Face Transplantation: Partial Graft Loss of the First Case 10 Years Later.

Ten years after the first face transplantation, we report the partial loss of this graft. After two episodes of acute rejection (AR) occurred and completely reversed in the first posttransplantation year, at 90 months posttransplantation the patient developed de novo class II donor-specific antibodies, without clinical signs of AR. Some months later, she developed several skin rejection episodes treated with steroid pulses. Despite rapid clinical improvement, some months later the sentinel skin graft underwent necrosis. Microscopic examination showed intimal thickening, thrombosis of the pedicle vessel, and C4d deposits on the endothelium of some dermal vessels of the facial graft. Flow magnetic resonance imaging of the facial graft showed a decrease of the distal right facial artery flow. Three steroid pulses of 500 mg each, followed by intravenous immunoglobulins (2 g/kg), five sessions of plasmapheresis, and three cycles of bortezomib 1.3 mg/m2 , were administered. Despite rescue therapy with eculizumab, necrosis of the lips and the perioral area occurred, which led to surgical removal of the lower lip, labial commissures, and part of the right cheek in May 2015. In January 2016, the patient underwent conventional facial reconstruction because during the retransplantation evaluation a small-cell lung carcinoma was discovered, causing the patient's death in April 2016.

Predictive Modeling of Tacrolimus Dose Requirement Based on High-Throughput Genetic Screening.

Any biochemical reaction underlying drug metabolism depends on individual gene-drug interactions and on groups of genes interacting together. Based on a high-throughput genetic approach, we sought to identify a set of covariant single-nucleotide polymorphisms predictive of interindividual tacrolimus (Tac) dose requirement variability. Tac blood concentrations (Tac C0 ) of 229 kidney transplant recipients were repeatedly monitored after transplantation over 3 mo. Given the high dimension of the genomic data in comparison to the low number of observations and the high multicolinearity among the variables (gene variants), we developed an original predictive approach that integrates an ensemble variable-selection strategy to reinforce the stability of the variable-selection process and multivariate modeling. Our predictive models explained up to 70% of total variability in Tac C0 per dose with a maximum of 44 gene variants (p-value <0.001 with a permutation test). These models included molecular networks of drug metabolism with oxidoreductase activities and the multidrug-resistant ABCC8 transporter, which was found in the most stringent model. Finally, we identified an intronic variant of the gene encoding SLC28A3, a drug transporter, as a key gene involved in Tac metabolism, and we confirmed it in an independent validation cohort.

[Long-term blood pressure outcome after unilateral adrenalectomy for primary hyperaldosteronism]. / Contrôle à long terme de la pression artérielle après surrénalectomie pour hyperaldostéronisme primaire.

OBJECTIVES: To evaluate long-term results of adrenalectomy for primary aldosteronism (PA) and to identify prognostic factors associated. METHODS: Exhaustive retrospective review of all consecutive patients undergoing adrenalectomy for PA between 2002 and 2013 in our department. All patients underwent preoperative: clinical evaluation (age, sex, height, weight, systolic and diastolic BP under treatment, identification of anti-hypertension treatment), biological evaluation (potassium, renin, aldosterone) and radiological evaluation (CT and/or MRI). Blood pressure was assessed postoperatively at 1 month, 1 year, then at the date of the latest news. The patients were classified into three categories: cured (no antihypertensive therapy in postoperative associated with strictly lower blood pressures of 140/90mmHg), improved (decreased number of drugs or number unchanged but with better blood pressure control), and refractory (no change in the number of drug and blood pressure, or deterioration of one or other of these two parameters). RESULTS: We evaluated 43 patients, 23 men and 20 women, with a median follow-up of 74.4 months [16.8 to 141]. Pathological analysis described 34 adenomas (79%), 7 hyperplasias (16%) (5 micro-nodular and 2 macro-nodular) and 2 adrenocortical carcinoma (5%). The postoperative long-term assessment found 20% of cured patients (n=8), 65% of improved (n=26) and 15% of refractory (n=6). Prognostic factors associated with favorable long-term blood pressure outcome were those typically associated with ARS score [preoperative number of anti-hypertension drugs (P=0.005), BMI<25kg/m2 (P=0.009), and duration of hypertension (P=0.007)]. CONCLUSION: Adrenalectomy for PA is a long-term effective treatment for blood pressure control. Prognostic factors associated with long-term success are those conventionally described in ARS score. LEVEL OF EVIDENCE: 4.

