A resource database for protein kinase substrate sequence-preference motifs based on large-scale mass spectrometry data

BACKGROUND

Protein phosphorylation is one of the most prevalent posttranslational modifications involved in molecular control of cellular processes, and is mediated by over 520 protein kinases in humans and other mammals. Identification of the protein kinases responsible for phosphorylation events is key to understanding signaling pathways. Unbiased phosphoproteomics experiments have generated a wealth of data that can be used to identify protein kinase targets and their preferred substrate sequences.

METHODS

This study utilized prior data from mass spectrometry-based studies identifying sites of protein phosphorylation after in vitro incubation of protein mixtures with recombinant protein kinases. PTM-Logo software was used with these data to generate position-dependent Shannon information matrices and sequence motif 'logos'. Webpages were constructed for facile access to logos for each kinase and a new stand-alone application was written in Python that uses the position-dependent Shannon information matrices to identify kinases most likely to phosphorylate a particular phosphorylation site.

RESULTS

A database of kinase substrate target preference logos allows browsing, searching, or downloading target motif data for each protein kinase ( https://esbl.nhlbi.nih.gov/Databases/Kinase_Logos/ ). These logos were combined with phylogenetic analysis of protein kinase catalytic sequences to reveal substrate preference patterns specific to particular groups of kinases ( https://esbl.nhlbi.nih.gov/Databases/Kinase_Logos/KinaseTree.html ). A stand-alone program, KinasePredictor, is provided ( https://esbl.nhlbi.nih.gov/Databases/Kinase_Logos/KinasePredictor.html ). It takes as input, amino-acid sequences surrounding a given phosphorylation site and generates a ranked list of protein kinases most likely to phosphorylate that site.

CONCLUSIONS

This study provides three new resources for protein kinase characterization. It provides a tool for prediction of kinase-substrate interactions, which in combination with other types of data (co-localization, etc.), can predict which kinases are likely responsible for a given phosphorylation event in a given tissue. Video Abstract.

Poly(ADP-ribose) polymerase-1 affects vasopressin-mediated AQP2 expression in collecting duct cells of the kidney

Poly(ADP-ribosyl)ation (PARylation), as a posttranslational modification mediated by poly(ADP-ribose) polymerases (PARPs) catalyzing the transfer of ADP-ribose from NAD+ molecules to acceptor proteins, involves a number of cellular processes. As mice lacking the PARP-1 gene (Parp1) produce more urine, we investigated the role of PARP-1, the most prevalent member of the PARP family, in the vasopressin-responsive expression of aquaporin-2 (AQP2). In biotin-conjugated nicotinamide adenine dinucleotide (biotin-NAD+) pulldown and immunoprecipitation assays of poly(ADP)-ribose in mpkCCDc14 cells, immunoblots demonstrated that 1-deamino-8-D-arginine vasopressin (dDAVP) induced the PARylation of total proteins, associated with an increase in the cleavage of PARP-1 and cleaved caspase-3 expression. By inhibiting PARP-1 with siRNA, the abundance of dDAVP-induced AQP2 mRNA and protein was significantly diminished. In contrast, despite a substantial decrease in PARylation, the PARP-1 inhibitor (PJ34) had no effect on the dDAVP-induced regulation of AQP2 expression. The findings suggest that PARP-1 protein expression itself, and not PARP-1-mediated PARylation, is necessary for dDAVP-regulated AQP2 expression. Bioinformatic analysis revealed that 408 proteins interact with PARP-1 in the collecting duct (CD) cells of the kidney. Among them, the signaling pathway of the vasopressin V2 receptor was identified for 49 proteins. In particular, β-catenin, which is phosphorylated at Ser552 by dDAVP, was identified as the PARP-1-interacting protein. A significant decrease of β-catenin phosphorylation (Ser552) in response to dDAVP was associated with siRNA-mediated PARP-1 knockdown. Taken together, PARP-1 is likely to play a role in vasopressin-induced AQP2 expression by interacting with β-catenin in renal CD cells.NEW & NOTEWORTHY The poly(ADP-ribose) polymerase (PARP) family catalyzes poly(ADP-ribosylation) (PARylation), which is one of the posttranslational modifications of largely undetermined physiological significance. This study investigated the role of PARP-1, the most prevalent member of the PARP family, in the vasopressin-responsive expression of aquaporin-2 (AQP2). The results demonstrated that PARP-1 protein expression itself, and not PARP-1-mediated PARylation, is necessary for dDAVP-regulated AQP2 expression. β-Catenin, which is phosphorylated at Ser552 by dDAVP, was identified as the PARP-1-interacting protein.

Using CRISPR-Cas9/phosphoproteomics to identify substrates of calcium/calmodulin-dependent kinase 2δ

Ca2+/Calmodulin-dependent protein kinase 2 (CAMK2) family proteins are involved in the regulation of cellular processes in a variety of tissues including brain, heart, liver, and kidney. One member, CAMK2δ (CAMK2D), has been proposed to be involved in vasopressin signaling in the renal collecting duct, which controls water excretion through regulation of the water channel aquaporin-2 (AQP2). To identify CAMK2D target proteins in renal collecting duct cells (mpkCCD), we deleted Camk2d and carried out LC-MS/MS-based quantitative phosphoproteomics. Specifically, we used CRISPR/Cas9 with two different guide RNAs targeting the CAMK2D catalytic domain to create multiple CAMK2D KO cell lines. AQP2 protein abundance was lower in the CAMK2D KO cells than in CAMK2D-intact controls. AQP2 phosphorylation at Ser256 and Ser269 (normalized for total AQP2) was decreased. However, trafficking of AQP2 to and from the apical plasma membrane was sustained. Large-scale quantitative phosphoproteomic analysis (TMT-labeling) in the presence of the vasopressin analog dDAVP (0.1 nM, 30 min) allowed quantification of 11,570 phosphosites of which 169 were significantly decreased, while 206 were increased in abundance in CAMK2D KO clones. These data are available for browsing or download at https://esbl.nhlbi.nih.gov/Databases/CAMK2D-proteome/. Motif analysis of the decreased phosphorylation sites revealed a target preference of -(R/K)-X-X-p(S/T)-X-(D/E), matching the motif identified in previous in vitro phosphorylation studies using recombinant CAMK2D. Thirty five of the significantly downregulated phosphorylation sites in CAMK2D KO cells had exactly this motif and are judged to be likely direct CAMK2D targets. This adds to the list of known CAMK2D target proteins found in prior reductionist studies.

