osteoblast and adipocyte-associated markers were evaluated using qRT-PCR. AKAP13 expression vector and AKAP13 siRNA were used to examine the response to Dex. GILZ was induced in a Dex-dependent manner on both day1 and day4. In the differentiation phase, PPARG2 expression was not changed by Dex, but GILZ was induced in a similar Dex-dependent manner. In proliferating imBMSCs, Dex treatment tended to enhance PPARG2 expression in a dose-dependent manner by introducing AKAP13 expression vectors. On the other hand, AKAP13 gene expression was significantly down-regulated in imBMSCs treated with AKAP13 siRNA, and Alp2 mRNA was up-regulated in imBMSCs treated with Dex compared to those not treated with Dex. It has a nuclear receptor binding domain and is known to be involved in osteogenesis. On the other hand, AKAP13 expression was decreased by osteoblast differentiation in an in vitro system, suggesting that AKAP13 may influence the regulation of GC action between the proliferative and differentiation phases of BMSCs. Presentation: Thursday, June 15, 2023

AKAP12 promotes cancer stem cell-like phenotypes and activates STAT3 in colorectal cancer.

Cancer stem cells (CSCs) have unique biological characteristics, including tumorigenicity, immortality, and chemoresistance. Colorectal CSCs have been identified and isolated from colorectal cancers by various methods. AKAP12, a scaffolding protein, is considered to act as a potential suppressor in colorectal cancer, but its role in CSCs remains unknown. In this study, we investigated the function of AKAP12 in Colorectal CSCs. Herein, Colorectal CSCs were enriched by cell culture with a serum-free medium. CSC-associated characteristics were evaluated by Flow cytometry assay and qPCR. AKAP12 gene expression was regulated by lentiviral transfection assay. The tumorigenicity of AKAP12 in vivo by constructing a tumor xenograft model. The related pathways were explored by qPCR and Western blot. The depletion of AKAP12 reduced colony formation, sphere formation, and expression of stem cell markers in colorectal cancer cells, while its knockdown decreased the volume and weight of tumor xenografts in vivo. AKAP12 expression levels also affected the expression of stemness markers associated with STAT3, potentially via regulating the expression of protein kinase C. This study suggests Colorectal CSCs overexpress AKAP12 and maintain stem cell characteristics through the AKAP12/PKC/STAT3 pathway. AKAP12 may be an important therapeutic target for blocking the development of colorectal cancer in the field of cancer stem cells.

A-Kinase Anchoring Protein 9 Promotes Gastric Cancer Progression as a Downstream Effector of Cadherin 1.

Background Genetic studies identified a dozen of frequently mutated genes in gastric cancer, such as cadherin 1 (CDH1) and A-kinase anchoring protein 9 (AKAP9). Of note, genetic alterations including depletion and amplification frameshift mutations of AKAP9 have been observed in 10–15% of gastric cancer patients. However, it is unknown of the expression and role of AKAP9 in gastric cancer. This study is aimed to characterize the expression and function of AKAP9 in gastric cancer. Methods Using qRT-PCR, we analyzed the mRNA levels of AKAP9 in gastric cancer patient samples. We investigated the role of AKAP9 in gastric cancer by performing cell proliferation assay, transwell assay, and mouse xenograft assay. Results AKAP9 was upregulated in gastric cancer patients. Overexpression of AKAP9 promoted cell proliferation, migration, and gastric tumor growth. Loss of CDH1 elevated AKAP9 mRNA and protein levels. Conclusion Our study demonstrates that AKAP9 functions as an oncoprotein to promote gastric cancer cell proliferation, migration, and tumor growth. Moreover, we reveal a possible molecular link showing that AKAP9 is a critical effector downstream of CDH1 in gastric cancer.

Loss of Unconventional Myosin VI Affects cAMP/PKA Signaling in Hindlimb Skeletal Muscle in an Age-Dependent Manner.