Long-Term Clinical Impact of Adaptation of Initial Tacrolimus Dosing to CYP3A5 Genotype.

Pretransplantation adaptation of the daily dose of tacrolimus to CYP3A5 genotype is associated with improved achievement of target trough concentration (C0 ), but whether this improvement affects clinical outcomes is unknown. In the present study, we have evaluated the long-term clinical impact of the adaptation of initial tacrolimus dosing according to CYP3A5 genotype: The transplantation outcomes of the 236 kidney transplant recipients included in the Tactique study were retrospectively investigated over a period of more than 5 years. In the Tactique study, patients were randomly assigned to receive tacrolimus at either a fixed dosage or a dosage determined by their genotype, and the primary efficacy end point was the proportion of patients for whom tacrolimus C0 was within target range (10-15 ng/mL) at day 10. Our results indicate that the incidence of biopsy-proven acute rejection and graft survival were similar between the control and the adapted tacrolimus dose groups, as well as between the patients who achieve the tacrolimus C0 target ranges earlier. Patients' death, cancer, cardiovascular events, and infections were also similar, and renal function did not change. We conclude that optimization of initial tacrolimus dose using pharmacogenetic testing does not improve clinical outcomes.

Kidney transplant recipients carrying the CYP3A4*22 allelic variant have reduced tacrolimus clearance and often reach supratherapeutic tacrolimus concentrations.

CYP3A4*22 is an allelic variant of the cytochrome P450 3A4 associated with a decreased activity. Carriers of this polymorphism may require reduced tacrolimus (Tac) doses to reach the target residual concentrations (Co). We tested this hypothesis in a population of kidney transplant recipients extracted from a multicenter, prospective and randomized study. Among the 186 kidney transplant recipients included, 9.3% (18 patients) were heterozygous for the CYP3A4*22 genotype and none were homozygous (allele frequency of 4.8%). Ten days after transplantation (3 days after starting treatment with Tac), 11% of the CYP3A4*22 carriers were within the target range of Tac Co (10-15 ng/mL), whereas among the CYP3A4*1/*1 carriers, 40% were within the target range (p = 0.02, OR = 0.19 [0.03; 0.69]). The mean Tac Co at day 10 in the CYP3A4*1/*22 group was 23.5 ng/mL (16.6-30.9) compared with 15.1 ng/mL (14-16.3) in the CYP3A4*1/*1 group, p < 0.001. The Tac Co/dose significantly depended on the CYP3A4 genotype during the follow-up (random effects model, p < 0.001) with the corresponding equivalent dose for patients heterozygous for CYP3A4*22 being 0.67 [0.54; 0.84] times the dose for CYP3A4*1/*1 carriers. In conclusion, the CYP3A4*22 allelic variant is associated with a significantly altered Tac metabolism and carriers of this polymorphism often reach supratherapeutic concentrations.

The nephroprotective properties of recombinant human erythropoietin in kidney transplantation: experimental facts and clinical proofs.

Adaptive responses to hypoxia, including hypoxia-inducible factor signaling, allow the cell to satisfy its basal metabolic demand and avoid death, but these responses can also be deleterious by promoting inflammation, cell dedifferentiation and fibrogenesis. Therefore, targeting hypoxia constitutes a promising therapeutic avenue. Recombinant human erythropoietin (rhEPO) appeared as a good candidate therapy because its hematopoietic properties could reverse anemia, and its tissue-protective properties could reduce cell death and limit maladaptive cellular responses to hypoxia. Despite experimental evidence on the nephroprotecive properties of rhEPO, recent clinical trials provided evidence that rhEPO was ineffective in preventing delayed graft function after ischemic acute injury but that the normalization of hemoglobin values preserved kidney function deterioration and reduced graft loss. Our aim here is to provide a survey of the rationale for evaluating the administration of rhEPO in the setting of kidney transplantation. We will discuss the intriguing findings that emerged from the clinical trials and the discrepancies between promising experimental results and negative clinical studies, as well as the differences in terms of the benefits and safety profiles of the normalization of hemoglobin values in chronic kidney disease patients and kidney transplant patients.

