Nur77 induced by HIF-1α mediates vascular remodeling in hypoxic pulmonary hypertension.

Nur77 is a member of the NR4A subfamily of orphan nuclear receptors that is expressed and has a function within the immune system. This study aimed to investigate the role of Nur77 in hypoxic pulmonary hypertension. SPF male SD rats were exposed in hypobaric chamber simulating 5000 m high altitude for 0, 3, 7, 14, 21 or 28 days. Rat pulmonary artery smooth muscle cells (RPASMCs) were cultured under normoxic conditions (5% CO2-95% ambient air) or hypoxic conditions (5% O2 for 6 h, 12 h, 24 h, 48 h). Hypoxic rats developed pulmonary arterial remodeling and right ventricular hypertrophy with significantly increased pulmonary arterial pressure. The levels of Nur77, HIF-1α and PNCA were upregulated in pulmonary arterial smooth muscle from hypoxic rats. Silencing of either Nur77 or HIF-1α attenuated hypoxia-induced proliferation. Silencing of HIF-1α down-regulated Nur77 protein level, but Nur77 silence did not reduce HIF-1α. Nur77 was not con-immunoprecipitated with HIF-1α. This study demonstrated that Nur77 acted as a downstream regulator of HIF-1α under hypoxia, and plays a critical role in the hypoxia-induced pulmonary vascular remodeling, which is regulated by HIF-1α. Nur77 maybe a novel target of HPH therapy.

Quantitative evaluation of the efficacy and safety profiles of two types of targeted inhibitors combined with endocrine therapy in ER+/HER2- metastatic breast cancer.

PURPOSE: The aim of this study was to quantitatively compare the efficacy and safety of CDK4/6 inhibitors and PI3K/AKT/mTOR inhibitors for ER+/HER2- metastatic breast cancer. METHODS: A parametric survival function was used to analyze the time course of overall survival (OS) and progression-free survival (PFS). The objective response rate (ORR) and the incidence of any grade and grade 3-4 adverse events were summarized using the random-effects model of a single-arm meta-analysis. RESULTS: This study included 44 arms from 48 publications, with a total sample size of 7881 patients. Our study revealed that CDK4/6 inhibitors had a median OS of 40.7 months, a median PFS of 14.8 months, and an ORR of 40%, whereas PI3K/AKT/mTOR inhibitors had a median OS of 29.8 months, a median PFS of 8.3 months, and an ORR of 20%. Additionally, this study also found that the proportion of patients with visceral metastases and specific endocrine therapy used in combination significantly impact OS and PFS. In terms of adverse events, CDK4/6 inhibitors exhibited a relatively high incidence of hematological adverse events. CONCLUSION: Our study provides solid quantitative evidence for the first-line recommendation of CDK4/6 inhibitors combined with endocrine therapy for ER+/HER2- metastatic breast cancer in clinical guidelines.

Inhibitory effect of Porphyromonas gingivalis-derived phosphoethanolamine dihydroceramide on acid ceramidase expression in oral squamous cells.

The maintenance of diminished acid ceramidase (ASAH1) gene expression leading to the accumulation of antiproliferative intracellular ceramides in oral squamous cell carcinoma (OSCC) has emerged as a prospective oral cancer therapeutic regimen. Our published study demonstrated that the key periodontal pathogen Porphyromonas gingivalis downregulates the expression patterns of ASAH1 mRNA in normal epithelial cells in vitro. Therefore, P. gingivalis may also beneficially diminish the expression of ASAH1 in OSCC. Because a uniquely structured P. gingivalis-derived phosphoethanolamine dihydroceramide (PEDHC) inhibits the proliferation of normal human fibroblasts, this study aimed to test the effect of PEDHC on the survival of human oral squamous OECM-1 cells in vitro. We demonstrated that the P. gingivalis dihydroceramide-null (ΔPG1780) strain upregulates the expression of ASAH1 mRNA and promotes aggressive proliferation and migration of OECM-1 cells compared to the parent P. gingivalis-W83 strain. In addition, the intracellular concentration of ceramides was dramatically elevated in OECM-1 cells exposed to PEDHC in vitro. Furthermore, PEDHC inhibited expression patterns of ASAH1 mRNA as well as some genes associated with degradation of the basement membranes and extracellular matrix, for example, MMP-2, ADAM-17 and IL-6, in OECM-1 cells. Altogether, these data indicated that PEDHC produced by P. gingivalis inhibits acid ceramidase expression, promotes intracellular ceramide accumulation and suppresses the survival and migration of OSCC cells in vitro. Further studies are needed to determine molecular mechanisms of PEDHC-mediated inhibitory effect(s) on OSCC using in vivo models of oral cancer.