Myosin VI (MVI) is a unique unconventional myosin ubiquitously expressed in metazoans. Its diverse cellular functions are mediated by interactions with a number of binding partners present in multi-protein complexes. MVI is proposed to play important roles in muscle function and myogenesis. Previously, we showed that MVI is present in striated muscles and myogenic cells, and MVI interacts with A-kinase anchoring protein 9 (AKAP9), a scaffold for PKA and its regulatory proteins. Since PKA directly phosphorylates the MVI cargo binding domain, we hypothesized that the cellular effects of MVI are mediated by the cAMP/PKA signaling pathway, known to play important roles in skeletal muscle metabolism and myogenesis. To elucidate the potential role of MVI in PKA signaling in hindlimb muscle function, we used mice lacking MVI (Snell’s waltzer, SV), considered as natural MVI knockouts, and heterozygous littermates. We used muscles isolated from newborn (P0) as well as 3- and 12-month-old adult mice. We observed a significant increase in the muscle to body mass ratio, which was most evident for the soleus muscle, as well as changes in fiber size, indicating alterations in muscle metabolism. These observations were accompanied by age-dependent changes in the activity of PKA and cAMP/PKA-dependent transcriptional factor (CREB). Additionally, the levels of adenylate cyclase isoforms and phosphodiesterase (PDE4) were age-dependent. Also, cAMP levels were decreased in the muscle of P0 mice. Together, these observations indicate that lack of MVI impairs PKA signaling and results in the observed alterations in the SV muscle metabolism, in particular in newborn mice.

Alzheimer's disease associated AKAP9 I2558M mutation alters posttranslational modification and interactome of tau and cellular functions in CRISPR-edited human neuronal cells.

Alzheimer's disease (AD) is a pervasive neurodegeneration disease with high heritability. In this study, we employed CRISPR‐Cas9‐engineered technology to investigate the effects of a rare mutation (rs144662445) in the A kinase anchoring protein 9 (AKAP9) gene, which is associated with AD in African Americans (AA), on tau pathology and the tau interactome in SH‐SY5Y P301L neuron‐like cells. The mutation significantly increased the level of phosphorylated tau, specifically at the site Ser396/Ser404. Moreover, analyses of the tau interactome measured by affinity purification‐mass spectrometry revealed that differentially expressed tau‐interacting proteins in AKAP9 mutant cells were associated with RNA translation, RNA localization and oxidative activity, recapitulating the tau interactome signature previously reported with human AD brain samples. Importantly, these results were further validated by functional studies showing a significant reduction in protein synthesis activity and excessive oxidative stress in AKAP9 mutant compared with wild type cells in a tau‐dependent manner, which are mirrored with pathological phenotype frequently seen in AD. Our results demonstrated specific effects of rs14462445 on mis‐processing of tau and suggest a potential role of AKAP9 in AD pathogenesis.

PO-629-02 NEW EVIDENCE TO CHALLENGE CLINGEN'S “DISPUTED EVIDENCE” DESIGNATION FOR AKAP9 AS A BONA FIDE SUSCEPTIBILITY GENE FOR CONGENITAL LONG QT SYNDROME

A-kinase-anchoring protein-9 (AKAP9) mediates the phosphorylation state of the KCNQ1-encoded Kv7.1 potassium channel. Loss-of-function (LOF) variants in KCNQ1 cause type 1 long QT syndrome (LQT1). In 2007, we published data suggesting AKAP9-S1570L as a novel LQTS-causative variant and AKAP9 as a novel LQTS-susceptibility gene. However, in a recent re-appraisal of LQTS genes, the Clinical Genome Resource (ClinGen) demoted AKAP9 to a “disputed evidence” gene due to apparent lack of sufficient evidence to support causation of LQTS. To characterize the electrophysiology of a LQTS patient-derived induced pluripotent stem cell-cardiomyocyte (iPSC-CM) AKAP9-S1570L model and its corresponding CRISPR/Cas9 gene-edited/variant-corrected isogenic control (IC). iPSC-CMs were generated from an AKAP9-S1570L positive female diagnosed with LQTS at 14 years of age with a QTc > 480 ms, history of syncope, a LQT1-suggestive treadmill stress test, and a positive family history of QT-prolongation. Standard whole-cell patch clamp technique was performed to measure the action potential duration (APD) of both the AKAP9-S1570L and IC iPSC-CMs. To determine if KCNQ1 contributes to the APD prolongation of the variant iPSC-CMs, the KCNQ1 channel specific activator, ML277 was used in additional APD measurements. APD50 (457 ± 21) and APD90 (549 ± 22 ms) were significantly prolonged in the AKAP9-S1570L iPSC-CMs compared to the IC iPSC-CMs (APD50, 335 ± 15 ms; APD90, 413 ± 16 ms; p<0.05). Addition of ML277 resulted in a greater degree of APD shortening in AKAP9-S1570L iPSC-CMs (APD50 shortening, 349 ± 40 ms (p<0.05); APD90 shortening, 397 ± 42 ms (p<0.05) than in IC iPSC-CMs (APD50 shortening, 219 ± 31 ms; APD90 shortening, 242 ± 33 ms). This indicates KCNQ1 LOF may contribute to the mechanism underlying APD prolongation in the patient-specific AKAP9-S1570L iPSC-CMs, consistent with our previously published data. Using patient specific iPSC-CMs and isogenic controls, we provide new evidence bolstering AKAP9-S1570L as the pathogenic LQTS-causative variant responsible for this patient’s LQTS. Whether ClinGen deems this sufficient evidence to rescue AKAP9 from genetic purgatory and re-classify it as a sufficient evidence LQTS-susceptibility gene, remains to be seen.