Signaling mechanisms in renal compensatory hypertrophy revealed by multi-omics

Loss of a kidney results in compensatory growth of the remaining kidney, a phenomenon of considerable clinical importance. However, the mechanisms involved are largely unknown. Here, we use a multi-omic approach in a unilateral nephrectomy model in male mice to identify signaling processes associated with renal compensatory hypertrophy, demonstrating that the lipid-activated transcription factor peroxisome proliferator-activated receptor alpha (PPARα) is an important determinant of proximal tubule cell size and is a likely mediator of compensatory proximal tubule hypertrophy.

Low-Loss Pogo Pin Probe Card with a Coupling Isolation Structure up to 50 GHz

A design for a millimeter wave RF probe card that removes resonance is proposed. The designed probe card optimizes the position of the ground surface and the signal pogo pins to resolve the resonance and signal loss issues that occur when connecting a dielectric socket and a PCB. At millimeter wave frequencies, the height of the dielectric socket and pogo pin matches the length of half a wavelength, allowing the socket to act as a resonator. When the leakage signal from the PCB line is coupled to the 2.9 mm high socket with pogo pins, resonance at a frequency of 28 GHz is generated. The probe card uses the ground plane as a shielding structure to minimize this resonance and radiation loss. The importance of the signal pin location is verified via measurements in order to address the discontinuity caused by field polarity switching. A probe card fabricated using the proposed technique exhibits an insertion loss performance of -8 dB up to 50 GHz and eliminates resonance. A signal with an insertion loss of -3.1 dB can be transmitted to a system-on-chip in a practical chip test.

Circadian gene expression in mouse renal proximal tubule

Circadian variability in kidney function is well recognized but is often ignored as a potential confounding variable in physiological experiments. Here, we have created a data resource consisting of expression levels for mRNA transcripts in microdissected proximal tubule segments from mice as a function of the time of day. Small-sample RNA sequencing was applied to microdissected S1 proximal convoluted tubules and S2 proximal straight tubules. After stringent filtering, the data were analyzed using JTK-Cycle to detect periodicity. The data set is provided as a user-friendly webpage at https://esbl.nhlbi.nih.gov/Databases/Circadian-Prox2/. In proximal convoluted tubules, 234 transcripts varied in a circadian manner (4.0% of the total). In proximal straight tubules, 334 transcripts varied in a circadian manner (5.3%). Transcripts previously known to be associated with corticosteroid action and with increased flow were found to be overrepresented among circadian transcripts peaking during the "dark" portion of the day [zeitgeber time (ZT)14-22], corresponding to peak levels of corticosterone and glomerular filtration rate in mice. To ask whether there is a time-of-day dependence of protein abundances in the kidney, we carried out LC-MS/MS-based proteomics in whole mouse kidneys at ZT12 and ZT0. The full data set (n = 6,546 proteins) is available at https://esbl.nhlbi.nih.gov/Databases/Circadian-Proteome/. Overall, 293 proteins were differentially expressed between ZT12 and ZT0 (197 proteins greater at ZT12 and 96 proteins greater at ZT0). Among the regulated proteins, only nine proteins were found to be periodic in the RNA-sequencing analysis, suggesting a high level of posttranscriptional regulation of protein abundances.NEW & NOTEWORTHY Circadian variation in gene expression can be an important determinant in the regulation of kidney function. The authors used RNA-sequencing transcriptomics and LC-MS/MS-based proteomics to identify gene products expressed in a periodic manner. The data were used to construct user-friendly web resources.

Data resource: vasopressin-regulated protein phosphorylation sites in the collecting duct

Vasopressin controls renal water excretion through actions to regulate aquaporin-2 (AQP2) trafficking, transcription, and degradation. These actions are in part dependent on vasopressin-induced phosphorylation changes in collecting duct cells. Although most efforts have focused on the phosphorylation of AQP2 itself, phosphoproteomic studies have identified many vasopressin-regulated phosphorylation sites in proteins other than AQP2. The goal of this bioinformatics-based review is to create a compendium of vasopressin-regulated phosphorylation sites with a focus on those that are seen in both native rat inner medullary collecting ducts and cultured collecting duct cells from the mouse (mpkCCD), arguing that these sites are the best candidates for roles in AQP2 regulation. This analysis identified 51 vasopressin-regulated phosphorylation sites in 45 proteins. We provide resource web pages at https://esbl.nhlbi.nih.gov/Databases/AVP-Phos/ and https://esbl.nhlbi.nih.gov/AVP-Network/, listing the phosphorylation sites and describing annotated functions of each of the vasopressin-targeted phosphoproteins. Among these sites are 23 consensus protein kinase A (PKA) sites that are increased in response to vasopressin, consistent with a central role for PKA in vasopressin signaling. The remaining sites are predicted to be phosphorylated by other kinases, most notably ERK1/2, which accounts for decreased phosphorylation at sites with a X-p(S/T)-P-X motif. Additional protein kinases that undergo vasopressin-induced changes in phosphorylation are Camkk2, Cdk18, Erbb3, Mink1, and Src, which also may be activated directly or indirectly by PKA. The regulated phosphoproteins are mapped to processes that hypothetically can account for vasopressin-mediated control of AQP2 trafficking, cytoskeletal alterations, and Aqp2 gene expression, providing grist for future studies.NEW & NOTEWORTHY Vasopressin regulates renal water excretion through control of the aquaporin-2 water channel in collecting duct cells. Studies of vasopressin-induced protein phosphorylation have focused mainly on the phosphorylation of aquaporin-2. This study describes 44 phosphoproteins other than aquaporin-2 that undergo vasopressin-mediated phosphorylation changes and summarizes potential physiological roles of each.

Proteomics and AQP2 regulation

The advent of modern quantitative protein mass spectrometry techniques around the turn of the 21st century has contributed to a revolution in biology referred to as 'systems biology'. These methods allow identification and quantification of thousands of proteins in a biological specimen, as well as detection and quantification of post-translational protein modifications including phosphorylation. Here, we discuss these methodologies and show how they can be applied to understand the effects of the peptide hormone vasopressin to regulate the molecular water channel aquaporin-2. The emerging picture provides a detailed framework for understanding the molecular mechanisms involved in water balance disorders.

Bayesian analysis of dynamic phosphoproteomic data identifies protein kinases mediating GPCR responses

Background

A major goal in the discovery of cellular signaling networks is to identify regulated phosphorylation sites (“phosphosites”) and map them to the responsible protein kinases. The V2 vasopressin receptor is a G-protein coupled receptor (GPCR) that is responsible for regulation of renal water excretion through control of aquaporin-2-mediated osmotic water transport in kidney collecting duct cells. Genome editing experiments have demonstrated that virtually all vasopressin-triggered phosphorylation changes are dependent on protein kinase A (PKA), but events downstream from PKA are still obscure.