Neutral ceramidase-active site inhibitor chemotypes and binding modes.

Ceramides impact a diverse array of biological functions and have been implicated in disease pathogenesis. The enzyme neutral ceramidase (nCDase) is a zinc-containing hydrolase and mediates the metabolism of ceramide to sphingosine (Sph), both in cells and in the intestinal lumen. nCDase inhibitors based on substrate mimetics, for example C6-urea ceramide, have limited potency, aqueous solubility, and micelle-free fraction. To identify non-ceramide mimetic nCDase inhibitors, hit compounds from an HTS campaign were evaluated in biochemical, cell based and in silico modeling approaches. A majority of small molecule nCDase inhibitors contained pharmacophores capable of zinc interaction but retained specificity for nCDase over zinc-containing acid and alkaline ceramidases, as well as matrix metalloprotease-3 and histone deacetylase-1. nCDase inhibitors were refined by SAR, were shown to be substrate competitive and were active in cellular assays. nCDase inhibitor compounds were modeled by in silico DOCK screening and by molecular simulation. Modeling data supports zinc interaction and a similar compound binding pose with ceramide. nCDase inhibitors were identified with notably improved activity and solubility in comparison with the reference lipid-mimetic C6-urea ceramide.

[Impact of Endometriosis on the Therapeutic Effect of Hysteroscopic Fallopian Tube Catheterization Combined With Laparoscopy in Infertile Patients With Proximal Tubal Obstruction].

Objective: To investigate the impact of endometriosis on the therapeutic effect of hysteroscopic fallopian tube catheterization combined with laparoscopy in infertile patients with proximal tubal obstruction. Methods: We conducted a retrospective analysis of patients who underwent hysteroscopic fallopian tube catheterization combined with laparoscopy for infertility caused by proximal fallopian tube obstruction between January 19, 2016 and March 20, 2020 at the Department of Reproductive Endocrinology, West China Second Hospital, Sichuan University. During the operation, hydrotubation was performed to verify whether there was proximal tubal obstruction. Then, the patients were categorized into an endometriosis group and a non-endometriosis group according to whether their proximal tubal obstruction was combined with endometriosis. The baseline data were balanced by propensity score matching and the rate of successful surgical unblocking of proximal tubal obstruction in infertile patients by hysteroscopic fallopian tube catheterization combined with laparoscopy was calculated. Treating cases lost to follow-up in both groups as non-pregnant cases according to the principle of intention-to-treat analysis, we followed up the pregnancy outcomes after surgery. The primary indicators included overall successful surgical unblocking rate, clinical pregnancy rate, and spontaneous pregnancy rate, while the secondary indicators included live birth rate, miscarriage rate, ectopic pregnancy rate, and the mean time to spontaneous pregnancy after surgery. The primary indicators included overall successful surgical unblocking rate, clinical pregnancy rate, and spontaneous conception rate, while the secondary indicators included live birth rate, miscarriage rate, ectopic pregnancy rate, and the mean time to spontaneous pregnancy after surgery. Results: After propensity score matching, 113 cases were included in each of the two groups, with the overall successful surgical unblocking rate being 72.6%. The successful surgical unblocking rate of patients in the endometriosis group was higher than that of the non-endometriosis group, with the difference being statistically significant (78.8% vs. 66.4%, P<0.05). A total of 38 patients were lost after follow-up matching. Postoperative follow-up was performed to date and, through intention-to-treat analysis, the spontaneous conception rate was found to be higher in the endometriosis group than that in the non-endometriosis group (44.2% vs. 30.1%, P<0.05), while the mean time to spontaneous pregnancy after surgery was shorter in the endometriosis group than that in the non-endometriosis group (46 months vs. 53 months, P<0.05). There was no significant difference in clinical pregnancy rate, live birth rate, miscarriage rate, and ectopic pregnancy rate between the endometriosis group and the non-endometriosis group ( P>0.05). Conclusion: When infertility caused by proximal tubal obstruction is combined with endometriosis, performing hysteroscopic fallopian tube catheterization combined with laparoscopy contributes to the improvement of reproduction outcomes.