Abstract 10192: Circular RNA Formation in the Failing Heart is Enhanced by the Reduction of Adenosine-to-Inosine RNA Editing

Introduction: Adenosine-to-Inosine (A-to-I) RNA editing is a post-transcriptional modification process regulating RNA stability and alternative splicing. A-to-I RNA editing is conducted by the enzymes ADAR1 and ADAR2 and mainly targets Alu elements, primate-specific elements which have been associated with the formation of circular RNA (circRNA). Although differential expression of circRNAs has been studied in heart failure (HF), the extent of A-to-I RNA editing and consequences in the human heart remain largely unknown. Methods and Results: We analyzed RNA editing in human heart samples of HF (n=20) patients and controls (n=10) using RNA sequencing. We found a reduction of A-to-I RNA editing in intronic Alu elements of protein-coding genes in HF patients compared to controls. The majority (96%) of regulated circRNAs were upregulated. The predicted back-splice sites (BSS) of 20 circRNAs were validated by qPCR. The circRNA candidates correlated with RNA editing (R=0.47, P=0.02). Among the upregulated circRNAs, we identified two circular transcripts (circAKAP13) derived from the AKAP13 gene, which showed reduced A-to-I RNA editing in HF (-70.7%, n=20). In HF, ADAR2 was reduced (-68.2%) and ADAR1 was increased (7.41±0.13 -fold) on protein level (n=3-6). The knockdown of ADAR1 did not alter circRNA levels, whereas the knockdown of ADAR2 led to significantly upregulated levels of circAKAP13 (1.88±0.42 -fold, n=6). Consistently, ADAR2 overexpression reduced circAKAP13 expression (-41%, n=3). Using two mini-genes containing exons 15-19 of the AKAP13 gene and flanking Alu elements, we found convergent Alu elements enhancing circAKAP13 expression. Conclusion: In conclusion, these data describe the A-to-I RNA editome in the human heart for the first time. Reduced A-to-I RNA editing in HF patients is associated with elevated circRNA levels. We propose a primate-specific splicing mechanism mediated by A-to-I RNA editing in the human heart. These findings contribute to a better mechanistic understanding of A-to-I RNA editing in cardiac diseases.

Upregulated PPARG2 facilitates interaction with demethylated AKAP12 gene promoter and suppresses proliferation in prostate cancer

Prostate cancer (PCA) is one of the most common male genitourinary tumors. However, the molecular mechanisms involved in the occurrence and progression of PCA have not been fully clarified. The present study aimed to investigate the biological function and molecular mechanism of the nuclear receptor peroxisome proliferator-activated receptor gamma 2 (PPARG2) in PCA. Our results revealed that PPARG2 was downregulated in PCA, and overexpression of PPARG2 inhibited cell migration, colony formation, invasion and induced cell cycle arrest of PCA cells in vitro. In addition, PPARG2 overexpression modulated the activation of the Akt signaling pathway, as well as inhibited tumor growth in vivo. Moreover, mechanistic analysis revealed that PPARG2 overexpression induced increased expression level of miR-200b-3p, which targeted 3′ UTR of the downstream targets DNMT3A/3B, and facilitated interaction with demethylated AKAP12 gene promoter and suppressed cell proliferation in PCA. Our findings provided the first evidence for a novel PPARG2-AKAP12 axis mediated epigenetic regulatory network. The study identified a molecular mechanism involving an epigenetic modification that could be possibly targeted as an antitumoral strategy against prostate cancer.