Methods

Here, we used: 1) Tandem mass tag-based quantitative phosphoproteomics to experimentally track phosphorylation changes over time in native collecting ducts isolated from rat kidneys; 2) a clustering algorithm to classify time course data based on abundance changes and the amino acid sequences surrounding the phosphosites; and 3) Bayes’ Theorem to integrate the dynamic phosphorylation data with multiple prior “omic” data sets covering expression, subcellular location, known kinase activity, and characteristic surrounding sequences to identify a set of protein kinases that are regulated secondary to PKA activation.

Results

Phosphoproteomic studies revealed 185 phosphosites regulated by vasopressin over 15 min. The resulting groups from the cluster algorithm were integrated with Bayes’ Theorem to produce corresponding ranked lists of kinases likely responsible for each group. The top kinases establish three PKA-dependent protein kinase modules whose regulation mediate the physiological effects of vasopressin at a cellular level. The three modules are 1) a pathway involving several Rho/Rac/Cdc42-dependent protein kinases that control actin cytoskeleton dynamics; 2) mitogen-activated protein kinase and cyclin-dependent kinase pathways that control cell proliferation; and 3) calcium/calmodulin-dependent signaling.

Conclusions

Our findings identify a novel set of downstream small GTPase effectors and calcium/calmodulin-dependent kinases with potential roles in the regulation of water permeability through actin cytoskeleton rearrangement and aquaporin-2 trafficking. The proposed signaling network provides a stronger hypothesis for the kinases mediating V2 vasopressin receptor responses, encouraging future targeted examination via reductionist approaches. Furthermore, the Bayesian analysis described here provides a template for investigating signaling via other biological systems and GPCRs.

AB1279 POOR QUALITY OF LIFE AND REDUCED WORK PRODUCTIVITY IN EUROPEAN PATIENTS WITH DERMATOMYOSITIS AND POLYMYOSITIS: FINDINGS FROM A SYSTEMATIC LITERATURE REVIEW

Background

Dermatomyositis (DM) and polymyositis (PM) are rare heterogenous systemic autoimmune disorders of the skin, muscles, and other organs with few effective treatment options available. They are described as devastating diseases but the full impact on patients’ lives in Europe is not well understood.

Objectives

To systematically review and summarize evidence on humanistic burden of disease in patients with DM and PM in Europe to better understand patient-relevant aspects of disease and key domains of life impacted by DM and PM in the European setting.

Methods

A systematic literature review (SLR) was conducted in MEDLINE and Embase databases to identify studies in children and adults with DM and PM, published in the English language between Jan 1, 2011, and Apr 28, 2021. Only primary studies enrolling 10 or more patients were included, irrespective of country or region. Each eligible article was independently reviewed by two reviewers. The title and study abstracts were reviewed to assess eligibility for full-text review. The topics of interest were clinical, humanistic, and economic burden of disease, as well as current management and unmet needs in DM and PM. Information on geographic scope was extracted from the papers of included studies. The current abstract summarizes SLR results on humanistic burden of DM and PM in European patients.

Results

A total of 2,967 non-duplicated publications were retrieved from medical databases and analyzed against pre-defined study selection criteria. There were 2,574 records excluded at title and abstract screening. Remaining 393 records were analyzed in the full text with 208 papers considered relevant. Additional 21 papers were identified from searching reference list of relevant studies and conference proceedings. In total, 222 studies described in 229 publications were included in data abstraction. Among 43 studies conducted across 14 European countries, 12 studies evaluated health-related quality of life (HRQoL) and work productivity in patients with DM and PM. In 6 studies, patients received standard of care therapy. Six studies enrolled adults with DM and PM and 6 were conducted in patients with juvenile onset of DM. There were 6 cross-sectional analyses, 4 longitudinal cohort studies, 2 case-control studies, with sample size ranging from 11 to 246 patients. Adults with DM and PM had significantly worse HRQoL across multiple domains of 36-Item Short Form Survey (SF-36) compared to controls from general population, with a strong negative impact of muscle weakness on physical functioning. Patients reported high difficulties in performing leisure time activities, moving around and work as indicated by median scores of 4-5 points in a 7-point Myositis Activity Profile (MAP). Reduced grip force in DM and PM adults was significantly associated with worse performance in domestic activities in the MAP assessment (p<0.05). In women with DM and PM, poor grip force additionally impacted vitality and mental health as measured by SF-36 (p<0.05). There were no associations between grip force and any SF-36 domain in men. Approximately 60% of adult patients rated their ability to work as “poor” or “less good” according to the Work Ability Index, 68% of patients had more than one week of sick leave in the past year, and 20.8% of them were permanently not able to work for at least 2 years. Children and adolescents with DM had impaired physical and psychosocial functioning compared to healthy norms with 40% of individuals showing increased emotional distress requiring in-depth psychological assessment.

Conclusion

European patients with DM and PM experience a muscle weakness that has a detrimental impact on HRQoL, daily activities and ability to work. Similar disease impact on HRQoL was reported in patients in North America. These findings suggest a need for a novel therapy that will restore physical functioning in patients with DM and PM.

Disclosure of Interests

Jens Schmidt Speakers bureau: Euroimmun, CSL Behring, Consultant of: Alnylam, Argenx, Biotest, CSL Behring, Kezar Life Sciences, LFB, Novartis, Octapharma, UCB, Grant/research support from: CSL Behring, Novartis, Konrad Pisarczyk Consultant of: Kezar Life Sciences, Richard Leff Shareholder of: Kezar Life Sciences, Consultant of: Kezar Life Sciences, Kiruthi Palaniswamy Shareholder of: Kezar Life Sciences, Employee of: Kezar Life Sciences, Eunmi Park Shareholder of: Kezar Life Sciences, Employee of: Kezar Life Sciences, Li Long Shareholder of: Kezar Life Sciences, Employee of: Kezar Life Sciences

AB1277 POOR LONG-TERM OUTCOMES AND SUBSTANTIAL BURDEN OF COMORBIDITIES IN EUROPEAN PATIENTS WITH DERMATOMYOSITIS/POLYMYOSITIS: RESULTS FROM A SYSTEMATIC LITERATURE REVIEW

Background

Dermatomyositis (DM) and polymyositis (PM) are rare heterogenous systemic autoimmune disorders of the skin, muscles and other organs that may have a devastating impact on patients’ lives. Despite various therapies used in clinical practice, a notable proportion of patients seem not to achieve sustainable remission. There is a need to better understand long-term outcomes and comorbidities in patients with DM/PM in Europe.