Manifold Roles of Ceramide Metabolism in Non-Alcoholic Fatty Liver Disease and Liver Cancer.

Non-alcoholic fatty liver disease (NAFLD) is a metabolic disorder manifested in hepatic fat accumulation (hepatic steatosis) in the absence of heavy alcohol use. NAFLD consists of four major stages ranging from simple steatosis or non-alcoholic fatty liver (NAFL) to more advanced stages, non-alcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. NFLAD may further advance to hepatocellular carcinoma (HCC). Primary causes of NAFLD are obesity and obesity-associated insulin resistance (IR). As a result of the obesity pandemic, NAFLD has become one of the most common liver disorders worldwide and both the incidence and mortality rate of HCC that develops from NAFLD are increasing steadily. As treatment options are not available for advanced NAFLD, a better understanding of the molecular mechanisms for NAFLD development and progression is urgently needed. Emerging evidence suggests that dysregulation of the metabolism of sphingolipids contributes to development and progression of NAFLD and NAFLD-associated HCC. The present chapter summarizes roles of bioactive sphingolipids, ceramides, sphingosine, and sphingosine-1-phosphate (S1P) and their metabolizing enzymes in NAFLD and HCC.

[Clinical and genetic analysis of two patients with CHARGE syndrome due to de novo variants of CHD7 gene].

OBJECTIVE: To analyze the clinical characteristics and genetic basis of two children patients with CHARGE syndrome. METHODS: The clinical features of the two patients were analyzed, and potential variants were detected by Trio whole exome sequencing (trio-WES) of the probands and their parents. RESULTS: Child 1 has manifested cerebellar vermis dysplasia, enlargement of cerebral ventricles, whereas child 2 manifested with infantile spasm and congenital hip dysplasia. Both children were found to harbor de novo heterozygous variants of the CHD7 gene, namely c.4015C>T (exon 17) and c.5050G>A (exon 22). Based on the guidelines of the American College of Medical Genetics and Genomics, the two variants were rated as pathogenic variants, and the related disease was CHARGE syndrome. Furthermore, child 2 was also found to harbor a novel heterozygous c.6161A>C (p.Gln2054Pro) missense variant of COL12A1 gene, which was rated as possibly pathogenic, and the associated disease was Bethlem myopathy type 2, which is partially matched with the patient' s clinical phenotype. CONCLUSION: The special clinical phenotypes shown by the two children harboring novel CHD7 variants have further expanded the phenotypic spectrum of CHARGE syndrome.

Maternal and fetal alkaline ceramidase 2 is required for placental vascular integrity in mice.

Sphingolipids have been implicated in mammalian placental development and function, but their regulation in the placenta remains unclear. Herein we report that alkaline ceramidase 2 (ACER2) plays a key role in sustaining the integrity of the placental vasculature by regulating the homeostasis of sphingolipids in mice. The mouse alkaline ceramidase 2 gene (Acer2) is highly expressed in the placenta between embryonic day (E) 9.5 and E12.5. Acer2 deficiency in both the mother and fetus decreases the placental levels of sphingolipids, including sphingoid bases (sphingosine and dihydrosphingosine) and sphingoid base-1-phosphates (sphingosine-1-phosphate and dihydrosphingosine-1-phosphate) and results in the in utero death of ≈50% of embryos at E12.5 whereas Acer2 deficiency in either the mother or fetus has no such effects. Acer2 deficiency causes hemorrhages from the maternal vasculature in the junctional and/or labyrinthine zones in E12.5 placentas. Moreover, hemorrhagic but not non-hemorrhagic Acer2-deficient placentas exhibit an expansion of parietal trophoblast giant cells with a concomitant decrease in the area of the fetal blood vessel network in the labyrinthine zone, suggesting that Acer2 deficiency results in embryonic lethality due to the atrophy of the fetal blood vessel network in the placenta. Taken together, these results suggest that ACER2 sustains the integrity of the placental vasculature by controlling the homeostasis of sphingolipids in mice.

Developing a physiologically based pharmacokinetic model of apixaban to predict scenarios of drug-drug interactions, renal impairment and paediatric populations.