ATP8A2 and AKAP10 Gene Mutations in a Patient with Prader-Willi Syndrome: A Case Report and Literature Review

Introduction: Prader-Willi syndrome (PWS) is an epigenetic disease. Cerebellar ataxia, mental retardation, and disequilibrium syndrome type 4 (CAMRQ4) is a genetic disorder caused by ATP8A2 gene mutation. AKAP10 gene is related to autosomal dominant cardiac conduction defect and cardiac susceptibility. Here, we report a PWS infant with ATP8A2 and AKAP10 mutations, who presented multiple dysmorphic features and review correlative literature. Case Presentation: A 3-month-old boy presented to our unit because of developmental delay after birth. He had a poor response, feeble cry, hypotonia of extremities, empty scrotum, and characteristic facial features. The whole-exome sequencing showed c.187C&gt;G (p.P63A) in exon 2 originated from his father and c.2138T&gt;C (p.I713T) in exon 23 originated from his mother, which were compound heterozygous variants of the ATP8A2 gene. A c.43delC heterozygous variant in exon 1 of the AKAP10 gene was also detected. Genetic analysis revealed normal copy numbers but abnormal methylation in the 15q11-13 region, which implied nondeletion type PWS. Conclusions: In patients with dysmorphic facial features, hypotonia and developmental delay, PWS should be considered in the differential diagnosis. Moreover, other complicated hereditary diseases should be considered in patients with PWS.

AKAP12 Expression in HER2-positive Breast Cancer and Its Clinical Significance

AKAP12 Expression in HER2-positive Breast Cancer and Its Clinical Significance

Integrative molecular characterization of Chinese prostate cancer specimens.

Prostate cancer (PCa) exhibits epidemiological and molecular heterogeneity. Despite extensive studies of its phenotypic and genetic properties in Western populations, its molecular basis is not clear in Chinese patients. To determine critical molecular characteristics and explore correlations between genomic markers and clinical parameters in Chinese populations, we applied an integrative genetic/transcriptomic assay that combines targeted next-generation sequencing and quantitative real-time PCR (qRT-PCR) on samples from 46 Chinese patients with PCa. Lysine (K)-specific methyltransferase 2D (KMT2D), zinc finger homeobox 3 (ZFHX3), A-kinase anchoring protein 9 (AKAP9), and GLI family zinc finger 1 (GLI1) were frequently mutated in our cohort. Moreover, a clinicopathological analysis showed that RB transcriptional corepressor 1 (RB1) deletion was common in patients with a high risk of disease progression. Remarkably, four genomic events, MYC proto-oncogene (MYC) amplification, RB1 deletion, APC regulator of WNT signaling pathway (APC) mutation or deletion, and cyclin-dependent kinase 12 (CDK12) mutation, were correlated with poor disease-free survival. In addition, a close link between KMT2D expression and the androgen receptor (AR) signaling pathway was observed both in our cohort and in The Cancer Genome Atlas Prostate Adenocarcinoma (TCGA-PRAD) data. In summary, our results demonstrate the feasibility and benefits of integrative molecular characterization of PCa samples in disease pathology research and personalized medicine.

Mice deficient in AKAP13 (BRX) develop compulsive-like behavior and increased body weight

ObjectiveHormonal contributions to the sex-dependent development of both obsessive-compulsive disorder (OCD) and obesity have been described, but the underlying mechanisms are incompletely understood. A-kinase anchoring protein 13 (AKAP13) significantly augments ligand-dependent activation of estrogen receptors alpha and beta. The hypothalamus and pituitary gland are implicated in the development and exacerbation of OCD and obesity and have strong AKAP13 expression. The AKAP13 localization pattern observed in these key brain regions together with its effects on sex steroid action suggest a potential role for AKAP13 in compulsive-like behaviors. Here we tested the role of AKAP13 in compulsive-like behavior and body weight using an Akap13 haploinsufficient murine model. Materials and methodsTargeted deletion of the Akap13 gene generated haploinsufficient (Akap13+/−) mice in a C57BL6/J genetic background. Established behavioral assays were conducted, video recorded, and scored blindly to assess compulsive-like behavior based on genotype and gender. Tests included: marble-burying, grooming, open- field and elevated plus-maze. Brain and body weights were also obtained. Mean levels of test outcomes were compared using multi-way ANOVA to test for genotype, sex, genotype*sex, and genotype*sex*age interaction effects with Bonferroni adjustment for multiple comparisons, to further explain any significant interactions. ResultsThe marble-burying and grooming assays revealed significant sex-dependent increases in perseverative, compulsive-like behaviors in female Akap13 haploinsufficient mice compared to female wild type (WT) mice by demonstrating increased marble-burying activity (p = .0025) and a trend towards increased grooming behavior (p = .06). Male Akap13 haploinsufficient mice exhibited no behavioral changes (p > 0.05). Elevated plus-maze and open-field test results showed no overt anxiety-like behavior in Akap13 haploinsufficient mice irrespective of sex (p > 0.05, both). No differences in brain weight were found in Akap13 haploinsufficient mice compared to WT mice (p > 0.05). However, female Akap13 haploinsufficient mice weighed more than female WT mice in the 4 to <7 months age range (p = .0051). Male Akap13 haploinsufficient mice showed no differences in weight compared to male WT mice (p = >0.05) at any age range examined. ConclusionAkap13 haploinsufficiency led to sex-dependent, compulsive-like behavioral changes in a murine model. Interestingly, Akap13 haploinsufficiency also led to a sex-dependent increase in body weight. These results revealed a requirement for AKAP13 in murine behavior, particularly in female mice, and is the first report of AKAP13 involvement in murine behavior. Future studies may examine the involvement of AKAP13 in the pathophysiology of OCD in female humans and may contribute to a better understanding of the role of AKAP13 and sex hormones in the development and exacerbation of OCD.