The onset of left ventricular diastolic dysfunction in SHR rats is not related to hypertrophy or hypertension.

Left ventricular (LV) diastolic dysfunction, particularly relaxation abnormalities, are known to be associated with the development of LV hypertrophy (LVH). Preliminary human and animal studies suggested that early LV diastolic dysfunction may be revealed independently of LVH. However, whether LV diastolic dysfunction is compromised before the onset of hypertension and LVH remains unknown. We therefore evaluated LV diastolic function in spontaneously hypertensive rats (SHR) at different ages and tested whether LV diastolic dysfunction is associated with abnormal intracellular calcium homeostasis. LV systolic and diastolic functions were evaluated by invasive and echocardiographic methods in 3-week-old (without hypertension) and 5-week-old (with hypertension) SHR and Wistar-Kyoto control rats. Basal intracytoplasmic calcium and sarcoplasmic reticulum (SR) Ca(2+) contents were measured in cardiomyocytes using fura-2 AM. Sarco(endo)plasmic Ca(2+)-ATPase isoform 2a (SERCA 2a) and phospholamban (PLB) expressions were quantified by Western blot and quantitative RT-PCR techniques. LV relaxation dysfunction was observed in 3-week-old SHR rats before onset of hypertension and LVH. An increase in basal intracytoplasmic Ca(2+) and a decrease in SR Ca(2+) release were demonstrated in SHR. Decreased expression of SERCA 2a and Ser16 PLB (p16-PLB) protein levels was also observed in SHR rats, whereas mRNA expression was not decreased. For the first time, we have shown that LV myocardial dysfunction precedes hypertension in 3-week-old SHR rats. This LV myocardial dysfunction was associated with high diastolic [Ca(2+)](i) possibly due to decreased SERCA 2a and p16-PLB protein levels. Diastolic dysfunction may be a potential predictive marker of arterial hypertension in genetic hypertension syndromes.

FGF23 is independently associated with vascular calcification but not bone mineral density in patients at various CKD stages.

SUMMARY: The hormone fibroblast growth factor 23 (FGF23) is involved in mineral homeostasis but may also have a role in vascular calcification and bone mineralization. In a cohort of 142 patients with CKD stages 2-5D, plasma FGF23 was independently associated with aortic calcification but not with pulse wave velocity or bone mineral density. INTRODUCTION: FGF23 is involved in mineral homeostasis but may also have a role in vascular calcification and bone mineralization. Previous studies related to FGF23 and vascular and bone outcomes have been restricted to dialysis patients. The aim of the present study was to establish whether or not plasma FGF23 is associated with aortic and coronary calcification, arterial stiffness, and bone mineral density in patients with early as well as late stages of CKD. METHODS: In a cohort of 142 patients with CKD stages 2-5D, we made routine biochemistry and intact FGF23 determinations, and assessed aortic and coronary calcification, bone mineral density (BMD), and arterial stiffness by multislice spiral computed tomography and automated pulse wave velocity (PWV). RESULTS: Plasma intact FGF23 levels were elevated in CKD patients; the elevation preceded that of serum phosphate in early-stage CKD. Patients with elevated FGF23 levels had higher aortic and coronary calcification scores than patients with lower FGF23 levels. Multivariate linear regression analysis indicated that only age (p < 0.001) and FGF23 (p = 0.008) were independently associated with aortic calcification score. Plasma FGF23 was neither associated with PWV nor with BMD. CONCLUSION: Our data suggest that plasma FGF23 is an independent biomarker of vascular calcification in patients with various CKD stages including early stages. The association between vascular calcification and FGF23 levels appears to be independent of BMD. It remains to be seen whether this association is independent of bone turnover and bone mass.