AIMS: To develop a physiologically based pharmacokinetic (PBPK) model for apixaban, an oral anticoagulant with a narrow therapeutic index, and to predict PK profiles and potential drug-drug interactions (DDIs) in patients with renal impairment and paediatrics. METHODS: A whole-body apixaban PBPK model was developed and validated in SimCYP for healthy adults with or without interacting drugs. The model was extended to renal impairment and paediatrics. Observed PK data in adults were compared with predicted data. The effect of renal function, age and DDIs on apixaban PK was investigated. RESULTS: The PBPK model successfully predicted the PK of apixaban alone and under the influence of interacting drugs. For patients with renal impairment, the PBPK model successfully predicted the fold change in each impairment group; inhibitory DDI and renal impairment had a synergistic effect on the increase of apixaban exposure (e.g., almost 3-fold increase of AUC in ketoconazole + severe renal impairment group). For infants younger than 1 year, the exposure of apixaban decreased with increased weight-normalized clearance. For newborn infants, AUC of apixaban was >2-fold higher than that in children older than 1 year. Meanwhile, the effect of DDI seems to be weakened while the effect of renal impairment might be enhanced in infants younger than 1 year. CONCLUSION: Our study provides a reasonable approach to estimate the dose adjustment for the first use of apixaban in special populations with complex situations, which has the opportunity to make the clinical practice much safer.

Correction: Alkaline Ceramidase 3 Deficiency Results in Purkinje Cell Degeneration and Cerebellar Ataxia Due to Dyshomeostasis of Sphingolipids in the Brain.

[This corrects the article DOI: 10.1371/journal.pgen.1005591.].

Freestanding Oxide Ferroelectric Tunnel Junction Memories Transferred onto Silicon.

Crystalline oxide ferroelectric tunnel junctions enable persistent encoding of information in electric polarization, featuring nondestructive readout and scalability that can exceed current commercial high-speed, nonvolatile ferroelectric memories. However, the well-established fabrication of epitaxial devices on oxide substrates is difficult to adapt to silicon substrates for integration into complementary metal-oxide-semiconductor electronics. In this work, we report ferroelectric tunnel junctions based on 2.8 nm-thick BaTiO3 films grown epitaxially on SrTiO3 growth substrates, released, and relaminated onto silicon. The performance of the transferred devices is comparable to devices characterized on the oxide substrate, suggesting a viable route toward next-generation nonvolatile memories broadly integrable with different materials platforms.

New fluorogenic probes for neutral and alkaline ceramidases.

New fluorogenic ceramidase substrates derived from the N-acyl modification of our previously reported probes (RBM14) are reported. While none of the new probes were superior to the known RBM14C12 as acid ceramidase substrates, the corresponding nervonic acid amide (RBM14C24:1) is an efficient and selective substrate for the recombinant human neutral ceramidase, both in cell lysates and in intact cells. A second generation of substrates, incorporating the natural 2-(N-acylamino)-1,3-diol-4-ene framework (compounds RBM15) is also reported. Among them, the corresponding fatty acyl amides with an unsaturated N-acyl chain can be used as substrates to determine alkaline ceramidase (ACER)1 and ACER2 activities. In particular, compound RBM15C18:1 has emerged as the best fluorogenic probe reported so far to measure ACER1 and ACER2 activities in a 96-well plate format.

Alkaline ceramidase 2 is essential for the homeostasis of plasma sphingoid bases and their phosphates.

Sphingosine-1-phosphate (S1P) plays important roles in cardiovascular development and immunity. S1P is abundant in plasma because erythrocytes-the major source of S1P-lack any S1P-degrading activity; however, much remains unclear about the source of the plasma S1P precursor, sphingosine (SPH), derived mainly from the hydrolysis of ceramides by the action of ceramidases that are encoded by 5 distinct genes, acid ceramidase 1 ( ASAH1)/ Asah1, ASAH2/ Asah2, alkaline ceramidase 1 ( ACER1)/ Acer1, ACER2/ Acer2, and ACER3/ Acer3, in humans/mice. Previous studies have reported that knocking out Asah1 or Asah2 failed to reduce plasma SPH and S1P levels in mice. In this study, we show that knocking out Acer1 or Acer3 also failed to reduce the blood levels of SPH or S1P in mice. In contrast, knocking out Acer2 from either whole-body or the hematopoietic lineage markedly decreased the blood levels of SPH and S1P in mice. Of interest, knocking out Acer2 from whole-body or the hematopoietic lineage also markedly decreased the levels of dihydrosphingosine (dhSPH) and dihydrosphingosine-1-phosphate (dhS1P) in blood. Taken together, these results suggest that ACER2 plays a key role in the maintenance of high plasma levels of sphingoid base-1-phosphates-S1P and dhS1P-by controlling the generation of sphingoid bases-SPH and dhSPH-in hematopoietic cells.-Li, F., Xu, R., Low, B. E., Lin, C.-L., Garcia-Barros, M., Schrandt, J., Mileva, I., Snider, A., Luo, C. K., Jiang, X.-C., Li, M.-S., Hannun, Y. A., Obeid, L. M., Wiles, M. V., Mao, C. Alkaline ceramidase 2 is essential for the homeostasis of plasma sphingoid bases and their phosphates.