Objectives

To systematically review and summarize evidence on clinical burden of disease in patients with DM/PM in Europe.

Methods

A systematic literature review (SLR) was conducted in MEDLINE and Embase databases to identify studies in children and adults with DM/PM, published in the English language between 2011 and 2021. Primary studies enrolling 10 or more patients were included, irrespective of country or region. Each eligible article was independently reviewed by two reviewers. The title and study abstracts were reviewed to assess eligibility for full-text review. The current abstract summarizes SLR results on the long-term outcomes and comorbidities in patients with DM/PM in Europe.

Results

A total of 2,967 non-duplicated publications were retrieved from medical databases and analyzed against pre-defined study selection criteria. There were 2,574 records excluded at title and abstract screening. Remaining 393 records were analyzed in the full text with 208 papers considered relevant. Additional 21 papers were identified from searching reference list of relevant studies and conference proceedings. In total, 222 studies (229 publications) were included in data abstraction. Among 43 studies conducted across 14 European countries, 23 studies evaluated long-term outcomes of disease and burden of comorbidities. There were 14 longitudinal cohort studies, 7 cross-sectional analyses and 2 case-control studies. Only 29-44% of DM/PM adults achieved remission. Between 38% and 62% of adults with DM/PM required at least 3 different medications, suggesting inadequate response to initial and subsequent regimens. During a mean follow-up of 13.9 years, 69% patients with JDM had polycyclic or chronic disease characterized by periods of remission and recurrence or by permanently active disease for more than 2 years after diagnosis. A notable proportion of children (60.4%) showed evidence of damage in at least one body organ and 13-20% of patients had complications such as calcinosis, lipodystrophy, or muscle atrophy. Adults with DM/PM often suffered from interstitial lung disease (16-66%), serious infections leading to hospitalization or death (21-26.7%), and cardiovascular disorders (CVDs) (19-71%). Compared to age and gender matched controls without DM, patients with DM had 16-times higher risk of venous thromboembolism (HR=16.44, 95% CI: 7.54-35.86). Incidence of coronary heart disease, hemorrhagic stroke, or ischemic stroke during 10-year follow-up was approximately 1.5- to 2-times higher in DM/PM adults relative to general population. Multiple studies reported high rates of any malignancy in DM adults (7.5-33%) and in PM adults (8-11.7%). During approximately 24,000 patient-years of follow-up, adults with DM/PM had more than 4-times higher incidence of lung cancer compared to general population that also was one of the highest incidences among multiple other autoimmune diseases. Long-term prognosis in DM/PM was poor with 20-year survival below 70%. The most common causes of deaths were pulmonary-related, malignancies, and cardiac complications. Mortality due to lung cancer was more than 4-times higher than in general population (standardized mortality ratio=4.17, 95% CI: 3.03-5.60).

Conclusion

European patients with DM/PM suffer from substantial burden of comorbidities including serious infections, malignancies and CVDs that lead to poor long-term outcomes. A notable proportion of adult and juvenile patients do not achieve sustainable remission or experience relapse indicating high unmet need.

Disclosure of Interests

Jiří Vencovský Speakers bureau: Abbvie, Biogen, Boehringer, Eli Lilly, Gilead, MSD, Novartis, Pfizer, Roche, Sanofi, UCB, Werfen, Consultant of: Abbvie, Argenx, Boehringer, Eli Lilly, Gilead, Octapharma, Pfizer, UCB, Grant/research support from: Abbvie, Konrad Pisarczyk Consultant of: Kezar Life Sciences, Richard Leff Shareholder of: Kezar Life Sciences, Consultant of: Kezar Life Sciences, Eunmi Park Shareholder of: Kezar Life Sciences, Employee of: Kezar Life Sciences, Kiruthi Palaniswamy Shareholder of: Kezar Life Sciences, Employee of: Kezar Life Sciences, Li Long Shareholder of: Kezar Life Sciences, Employee of: Kezar Life Sciences.

Systems Biology of the Vasopressin V2 Receptor: New Tools for Discovery of Molecular Actions of a GPCR

Systems biology can be defined as the study of a biological process in which all of the relevant components are investigated together in parallel to discover the mechanism. Although the approach is not new, it has come to the forefront as a result of genome sequencing projects completed in the first few years of the current century. It has elements of large-scale data acquisition (chiefly next-generation sequencing-based methods and protein mass spectrometry) and large-scale data analysis (big data integration and Bayesian modeling). Here we discuss these methodologies and show how they can be applied to understand the downstream effects of GPCR signaling, specifically looking at how the neurohypophyseal peptide hormone vasopressin, working through the V2 receptor and PKA activation, regulates the water channel aquaporin-2. The emerging picture provides a detailedframework for understanding the molecular mechanisms involved in water balance disorders, pointing the way to improved treatment of both polyuric disorders and water-retention disorders causing dilutional hyponatremia.

"ADPKD-omics": determinants of cyclic AMP levels in renal epithelial cells

The regulation of cyclic adenosine monophosphate (cAMP) levels in kidney epithelial cells is important in at least 2 groups of disorders, namely water balance disorders and autosomal dominant polycystic kidney disease. Focusing on the latter, we review genes that code for proteins that are determinants of cAMP levels in cells. We identify which of these determinants are expressed in the 14 kidney tubule segments using recently published RNA-sequencing and protein mass spectrometry data ("autosomal dominant polycystic kidney disease-omics"). This includes G protein-coupled receptors, adenylyl cyclases, cyclic nucleotide phosphodiesterases, cAMP transporters, cAMP-binding proteins, regulator of G protein-signaling proteins, G protein-coupled receptor kinases, arrestins, calcium transporters, and calcium-binding proteins. In addition, compartmentalized cAMP signaling in the primary cilium is discussed, and a specialized database of the proteome of the primary cilium of cultured "IMCD3" cells is provided as an online resource (https://esbl.nhlbi.nih.gov/Databases/CiliumProteome/). Overall, this article provides a general resource in the form of a curated list of proteins likely to play roles in determination of cAMP levels in kidney epithelial cells and, therefore, likely to be determinants of progression of autosomal dominant polycystic kidney disease.