Renal transplantation in patients with AA amyloidosis nephropathy: results from a French multicenter study.

Although end-stage renal disease related to AA amyloidosis nephropathy is well characterized, there are limited data concerning patient and graft outcome after renal transplantation. We performed a multicentric retrospective survey to assess the graft and patient survival in 59 renal recipients with AA amyloidosis. The recurrence rate of AA amyloidosis nephropathy was estimated at 14%. The overall, 5- and 10-year patient survival was significantly lower for the AA amyloidosis patients than for a control group of 177 renal transplant recipients (p = 0.0001, 0.028 and 0.013, respectively). In contrast, we did not observe any statistical differences in the 5- and 10- year graft survival censored for death between two groups. AA amyloidosis-transplanted patients exhibited a high proportion of infectious complications after transplantation (73.2%). Causes of death included both acute cardiovascular events and fatal septic complications. Multivariate analysis demonstrated that the recurrence of AA amyloidosis on the graft (adjusted OR = 14.4, p = 0.01) and older recipient age (adjusted OR for a 1-year increase = 1.06, p = 0.03) were significantly associated with risk of death. Finally, patients with AA amyloidosis nephropathy are eligible for renal transplantation but require careful management of both cardiovascular and infectious complications to reduce the high risk of mortality.

Serum procalcitonin does not differentiate between infection and disease flare in patients with systemic lupus erythematosus.

Systemic erythematosus lupus (SLE) is a common autoimmune disease. Disease flares may mimic infection with fever, inflammatory syndrome and chills, sometimes resulting in a difficult differential diagnosis. Elevated serum procalcitonin (PCT) levels have been reported to be predictive of bacterial infections, but with conflicting results. The value of serum procalcitonin has not been assessed in large series of SLE. We aimed to describe the distribution of PCT levels in SLE patients with and without flares, to assess the factors associated with increased PCT levels, and to determine the positive and negative predictive values of increased PCT for bacterial infection in SLE patients. Hospitalized SLE patients were included in a retrospective study. Serum PCT had been assayed, or a serum sample had been frozen on admission, before treatment modification. Serum PCT, measured by an automated immunofluorometric assay, and SLEDAI were assessed at the same time. Some 53 women (median age: 33.7 years, range 16-76) and seven men (median age: 52.5 years ± 19) were included. The median SLEDAI for patients with flare (n = 16, 28%) was 2 (range: 0-29). Five patients (8%) had systemic infection. Only one patient had increased PCT levels. Men had significantly higher PCT levels than women (0.196 ± 0.23 versus 0.066 ± 0.03, p < 0.01) and a significant correlation was observed between PCT, age, erythrocyte sedimentation rate, and C-reactive protein. We conclude that PCT levels were within the normal range in infected and non-infected SLE patients and there was no ability to differentiate SLE patients with or without bacterial infection.

High dose epoetin beta in the first weeks following renal transplantation and delayed graft function: Results of the Neo-PDGF Study.

Erythropoietin promotes nephroprotection in animal models of ischemia-reperfusion injury. Neorecormon and Prevention of Delayed Graft Function (Neo-PDGF) is a French open-label multicenter randomized study to evaluate the effect of high doses of epoetin beta (EPO-beta) during the first 2 weeks of renal transplantation on renal function in patients at risk for delayed graft function (DGF). One hundred and four patients were included in the study. Patients randomized in treatment group (A) received four injections of EPO-beta (30.000 UI each), given before surgery and at 12 h, 7 days and 14 days posttransplantation. Patients randomized in control group (B) did not receive EPO-beta. Immunosuppression included induction with basiliximab and maintenance therapy with steroids, mycophenolate mofetil and tacrolimus. At 1 month posttransplant, the estimated glomerular filtration rate (MDRD formula) was 42.5 +/- 19.0 mL/min in the EPO-beta group and 44.0 +/- 16.3 mL/min in the control group (p = ns). The frequency of DGF was similar in both groups (32% vs. 38.8%; p = ns). No difference in the incidence of serious adverse events was observed. (ClinicalTrials.gov number, NCT00815867.).