Application of physiologically based pharmacokinetic modeling to the prediction of drug-drug and drug-disease interactions for rivaroxaban.

PURPOSE: Rivaroxaban is a direct oral anticoagulant with a large inter-individual variability. The present study is to develop a physiologically based pharmacokinetic (PBPK) model to predict several scenarios in clinical practice. METHODS: A whole-body PBPK model for rivaroxaban, which is metabolized by the cytochrome P450 (CYP) 3A4/5, 2J2 pathways and excreted via kidneys, was developed to predict the pharmacokinetics at different doses in healthy subjects and patients with hepatic or renal dysfunction. Hepatic clearance and drug-drug interactions (DDI) were estimated by in vitro in vivo extrapolation (IVIVE) based on parameters obtained from in vitro experiments. To validate the model, observed concentrations were compared with predicted concentrations, and the impact of special scenarios was investigated. RESULTS: The PBPK model successfully predicted the pharmacokinetics for healthy subjects and patients as well as DDIs. Sensitivity analysis shows that age, renal, and hepatic clearance are important factors affecting rivaroxaban pharmacokinetics. The predicted fold increase of rivaroxaban AUC values when combined administered with the inhibitors such as ketoconazole, ritonavir, and clarithromycin were 2.3, 2.2, and 1.3, respectively. When DDIs and hepatic dysfunction coexist, the fold increase of rivaroxaban exposure would increase significantly compared with one factor alone. CONCLUSIONS: Our study using PBPK modeling provided a reasonable approach to evaluate exposure levels in special patients under special scenarios. Although further clinical study or real-life experience would certainly merit the current work, the modeling work so far would at least suggest caution of using rivaroxaban in complicated clinical settings.

Alkaline Ceramidase 3 Deficiency Results in Purkinje Cell Degeneration and Cerebellar Ataxia Due to Dyshomeostasis of Sphingolipids in the Brain.

Dyshomeostasis of both ceramides and sphingosine-1-phosphate (S1P) in the brain has been implicated in aging-associated neurodegenerative disorders in humans. However, mechanisms that maintain the homeostasis of these bioactive sphingolipids in the brain remain unclear. Mouse alkaline ceramidase 3 (Acer3), which preferentially catalyzes the hydrolysis of C18:1-ceramide, a major unsaturated long-chain ceramide species in the brain, is upregulated with age in the mouse brain. Acer3 knockout causes an age-dependent accumulation of various ceramides and C18:1-monohexosylceramide and abolishes the age-related increase in the levels of sphingosine and S1P in the brain; thereby resulting in Purkinje cell degeneration in the cerebellum and deficits in motor coordination and balance. Our results indicate that Acer3 plays critically protective roles in controlling the homeostasis of various sphingolipids, including ceramides, sphingosine, S1P, and certain complex sphingolipids in the brain and protects Purkinje cells from premature degeneration.

Deficiency of the sphingosine-1-phosphate lyase SGPL1 is associated with congenital nephrotic syndrome and congenital adrenal calcifications.

We identified two unrelated consanguineous families with three children affected by the rare association of congenital nephrotic syndrome (CNS) diagnosed in the first days of life, of hypogonadism, and of prenatally detected adrenal calcifications, associated with congenital adrenal insufficiency in one case. Using exome sequencing and targeted Sanger sequencing, two homozygous truncating mutations, c.1513C>T (p.Arg505*) and c.934delC (p.Leu312Phefs*30), were identified in SGPL1-encoding sphingosine-1-phosphate (S1P) lyase 1. SGPL1 catalyzes the irreversible degradation of endogenous and dietary S1P, the final step of sphingolipid catabolism, and of other phosphorylated long-chain bases. S1P is an intracellular and extracellular signaling molecule involved in angiogenesis, vascular maturation, and immunity. The levels of SGPL1 substrates, S1P, and sphingosine were markedly increased in the patients' blood and fibroblasts, as determined by liquid chromatography-tandem mass spectrometry. Vascular alterations were present in a patient's renal biopsy, in line with changes seen in Sgpl1 knockout mice that are compatible with a developmental defect in vascular maturation. In conclusion, loss of SGPL1 function is associated with CNS, adrenal calcifications, and hypogonadism.