Development of postbiotics by whey bioconversion with Enterococcus faecalis M157 KACC81148BP and Lactococcus lactis CAU2013 KACC81152BP for treating periodontal disease and improving gut health

This study developed postbiotics with whey bioconversion product produced by Enterococcus faecalis M157 KACC 81148BP, and mixed whey bioconversion products produced by E. faecalis M157 KACC 81148BP and Lactococcus lactis ssp. lactis CAU2013 KACC 81152BP to alleviate periodontitis (PD) and to improve gut health. The powdered whey bioconversion product (EF) produced by E. faecalis M157 KACC 81148BP, mixed whey bioconversion products (EF+LL) from E. faecalis M157 KACC 81148BP and L. lactis CAU2013 KACC 81152BP, and phosphate-buffered saline (PBS; control) were administered orally to PD-induced rats for 8 wk. Infiltration of inflammatory cells and epithelial proliferation in periodontal tissue were found in control, but the lesions were reduced in PD+EF group (administration of EF to PD-induced rats), and no lesions were observed in PD+EF+LL group (administration of EF+LL to PD-induced rats). The bone loss volumes in PD+EF and PD+EF+LL groups were lower than in control. Cytokine production levels related to inflammation were lower and antioxidative stress markers were higher in PD+EF and PD+EF+LL groups than in control for both periodontal tissue and gut. The ratios of Lactobacillus spp. in gut microbiome of PD+EF and PD+EF+LL groups were higher than in control. These results indicate that the whey bioconversion product produced by E. faecalis M157 KACC 81148BP, and mixed whey bioconversion products produced by E. faecalis M157 KACC 81148BP and L. lactis CAU2013 KACC 81152BP are effective on relieving periodontitis and improving the gut health.

P–205 Epothilone D as an actin cytoskeleton stabilizer improved mitochondria bioenergenesis and blastocyst formation of mouse preimplantation embryo

Study question

What is primary factor of bioenergetics product activity between microtubule instability and the functional activity of mitochondria in embryo?

Summary answer

The actin cytoskeleton instability is presumably the primary cause for the bioenergenesis of mitochondrial function to the preimplantation embryo development.

What is known already

Mitochondria are cellular organelles dynamically moving and morphological changes. It provides for homeostatic energy to the cell. The dynamic property of the mitochondria is associated with the microtubule network in the cell. However, the stability of the microtubule was clearly identified for preimplantation embryo development.

Study design, size, duration

This study is designed to assess the ATP productivity of the mitochondria, and specifically to observe what its primary factor is in terms of providing microtubule stability in mammalian cells. Additionally, we investigated the relationship between blastocyst formation and actin cytoskeleton stabilization by EpD with 2-cell mice.

Participants/materials, setting, methods

We prepared the microtubule stability regulation model with the HEK293 cell line by using the microtubule stabilizer as an Epothilone D (EpD). Then we analyzed the metabolic activity of the cells through oxidative phosphorylation (OXP) ratios analysis. Also, we performed confocal live imaging to observe mitochondria morphology depending on the cells’ microtubule. Next, we treated EpD to 2-cell culture media for the analysis of blastocyst development ratios.

Main results and the role of chance

EpD significantly increased fusion form. Also, EpD enhance bioenergy ratios like OXP in the mitochondria and functional activity related marker, like mTOR compared with the control. These results suggest that microtubule stabilization enhances mitochondrial metabolism by increasing oxygen consumption. Also, EpD in 2-cell culture media led to a significant increase in the speed of development and 50% higher hatched out blastocyst formation ratios compared to the control group.

Limitations, reasons for caution

This study had limited animal experiments. For the next study, we are planning with an aim to improve the quality and development ratios of human embryos by EpD.

Wider implications of the findings: Microtubule stabilizer has a possibility to recover the mitochondria’s functional activity in the preimplantation embryo development. Mitochondrial functional activity along the actin cytoskeleton may play a pivotal role in determining the embryo quality and development ratios for archive pregnancy.

Trial registration number

non-clinical trials

Bayesian identification of candidate transcription factors for the regulation of Aqp2 gene expression

Aquaporin-2 (Aqp2) gene transcription is strongly regulated by vasopressin in the renal collecting duct. However, the transcription factors (TFs) responsible for the regulation of expression of Aqp2 remain largely unknown. We used Bayes' theorem to integrate several -omics data sets to stratify the 1,344 TFs present in the mouse genome with regard to probabilities of regulating Aqp2 gene transcription. Also, we carried out new RNA sequencing experiments mapping the time course of vasopressin-induced changes in the transcriptome of mpkCCD cells to identify TFs that change in tandem with Aqp2. The analysis identified 17 of 1,344 TFs that are most likely to be involved in the regulation of Aqp2 gene transcription. These TFs included eight that have been proposed in prior studies to play a role in Aqp2 regulation, viz., Cebpb, Elf1, Elf3, Ets1, Jun, Junb, Nfkb1, and Sp1. The remaining nine represent new candidates for future studies (Atf1, Irf3, Klf5, Klf6, Mef2d, Nfyb, Nr2f6, Stat3, and Nr4a1). Conspicuously absent is CREB (Creb1), which has been widely proposed to mediate vasopressin-induced regulation of Aqp2 gene transcription (Nielsen S, Frokiaer J, Marples D, Kwon TH, Agre P, Knepper MA. Physiol Rev 82: 205-244, 2002; Kortenoeven ML, Fenton RA. Biochim Biophys Acta 1840: 1533-1549, 2014; Bockenhauer D, Bichet DG. Nat Rev Nephrol 11: 576-588, 2015; Pearce D, Soundararajan R, Trimpert C, Kashlan OB, Deen PM, Kohan DE. Clin J Am Soc Nephrol 10: 135-146, 2015). Instead, another CREB-like TF, Atf1, ranked fourth among all TFs. RNA sequencing time-course experiments showed a rapid increase in Aqp2 mRNA, within 3 h of vasopressin exposure. This response was matched by an equally rapid increase in the abundance of the mRNA coding for Cebpb, which we have shown by chromatin immunoprecipitation-sequencing studies to bind downstream from the Aqp2 gene. The identified TFs provide a roadmap for future studies to understand regulation of Aqp2 gene expression.NEW & NOTEWORTHY Abetted by the advent of systems biology-based ("-omics") techniques in the 21st century, there has been a massive expansion of published data relevant to virtually every physiological question. The authors have developed a large-scale data integration approach based on the application of Bayes'' theorem. In the current work, they integrated 12 different -omics data sets to identify the transcription factors most likely to mediate vasopressin-dependent regulation of transcription of the aquaporin-2 gene.