[Adrenal hemorrhage acutised by adrenocorticotropin hormone]. / Hématomes surrénaliens potentialisés par le Synacthène (HSS).

OBJECTIVE: Many spontaneous adrenal hematomas have been observed in patients being treated by Synacthène. The purpose of this study is to define how to take those patients in charge on a short-, mid- and long-term. PATIENTS AND METHODS: From January 2000 to December 2008, five patients (four males and one female), mean age 47, were taken in charge in our service for spontaneous adrenal hematomas. All those patients had been treated with Synacthène for a mid-sciatic pain for 72 hours. We associated a clinical, endocrine and radiologic staging to treat those patients. RESULTS: Four patients underwent a watchful waiting, only one patient needed surgery. No adrenal tumor was ever found during the mean two years follow-up (one to four). Two patients suffered of the condition of the antiphospholipid syndrome. CONCLUSION: Spontaneous adrenal hematomas are a most uncommon pathology. The clinical attitude has thus to be defined clearly. The patient must be under close clinical evaluation. Biological and morphological parameters have to be often repeated. An adrenal tumor has to be excluded by the evaluation, as that tumor could be secreting or could not be secreting. Antiphospholipid syndrome must also be excluded.

Glycogen synthase kinase-3beta is a negative regulator of cardiomyocyte hypertrophy.

Hypertrophy is a basic cellular response to a variety of stressors and growth factors, and has been best characterized in myocytes. Pathologic hypertrophy of cardiac myocytes leads to heart failure, a major cause of death and disability in the developed world. Several cytosolic signaling pathways have been identified that transduce prohypertrophic signals, but to date, little work has focused on signaling pathways that might negatively regulate hypertrophy. Herein, we report that glycogen synthase kinase-3beta (GSK-3beta), a protein kinase previously implicated in processes as diverse as development and tumorigenesis, is inactivated by hypertrophic stimuli via a phosphoinositide 3-kinase-dependent protein kinase that phosphorylates GSK-3beta on ser 9. Using adenovirus-mediated gene transfer of GSK-3beta containing a ser 9 to alanine mutation, which prevents inactivation by hypertrophic stimuli, we demonstrate that inactivation of GSK-3beta is required for cardiomyocytes to undergo hypertrophy. Furthermore, our data suggest that GSK-3beta regulates the hypertrophic response, at least in part, by modulating the nuclear/cytoplasmic partitioning of a member of the nuclear factor of activated T cells family of transcription factors. The identification of GSK-3beta as a transducer of antihypertrophic signals suggests that novel therapeutic strategies to treat hypertrophic diseases of the heart could be designed that target components of the GSK-3 pathway.

Sarcoidosis and the kidney: not only the granulomatous interstitial nephritis.

Renal involvement in sarcoidosis displays a wide range of manifestations, and kidney dysfunction may involve all three mechanisms of renal failure. We report a new case of systemic sarcoidosis presenting as a severe renal failure due to hypercalcemia, sarcoidosis-related bilateral nephrolithiasis and granulomatous interstitial nephritis. A prostate adenocarcinoma was also diagnosed, but has to be regarded as an unrelated disease.

BK polyomavirus in the urine for follow-up of kidney transplant recipients.