Quantitative efficacy of topical administration of tranexamic acid on postoperative bleeding in total knee arthroplasty.

AIMS: Topical tranexamic acid (TXA) is used in patients undergoing total knee arthroplasty to reduce perioperative blood loss. However, the optimal dosing regimen remains undetermined. The aim of the present study was to quantitatively evaluate the effect of topical TXA on the reduction of postoperative drainage, and identify the dosing regimen factors affecting the efficacy of topical TXA. METHODS: Model-based meta-analysis was used to evaluate the efficacy of topical TXA and the dosing regimen factors influencing clinical efficacy. Data from a systemic literature search was identified and used to build a time-effect model for placebo and TXA in treating perioperative blood loss. RESULTS: Fourteen studies containing 16 TXA-control groups of drainage volume data were included for MBMA modelling. The model described the postoperative drainage-time profiles adequately. According to the model estimation, TXA can finally reduce the postoperative drainage by about 41.7%, and 10.9 h was needed to reach 50% of the maximal drainage volume. Covariate analysis indicated that both dose and contact time alone did not correlate well with clinical efficacy. However, when considered together, they can dramatically improve fitting of the data. Simulation showed that increasing dose or contact time extensively would produce a plateau-like effect: 2-3 g TXA with contact time of 1-2 h would yield >60% reduction in the drainage volume. CONCLUSIONS: Dose and contact time together determined the efficacy of TXA. Extensively large dose or long contact time seems unnecessary. These findings may further guide the clinical practice on the topical TXA regimen optimization.

Deficiency of the alkaline ceramidase ACER3 manifests in early childhood by progressive leukodystrophy.

BACKGROUND/AIMS: Leukodystrophies due to abnormal production of myelin cause extensive morbidity in early life; their genetic background is still largely unknown. We aimed at reaching a molecular diagnosis in Ashkenazi-Jewish patients who suffered from developmental regression at 6-13 months, leukodystrophy and peripheral neuropathy. METHODS: Exome analysis, determination of alkaline ceramidase activity catalysing the conversion of C18:1-ceramide to sphingosine and D-ribo-C12-N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) (NBD)-phytoceramide to NBD-C12-fatty acid using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and thin layer chromatography, respectively, and sphingolipid analysis in patients' blood by LC-MS/MS. RESULTS: The patients were homozygous for p.E33G in the ACER3, which encodes a C18:1-alkaline ceramidase and C20:1-alkaline ceramidase. The mutation abolished ACER3 catalytic activity in the patients' cells and failed to restore alkaline ceramidase activity in yeast mutant strain. The levels of ACER3 substrates, C18:1-ceramides and dihydroceramides and C20:1-ceramides and dihydroceramides and other long-chain ceramides and dihydroceramides were markedly increased in the patients' plasma, along with that of complex sphingolipids, including monohexosylceramides and lactosylceramides. CONCLUSIONS: Homozygosity for the p.E33G mutation in the ACER3 gene results in inactivation of ACER3, leading to the accumulation of various sphingolipids in blood and probably in brain, likely accounting for this new form of childhood leukodystrophy.

Nanodomain Engineering in Ferroelectric Capacitors with Graphene Electrodes.

Polarization switching in ferroelectric capacitors is typically realized by application of an electrical bias to the capacitor electrodes and occurs via a complex process of domain structure reorganization. As the domain evolution in real devices is governed by the distribution of the nucleation centers, obtaining a domain structure of a desired configuration by electrical pulsing is challenging, if not impossible. Recent discovery of polarization reversal via the flexoelectric effect has opened a possibility for deterministic control of polarization in ferroelectric capacitors. In this paper, we demonstrate mechanical writing of arbitrary-shaped nanoscale domains in thin-film ferroelectric capacitors with graphene electrodes facilitated by a strain gradient induced by a tip of an atomic force microscope (AFM). A phase-field modeling prediction of a strong effect of graphene thickness on the threshold load required to initiate mechanical switching has been confirmed experimentally. Deliberate voltage-free domain writing represents a viable approach for development of functional devices based on domain topology and electronic properties of the domains and domain walls.