Fermented milk with Lactobacillus curvatus SMFM2016-NK alleviates periodontal and gut inflammation, and alters oral and gut microbiota

This study aimed to analyze the effect of milk fermented with Lactobacillus curvatus SMFM2016-NK on periodontal diseases and gut health in a rat model. To improve the effect of Lb. curvatus SMFM2016-NK-fermented milk administration for relieving periodontitis, the periodontitis rat models were treated with the following for 4 wk: 10% skim milk (normal), periodontitis + 10% skim milk (negative control), periodontitis + Lactobacillus rhamnosus GG-fermented milk (positive control), and periodontitis + Lb. curvatus SMFM2016-NK-fermented milk (PD+LCFM). Transcriptional analysis of inflammatory cytokines [tumor necrosis factor α (TNF-α), IL-1β, IL-6, and IL-10] was performed via quantitative reverse-transcription PCR. The changes in the oral and gut microbiomes after administering Lb. curvatus SMFM2016-NK-fermented milk were analyzed with metagenomics sequencing using DNA extracted from the oral gingival tissues and feces from the cecum of the rat models. After treatment with Lb. curvatus SMFM2016-NK-fermented milk, the relative gene expression levels of TNFA and IL1B in the gingiva decreased in the PD+LCFM group compared with those in the negative control group. In the oral microbiome, the proportion of the phylum Proteobacteria in the PD+LCFM group was lower than that in the negative control after treatment with Lb. curvatus SMFM2016-NK-fermented milk. For the effect in the gut, the relative gene expression levels of inflammatory cytokines in the colon between the normal and negative control groups were not different; however, the expression levels of TNFA and IL1B in the PD+LCFM and positive control groups, respectively, were lower than those in the negative control group. The composition and diversity of the gut microbiome differed among normal, periodontitis, and Lb. curvatus SMFM2016-NK-fermented milk treatment groups. These results indicate that Lb. curvatus SMFM2016-NK-fermented milk could alleviate periodontal and gut inflammation and change oral and gut microbiota.

Phosphoproteomic identification of vasopressin-regulated protein kinases in collecting duct cells

BACKGROUND AND PURPOSE

The peptide hormone vasopressin regulates water transport in the renal collecting duct largely via the V₂ receptor, which triggers a cAMP-mediated activation of a PKA-dependent signalling network. The protein kinases downstream from PKA have not been fully identified or mapped to regulated phosphoproteins.

EXPERIMENTAL APPROACH

We carried out systems-level analysis of large-scale phosphoproteomic data quantifying vasopressin-induced changes in phosphorylation in aquaporin-2-expressing cultured collecting duct (mpkCCD) cells. Quantification was done using stable isotope labelling (SILAC method).

KEY RESULTS

Six hundred forty phosphopeptides were quantified. Stringent statistical analysis identified significant changes in response to vasopressin in 429 of these phosphopeptides. The corresponding phosphoproteins were mapped to known vasopressin-regulated cellular processes. The vasopressin-regulated sites were classified according to the sequences surrounding the phosphorylated amino acids giving 11 groups. Among the vasopressin-regulated phosphoproteins were 25 distinct protein kinases. Among these, six plus PKA appeared to account for phosphorylation of about 81% of the 313 vasopressin-regulated phosphorylation sites. The six downstream kinases were salt-inducible kinase 2 (Sik2), cyclin-dependent kinase 18 (Cdk18), calmodulin-dependent kinase kinase 2 (Camkk2), protein kinase D2 (Prkd2), mitogen-activated kinase 3 (Mapk3) and myosin light chain kinase (Mylk).

CONCLUSION AND IMPLICATIONS

In V₂ receptor-mediated signalling, PKA is at the head of a complex network that includes at least six downstream vasopressin-regulated protein kinases that are prime targets for future study. The extensive phosphoproteomic data reported in this study are provided as a web-based data resource for future studies of GPCRs.

Protein kinase A catalytic-α and catalytic-β proteins have nonredundant regulatory functions

Vasopressin regulates osmotic water transport in the renal collecting duct by protein kinase A (PKA)-mediated control of the water channel aquaporin-2 (AQP2). Collecting duct principal cells express two seemingly redundant PKA catalytic subunits, PKA catalytic α (PKA-Cα) and PKA catalytic β (PKA-Cβ). To identify the roles of these two protein kinases, we carried out deep phosphoproteomic analysis in cultured mpkCCD cells in which either PKA-Cα or PKA-Cβ was deleted using CRISPR-Cas9-based genome editing. Controls were cells carried through the genome editing procedure but without deletion of PKA. TMT mass tagging was used for protein mass spectrometric quantification. Of the 4,635 phosphopeptides that were quantified, 67 phosphopeptides were significantly altered in abundance with PKA-Cα deletion, whereas 21 phosphopeptides were significantly altered in abundance with PKA-Cβ deletion. However, only four sites were changed in both. The target proteins identified in PKA-Cα-null cells were largely associated with cell membranes and membrane vesicles, whereas target proteins in PKA-Cβ-null cells were largely associated with the actin cytoskeleton and cell junctions. In contrast, in vitro incubation of mpkCCD proteins with recombinant PKA-Cα and PKA-Cβ resulted in virtually identical phosphorylation changes. In addition, analysis of total protein abundances in in vivo samples showed that PKA-Cα deletion resulted in a near disappearance of AQP2 protein, whereas PKA-Cβ deletion did not decrease AQP2 abundance. We conclude that PKA-Cα and PKA-Cβ serve substantially different regulatory functions in renal collecting duct cells and that differences in phosphorylation targets may be due to differences in protein interactions, e.g., mediated by A-kinase anchor proteins, C-kinase anchoring proteins, or PDZ binding.

Neurological involvement and MRI brain findings in an adult with hemolytic uremic syndrome: A case report

Hemolytic uremic syndrome is a frequent complication of shiga toxin producing Escherichia coli in pediatric population. It rarely affects adults with extremely rare neurological manifestation. We present a case of hemolytic uremic syndrome in a 64-year-old male who presented with a bloody diarrhea 30 minutes after eating an expired meat sandwich. Shiga-toxin producing Escherichia coli O157:H7 was confirmed as the causative agent. The patient developed neurological manifestations with persistent encephalopathy that ultimately leads to his death after 22 days of hospitalization. Magnetic resonance imaging findings was significant for signal changes in the thalami, tectum, insulae, and central pons, impressive of hemolytic uremic syndrome.

0268 Development of an Integrated Model of Sleep Deprivation in Adolescence

Introduction

Sleep deprivation is a consistently and widely concerning problem among adolescents. Although a few models have been proposed to explain the relationships and pathways through which factors influence sleep in adolescents, there are lack of theoretical models that apply both biological and behavioral factors that contribute to sleep deprivation across the trajectory of adolescent development. The current study proposes an integrated model that draws upon constructs from several influential theories with an aim to re-conceptualize factors associated with sleep deprivation as a chronic and cyclic problem that emerges from biological and behavioral changes in youth.