OBJECTIVES: After kidney transplantation, human BK polyomavirus (BKPyV) can induce a progressive disease, in three stages: viruria, viraemia, and then nephropathy after a few months of viral replication. Therapeutic intervention is recommended when BKPyV is detected in the plasma. The objective of our study was to assess urinary BKPyV nucleic acid test as a predictor for developing viraemia. METHODS: We first defined a viruria threshold based on 393 time-matched urine and plasma samples collected after kidney transplantation; to validate this threshold, we followed-up a cohort of 236 kidney transplant patients. RESULTS: A BKPyV viruria threshold of 6.71 log10 copies/mL best discriminated between plasma-positive and plasma-negative patients (sensitivity 90.9% (95% CI 86.5-95); specificity 90.3% (95% CI 86.3-94.3); area under the curve 0.953 (95% CI 0.933-0.974). In the validation cohort, the risk of developing BKPyV viraemia at 1 year was 16.5% (39/236) and rose to 90.7% (39/43) if BKPyV viruria remained above the threshold of 6.71 for more than 1 month. CONCLUSIONS: Sustained BKPyV viruria is a reliable, early marker of patients at high risk of developing BKPyV viraemia. This marker should alert the clinician early, and thus allow timely therapeutic intervention.

PRODIG (Prevention of new onset diabetes after transplantation by a short term treatment of Vildagliptin in the early renal post-transplant period) study: study protocol for a randomized controlled study.

BACKGROUND: Post-transplant diabetes is a frequent and serious complication of kidney transplantation. There is currently no treatment to prevent or delay the disease. Nevertheless, identification of risk factors make it possible to target a population at risk of developing de novo diabetes. We hypothesized that a short-term treatment with vildagliptin may prevent new onset diabetes after transplantation (NODAT) in high-risk patients. METHODS/DESIGN: This is a multicenter, double-blind, placebo-controlled randomized clinical trial. Patients undergoing first kidney transplantation will be included from ten French transplant centers. Included patients will be randomized (1:1) to receive either vildagliptin 100 or 50 mg/day (depending on glomerular filtration rate) during 2 months (the first dose being administered before entering the operating theatres) or placebo. Additional antidiabetic therapy could be administered according to glycemic control. The primary outcome is the proportion of diabetic patients 1 year after transplantation, defined as patients receiving a diabetic treatment, or having a fasting glucose above 7 mmol/l, and/or with an abnormal oral glucose tolerance test. Secondary outcomes include glycated hemoglobin, the occurrence of acute rejection, infection, graft loss and patient death at 3 months, 6 months, and 12 months after transplantation. Outcomes will be correlated to clinical and general characteristics of the patient, cardiovascular history, nephropathy, dialysis history, transplantation data, biological data, health-related quality of life, and the cost-effectiveness of prevention of diabetes with vildagliptin. DISCUSSION: We have scarce data on the pharmacological prevention of post-transplant diabetes. If our hypothesis is verified, our results will have a direct application in clinical practice and could limit diabetes-associated morbidity, reduce cardiovascular complications, increase quality of life of renal transplant patients, and consequently promote graft and patient survival. Our results may possibly serve for non-transplant patients carrying a high-risk of diabetes associated with other co-morbidities. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02849899 . Registered on 8 February 2016.

A trial comparing local pain after subcutaneous injection of epoetin-beta versus darbepoetin-alpha in healthy volunteers.

BACKGROUND: The aim of this study was to compare local pain experienced with subcutaneous (s.c.) injection of epoetin-beta vs. darbepoetin-alpha. METHODS: 40 healthy volunteers were enrolled into this single-blind, crossover study. After receiving an injection of placebo, individuals were randomized to receive s.c. injections of epoetin-beta 6,000 IU (0.3 ml) or darbepoetin-alpha 30 mg (0.3 ml), with a 1-week washout period between injections. Local pain was evaluated using a Visual Analog Scale (VAS) and a 6-item Verbal Rating Scale (VRS) immediately after (T0) and 1 h after injection (T1). RESULTS: The respective mean (standard deviation) and median (range) VAS values at T0 were 1.2 (1.7) and 0.5 (0.0 - 6.9) for epoetin-beta vs. 2.8 (2.4) and 1.9 (0.0 - 9.0) for darbepoetin-alpha (p < 0.0001). At T0, VRS scores demonstrated that 51% of individuals experienced no pain after epoetin- injection compared with 16% of those receiving darbepoetin-alpha. The percentage of individuals perceiving moderate or important pain was significantly greater with darbepoetin-alpha (38%) compared with epoetin-beta (5%, p = 0.0005) and placebo (14%). Pain evaluation at T1 showed no difference between treatment groups. Local tolerance was excellent except for a small hematoma with epoetin- at T1 and with darbepoetin-alpha at T0 which persisted at T1. CONCLUSION: In healthy volunteers, s.c. injection of epoetin-beta was significantly less painful than with darbepoetin-alpha and comparable with placebo. No significant pain was apparent at T1 in any group.