CRISPR‐Cas9 knock out of gravin variant 1 impairs in vitro angiogenic sprouting

Angiogenesis is a highly regulated physiological process that is controlled by several signaling pathways including Src dependent and cAMP dependent pathways. Currently, the mechanisms underlying the coordination and integration of these signaling pathways are unknown, but based on several knockdown studies, we postulate that gravin (AKAP12), which is expressed as two variants in endothelial cells, may serve as a scaffold to coordinate Src and cAMP dependent signaling during angiogenesis. To investigate this hypothesis, we are using gene editing and protein expression approaches to identify the role of each gravin variant and the role of the Src and PKA binding domains in gravin in angiogenesis. Here, we report on the effect of knocking out gravin variant 1 using CRISPR‐Cas9 on angiogenic sprouting in a 3D‐collagen gel model. Immortalized human umbilical vein endothelial cells (HUVEC‐TERT2) were transfected with a CRISPR‐Cas9 construct in which Cas9 was targeted to exon 3. An RFLP assay designed to identify changes in an HpyCH4III site at the targeted double stranded break point identified a positive clone which lacked the restriction site. Subsequent sequencing revealed a single base deletion at the targeted site in exon 3 of the AKAP12 gene. Reverse transcriptase PCR showed a partial loss of variant 1 mRNA and sequencing of the RT‐PCR product confirmed the single base deletion. Western blotting demonstrated loss of variant 1 in the CRISPR‐Cas9 modified cells while immunofluorescence microscopy using an anti‐gravin antibody that recognized the C‐terminal region of both variants revealed approximately a 50% decrease in fluorescence intensity in CRISPR‐Cas9 treated cells. This CRISPR modified cell line, expressing only variant 2 of gravin, showed altered cell morphology and behavior compared to wild type cells. When cultured on collagen gels, variant 1 knockout cultures showed significantly fewer sprouts than wild type cultures. Confocal microscopy revealed that fewer variant 1 knockout cells migrated into collagen gels, resulting in shorter sprouts with fewer branches, and that these cells displayed fewer filopodia than wild type cells. These results provide evidence that variant 1 of gravin plays a role in invasive cell migration and angiogenic sprouting, which are essential cellular events that regulate angiogenesis. Future studies will investigate the mechanism by which variant 1 contributes to angiogenic sprouting and the role that each variant of gravin plays in Src and cAMP dependent signaling in endothelial cell migration, adhesion and angiogenic sprouting.Support or Funding InformationSupported by NIH grants P30GM103329, P20GM103442 and P20GM113123This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Tau Phosphorylation is Impacted by Rare AKAP9 Mutations Associated with Alzheimer Disease in African Americans

We studied the effect of two rare mutations (rs144662445 and rs149979685) in the A-kinase anchoring protein 9 (AKAP9) gene, previously associated with Alzheimer disease (AD) in African Americans (AA), on post-translational modifications of AD-related pathogenic molecules, amyloid precursor protein (APP) and microtubule-associated protein Tau using lymphoblastoid cell lines (LCLs) from 11 AA subjects with at least one AKAP9 mutation and 17 AA subjects lacking these mutations. LCLs were transduced by viral vectors expressing causative AD mutations in APP or human full-length wild type Tau. Cell lysates were analyzed for total APP, Aβ40, and total and T181 phospho-Tau (pTau). AKAP9 mutations had no effect on Aβ40/APP, but significantly increased pTau/Tau ratio in LCLs treated with phosphodiesterase-4 inhibitor rolipram, which activates protein kinase A. Proteomic analysis of Tau interactome revealed enrichment of RNA binding proteins and decrease of proteasomal molecules in rolipram-treated cells with AKAP9 mutations. This study shows the impact of rare functional AKAP9 mutations on Tau, a central mechanism of AD pathogenesis, in LCLs derived from AD and control subjects.