Methods

The Two Process Model of Sleep Regulation, Spielman’s 3p model, the theory of planned behavior, dual systems model, and sleep health framework are used to develop an integrated model of factors that lead to sleep deprivation in adolescents.

Results

The resulting integrated model highlights the importance of adolescent’s inherent nature of delayed sleep phase at pubertal onset (two process model); increased reward-seeking that precedes the structural maturation of their cognitive control and emotions (dual systems model); and their attitudes/perceptions towards sleep (theory of planned behavior), which is often geared toward not prioritizing sleep. Sleep health framework adequately frames the pattern of sleep-wakefulness in adolescents using a multidimensional approach of sleep. Moreover, the new model presents contextual factors (Spielman’s 3p model) and the way that these constructs interact in order to maintain a vicious cycle of insufficient sleep which leads to chronic sleep deprivation.

Conclusion

The current model portrays a wide-ranging view of mechanisms underlying sleep deprivation among adolescence by integrating both biological and behavioral aspects. The model is proposed to encourage researchers to explore these conceptual elements of biological and neurobiological changes, and behavioral problems in order to operationalize relevant measures to relate the concepts to sleep deprivation and subsequent health outcomes in adolescents.

Support

None

A new treatment for presumed corneal epithelial inclusion cyst in a shih-tzu dog

An 8-year-old female shih-tzu was assessed for a 3-year history of yellow intrastromal material in the right eye. Slit-lamp biomicroscopy showed a yellow lesion in the upper half of the cornea, superficial corneal neovascularisation and oedema with negative fluorescein staining in the right eye. Ultrasound biomicroscopy revealed a nearly anechoic cystic space surrounded by hyperechoic oedematous cornea separating the stroma at three-quarters of the corneal depth. Two partial-thickness corneal incisions were performed around the lesion under topical anaesthesia. After cytology and culture sampling, intrastromal flushing was performed. A yellow viscous necrotic tissue was identified with no microorganism or evidence of tumour formation. Antibiotics, anti-inflammatories and a bandage contact lens were applied. Ultrasound biomicroscopy confirmed no recurrence 8 days later. Corneal neovascularisation and oedema gradually resolved through a 2-week follow-up. There was no recurrence in the subsequent 8 months.

Proactive text messaging (GetReady2Quit) and nicotine replacement therapy to promote smoking cessation among smokers in primary care: A pilot randomized trial protocol

INTRODUCTION

Most smokers see a physician each year, but few use any assistance when they try to quit. Text messaging programs improve smoking cessation in community and school settings; however, their efficacy in a primary care setting is unclear. The current trial assesses the feasibility and preliminary clinical outcomes of text messaging and mailed nicotine replacement therapy (NRT) among smokers in primary care.

METHODS

In this single-center pilot randomized trial, eligible smokers in primary care are offered brief advice by phone and randomly assigned to one of four interventions: (1) Brief advice only, (2) text messages targeted to primary care patients and tailored to quit readiness, (3) a 2-week supply of nicotine patches and/or lozenges (NRT), and (4) both text messaging and NRT. Randomization is stratified by practice and intention to quit. The text messages (up to 5/day) encourage those not ready to quit to practice a quit attempt, assist those with a quit date through a quit attempt, and promote NRT use. The 2-week supply of NRT is mailed to patients' homes.

RESULTS

Feasibility outcomes include recruitment rates, study retention, and treatment adherence. Clinical outcomes are assessed at 1, 2, 6, and 12-weeks post-enrollment. The primary outcome is ≥1self-reported quit attempt(s). Secondary clinical outcomes include self-reported past 7- and 30-day abstinence, days not smoked, NRT adherence, and exhaled carbon monoxide.

CONCLUSIONS

This pilot assesses text messaging plus NRT, as a proactively offered intervention for smoking cessation support in smokers receiving primary care and will inform full-scale randomized trial planning.

TRIAL REGISTRATION

ClinicalTrials.govNCT03174158.

A Longitudinal Follow-up Study on Factors Associated With Smoking Relapse Among Adolescent Quitline Users in Korea

Background: Smoking among adolescent is one of the biggest alarming issues in tobacco control. Although smoking cessation interventions for adolescents have been implemented, 92% would be relapsed within one year. However, the information on factors associated with smoking relapse is insufficient among adolescents, although it looks necessary for understanding smoking behaviors of adolescents and applying more effective intervention program for them. Korea is one of the country having the highest adolescent smoking prevalence (9.6% in boys and 2.7% in girls aged 19 years or less) and in lack of information on smoking behaviors and factors associated with relapse or successful quit. Telephone-based cessation service (hereafter Quitline) has been available since 2006 regarding the confidentiality and accessibility of adolescent smokers and it has followed-up abstinence of users with intensive counseling for 1 year. Therefore, analysis on the adolescent smokers who used Quitline might be meaningful to understand adolescents' cessation behaviors and factors associated with. Aim: To identify the factors associated with smoking relapse among adolescent Quitline users in Korea. Methods: 2141 (1370 boys and 394 girls) adolescent smokers who registered at Quitline in Korea from January 2007 to December 2017 and attempted quit were included in the current study. The baseline information on sociodemographic characteristics, smoking and other health behaviors, nicotine dependency, and motivational factors for quit were collected. Cessation outcome and reason of relapse were identified during the 1 year follow-up of each individual. Multivariate logistic regression was performed to identify associated factors of smoking relapse. Results: The analysis on the data are undergoing and the result would be suggested in the conference with the further analysis. Conclusion: It will be suggested in the conference.