Role of the stress-activated protein kinases in endothelin-induced cardiomyocyte hypertrophy.

The signal transduction pathways governing the hypertrophic response of cardiomyocytes are not well defined. Constitutive activation of the stress-activated protein kinase (SAPK) family of mitogen-activated protein (MAP) kinases or another stress-response MAP kinase, p38, by overexpression of activated mutants of various components of the pathways is sufficient to induce a hypertrophic response in cardiomyocytes, but it is not clear what role these pathways play in the response to physiologically relevant hypertrophic stimuli. To determine the role of the SAPKs in the hypertrophic response, we used adenovirus-mediated gene transfer of SAPK/ERK kinase-1 (KR) [SEK-1(KR)], a dominant inhibitory mutant of SEK-1, the immediate upstream activator of the SAPKs, to block signal transmission down the SAPK pathway in response to the potent hypertrophic agent, endothelin-1 (ET-1). SEK-1(KR) completely inhibited ET-1-induced SAPK activation without affecting activation of the other MAP kinases implicated in the hypertrophic response, p38 and extracellular signal-regulated protein kinases (ERK)-1/ERK-2. Expression of SEK-1(KR) markedly inhibited the ET-1-induced increase in protein synthesis. In contrast, the MAPK/ERK kinase inhibitor, PD98059, which blocks ERK activation, and the p38 inhibitor, SB203580, had no effect on ET-1-induced protein synthesis. ET-1 also induced a significant increase in atrial natriuretic factor mRNA expression as well as in the percentage of cells with highly organized sarcomeres, responses which were also blocked by expression of SEK-1(KR). In summary, inhibiting activation of the SAPK pathway abrogated the hypertrophic response to ET-1. These data are the first demonstration that the SAPKs are necessary for the development of agonist-induced cardiomyocyte hypertrophy, and suggest that in response to ET-1, they transduce critical signals governing the hypertrophic response.

Cytosolic phospholipase A(2) regulates golgi structure and modulates intracellular trafficking of membrane proteins.

The Golgi complex and the trans-Golgi network are critical cellular organelles involved in the endocytic and biosynthetic pathways of protein trafficking. Lipids have been implicated in the regulation of membrane-protein trafficking, vesicular fusion, and targeting. We have explored the role of cytosolic group IV phospholipase A(2) (cPLA(2)) in membrane-protein trafficking in kidney epithelial cells. Adenoviral expression of cPLA(2) in LLC-PK(1) kidney epithelial cells prevents constitutive trafficking to the plasma membrane of an aquaporin 2-green fluorescent protein chimera, with retention of the protein in the rough endoplasmic reticulum. Plasma membrane Na(+)-K(+)-ATPase alpha-subunit localization is markedly reduced in cells expressing cPLA(2), whereas the trafficking of a Cl(-)/HCO(3)(-) anion exchanger to the plasma membrane is not altered in these cells. Expression of cPLA(2) results in dispersion of giantin and beta-COP from their normal, condensed Golgi localization, and in marked disruption of the Golgi cisternae. cPLA(2) is present in Golgi fractions from noninfected LLC-PK(1) cells and rat kidney cortex. The distribution of tubulin and actin was not altered by cPLA(2), indicating that the microtubule and actin cytoskeleton remain intact. Total cellular protein synthesis is unaffected by the increase in cPLA(2) activity. Thus cPLA(2) plays an important role in determining Golgi architecture and selective control of constitutive membrane-protein trafficking in renal epithelial cells.