An Ecological Study on the Risk of Gastric Cancer With Helicobacter Pylori Prevalence and Other Potential Cofactors in Korea

Background: Korea has a high incidence of gastric cancer and a high prevalence of Helicobacter pylori infection. Observation of prevalence trends and determination of risk factors for gastric cancer are important to establish health policies to prevent and reduce the burden of disease. Currently, there is no evidence of complete correlation between prevalence of H. pylori infection and the occurrence of gastric cancer. Several explanations have been proposed for the paradox of high prevalence of infection and low gastric cancer incidence in certain places, including diet and salt consumption, genetic susceptibility, other infections, aflatoxin-contaminated food, and the interaction of all these factors, but none of them has been clearly established. Aim: To explore the potential effects of prevalence of H. pylori infection and other risk factors on gastric cancer incidence in Korea. Methods: Information on gastric cancer incidence, prevalence of H. pylori infection, and the risk factors for gastric cancer were evaluated from nationally representative data - the Korean National Cancer Registry, nationwide routine health check-up surveillance system, and National Health and Nutrition Survey, respectively. Secular trends of H. pylori infection prevalence and age-standardized incidence rates for gastric cancer by region were examined. Furthermore, trends of income level, education level, marital status, number of family members, smoking status, drinking status, obesity, diabetes, hypertension, dyslipidemia, and age-standardized incidence rates for gastric cancer by region were examined. Results: Gastric cancer incidence showed a decreasing trend from 2011 to 2015; 50.6%–44.4% for men and 22.1%–17.0% for women. The prevalence of H. pylori infection also showed a decreasing trend; from 66.9% in 1998%–54.4% in 2011. In Korea, areas with high prevalence of H. pylori infection also showed high gastric cancer incidence. However, the Chungcheong area showed relatively low prevalence of H. pylori infection, but had the highest gastric cancer incidence in Korea. Other factors which showed similar effects on gastric cancer incidence, like H. pylori infection were large family size (4 or more family members), low income, low education, and obesity. The effect of introduction of 'National Cancer Screening Program' will be evaluated in the final outcome. Conclusion: The results of this study indicated that significant regional differences exist between trends in H. pylori infection prevalence and gastric cancer incidence in Korea. Also, the possibility of lack of association between H. pylori prevalence and the incidence of gastric cancer are suggested. Overall, this study suggests the need for further research to explore potential factors accounting for regional differences in gastric cancer incidence in Korea.

Elastostatic reversibility in thermally formed bulk metallic glasses: nanobeam diffraction fluctuation electron microscopy

The unparalleled shaping ability of bulk metallic glasses can revolutionize commercial products having multi-length scale features with a processing time of several minutes. Despite the widespread shaping ability of these polymer-like multicomponent alloys, thermoplastic forming (TPF) can severely degrade the intrinsic properties, particularly when complex stress states are activated. The present work emphasizes the importance of elastostatic loading (ESL) which not only fully reverses deteriorated room temperature plasticity originating under TPF or post-cryostatic conditions, but also activates a rejuvenation mechanism by rendering an extended resistance against strain softening. Furthermore, the reduction in the supercooled liquid region and crystallization enthalpy measured by differential scanning calorimetry are found to be temporary, and can be fully reversed to the initial condition. HRTEM imaging of the samples are performed with an imaging spherical aberration corrector. Individual nanobeam diffraction patterns obtained by the fluctuation electron microscopy (FEM) measurements are acquired using a scanning transmission electron microscope with a probe size of 1.2 nm from a 10 × 10 raster, yielding 100 diffraction patterns. The normalized variance of a series of nanodiffraction patterns of the post-elastostatically loaded sample reveals a height decrease in the first broad peak of normalized intensity variance V(k) suggesting modifications in the medium-range structural order which in turn dramatically restores the mechanical and thermal properties. Overall, the combination of TPF and post-ESL treatment in advanced glassy metals can open a new avenue for ultra-high mechanical and thermal performance micro- and nanomechanical devices for biosensors, MOSFETs and robotics.

The association between season of birth, age at onset, and clozapine use in schizophrenia

OBJECTIVE

This study aimed to determine whether the rate of clozapine use, an indicator of refractoriness in schizophrenia, is associated with the season of birth and age at onset in patients with schizophrenia based on nationwide data.

METHODS

Patients with schizophrenia (n = 114 749) who received prescriptions for antipsychotic medication between 2008 and 2014 were retrospectively identified from the Korean National Health Insurance Service database. The study population was divided into three groups based on their age at the onset of schizophrenia (early, middle, and late onset). We assessed differences in the month of birth between patients and the general population. In addition, the cumulative clozapine use was calculated.

RESULTS

Compared to the late-onset schizophrenia group, the early- and middle-onset groups showed a higher probability of birth during the winter season. In addition, the early-onset group showed the highest cumulative clozapine use rate. In the middle-onset group, the initiation of clozapine use was significantly earlier for patients born in winter compared to those born in summer.

CONCLUSION

Our results indicate that the age at onset is an important factor in predicting the prognosis of schizophrenia patients. The season of birth also affects the prognosis, but with less robustness. Specifically, it appears that early disease onset and winter birth might be associated with poor outcomes in Korean patients with schizophrenia.

Gq-activated fibroblasts induce cardiomyocyte action potential prolongation and automaticity in a three-dimensional microtissue environment

Cardiac fibroblasts (CFs) are known to regulate cardiomyocyte (CM) function in vivo and in two-dimensional in vitro cultures. This study examined the effect of CF activation on the regulation of CM electrical activity in a three-dimensional (3-D) microtissue environment. Using a scaffold-free 3-D platform with interspersed neonatal rat ventricular CMs and CFs, G_q-mediated signaling was selectively enhanced in CFs by Gα_q adenoviral infection before coseeding with CMs in nonadhesive hydrogels. After 3 days, the microtissues were analyzed by signaling assay, histological staining, quantitative PCR, Western blots, optical mapping with voltage- or Ca²⁺-sensitive dyes, and microelectrode recordings of CF resting membrane potential (RMP_CF). Enhanced G_q signaling in CFs increased microtissue size and profibrotic and prohypertrophic markers. Expression of constitutively active Gα_q in CFs prolonged CM action potential duration (by 33%) and rise time (by 31%), prolonged Ca²⁺ transient duration (by 98%) and rise time (by 65%), and caused abnormal electrical activity based on depolarization-induced automaticity. Constitutive G_q activation in CFs also depolarized RMP_CF from -33 to -20 mV and increased connexin 43 and connexin 45 expression. Computational modeling confers that elevated RMP_CF and increased cell-cell coupling between CMs and CFs in a 3-D environment could lead to automaticity. In conclusion, our data demonstrate that CF activation alone is capable of altering action potential and Ca²⁺ transient characteristics of CMs, leading to proarrhythmic electrical activity. Our results also emphasize the importance of a 3-D environment where cell-cell interactions are prevalent, underscoring that CF activation in 3-D tissue plays a significant role in modulating CM electrophysiology and arrhythmias.NEW & NOTEWORTHY In a three-dimensional microtissue model, which lowers baseline activation of cardiac fibroblasts but enables cell-cell, paracrine, and cell-extracellular matrix interactions, we demonstrate that selective cardiac fibroblast activation by enhanced G_q signaling, a pathophysiological trigger in the diseased heart, modulates cardiomyocyte electrical activity, leading to proarrhythmogenic automaticity.