Objective To elucidate the molecular mechanism of sirtuin-3 (SIRT3) in regulating mitochondrial biogenesis in human renal tubular epithelial cells. Methods Cells were stimulated with different concentrations of H₂O₂ and divided into four groups: control (NC), 50 μmol/L H₂O₂, 110 μmol/L H₂O₂ and 150 μmol/L H₂O₂. SIRT3 protein expression was then measured. SIRT3 was knocked down with siRNA, and cells were further assigned to five groups: control (NC), negative-control siRNA (NCsi), SIRT3-siRNA (siSIRT3), NCsi+H₂O₂, and siSIRT3+H₂O₂. After 24 h, cellular adenosine triphosphate (ATP) and mitochondrial superoxide anion (O₂•⁻) levels were determined, together with mitochondrial expression of SIRT3, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), nuclear respiratory factor 1 (NRF1), mitochondrial transcription factor A (TFAM), superoxide dismutase 2 (SOD2), acetylated-SOD2 and adenosine monophosphate activated protein kinase α1 (AMPKα1). Results The 110 and 150 μmol/L H₂O₂ decreased SIRT3 protein (both P<0.05). ATP and mitochondrial O₂•⁻ did not differ between NC and NCsi groups (both P>0.05). Compared to the NCsi group, the siSIRT3 group exhibited elevated O₂•⁻ level, decreased SIRT3 protein and increased expression levels of SOD2 and acetylated SOD2 protein (all P<0.05). Compared to the NCsi group, the NCsi+H₂O₂ group exhibited decreased cellular ATP levels, elevated mitochondrial O₂•⁻ levels, and reduced protein expression levels of SIRT3, SOD2, TFAM, AMPKα1, PGC-1α and NRF1 (all P<0.05). Compared with the siSIRT3 group, the siSIRT3+H₂O₂ group showed a decrease in cellular ATP levels, an increase in mitochondrial O₂•⁻ levels, a decrease in SIRT3, SOD2, TFAM, AMPKα1, PGC-1α and NRF1 protein expression levels and a decrease in acetylated SOD2 protein expression levels (all P<0.05). Compared with the NCsi+H₂O₂ group, the siSIRT3+H₂O₂ group showed a decrease in cellular ATP levels, an increase in mitochondrial O₂•⁻ levels, a decrease in SIRT3, AMPKα1, PGC-1α and NRF1, TFAM protein expression levels, and an increase in SOD2 and acetylated SOD2 protein expression levels (all P<0.05). Conclusions SIRT3 promotes mitochondrial biogenesis in tubular epithelial cells via the AMPK/PGC-1α/NRF1/TFAM axis, representing a key mechanism through which SIRT3 ameliorates oxidative stress-induced mitochondrial dysfunction.

ObjectiveTo investigate the ameliorative effects and related mechanisms of the Zuogui Jiangtang Shuxin prescription （ZJSP） on glucose and lipid metabolism disorders in MKR mice with diabetic cardiomyopathy （DCM）， with a focus on elucidating its regulatory role on the adenosine monophosphate-activated protein kinase （AMPK）/forkhead box protein O1 （FoxO1）/cluster of differentiation 36 （CD36） signaling pathway and lipid deposition. MethodsFifty 8-week-old male MKR mice were fed a high-fat diet for four weeks and then intraperitoneally injected with streptozotocin （STZ） while maintaining a high-fat diet to establish a DCM model. The mice were randomly divided into the model group， the low-dose（14.43 g·kg^-1）and high-dose（28.86 g·kg^-1） ZJSP groups， and the metformin group （0.25 g·kg^-1）， with age-matched FVB mice as a normal control group. Each group received intragastric administration of normal saline or corresponding concentrations of ZJSP at equal volumes. After four weeks， fasting blood glucose （FBG） and cardiac function were measured. Blood was collected from the eyeballs under anesthesia to detect fasting insulin （FINS） and blood lipid levels. Myocardial tissue morphology was observed by hematoxylin-eosin （HE） staining， and lipid deposition in the heart was assessed using oil red O staining. Real-time quantitative polymerase chain reaction （Real-time PCR） was used to measure the mRNA expression levels of AMPK， FoxO1， and CD36 in myocardial tissues. Western blot was employed to detect the protein expression levels of AMPK， p-AMPK， FoxO1， p-FoxO1， and CD36. ResultsCompared with the control group， the model group showed significantly increased levels of FBG and FINS （P<0.01）， elevated levels of triglycerides （TG）， total cholesterol （TC）， and low-density lipoprotein cholesterol （LDL-C） （P<0.01）， and significantly decreased left ventricular ejection fraction （EF） and fractional shortening （FS） values （P<0.01）. HE staining revealed marked cardiomyocyte hypertrophy， disarray， and widened intercellular spaces in myocardial tissues. Oil Red O staining showed extensive red deposition areas and fine lipid droplet accumulation in the myocardial tissue. AMPK mRNA expression was decreased， while FoxO1 and CD36 mRNA expressions were significantly increased （P<0.01）. The p-AMPK/AMPK protein expression ratio in myocardial tissues was significantly reduced， while the p-FoxO1/FoxO1 protein expression ratio and CD36 protein expression levels were significantly increased （P<0.01）. Compared with the model group， all treatment groups exhibited significantly reduced FBG （P<0.01）， decreased FINS and blood lipid levels （TG， TC， LDL-C） （P<0.05， P<0.01）， improved cardiac function （P<0.05）， noticeable amelioration of myocardial histopathological morphology and lipid deposition， increased AMPK mRNA expression （P<0.01）， with significantly downregulated FoxO1 and CD36 mRNA expressions （P<0.01）， elevated p-AMPK/AMPK protein expression levels in myocardial tissue （P<0.05）， significantly decreased p-FoxO1/FoxO1 ratios （P<0.01）， and downregulated CD36 protein expression levels （P<0.05， P<0.01）. ConclusionZJSP exerts a protective effect on the heart in type 2 DCM of MKR mice， and its mechanism may be associated with the regulation of the AMPK/FoxO1/CD36 signaling pathway.

ObjectiveTo investigate the ameliorative effects and related mechanisms of the Zuogui Jiangtang Shuxin prescription （ZJSP） on glucose and lipid metabolism disorders in MKR mice with diabetic cardiomyopathy （DCM）， with a focus on elucidating its regulatory role on the adenosine monophosphate-activated protein kinase （AMPK）/forkhead box protein O1 （FoxO1）/cluster of differentiation 36 （CD36） signaling pathway and lipid deposition. MethodsFifty 8-week-old male MKR mice were fed a high-fat diet for four weeks and then intraperitoneally injected with streptozotocin （STZ） while maintaining a high-fat diet to establish a DCM model. The mice were randomly divided into the model group， the low-dose（14.43 g·kg^-1）and high-dose（28.86 g·kg^-1） ZJSP groups， and the metformin group （0.25 g·kg^-1）， with age-matched FVB mice as a normal control group. Each group received intragastric administration of normal saline or corresponding concentrations of ZJSP at equal volumes. After four weeks， fasting blood glucose （FBG） and cardiac function were measured. Blood was collected from the eyeballs under anesthesia to detect fasting insulin （FINS） and blood lipid levels. Myocardial tissue morphology was observed by hematoxylin-eosin （HE） staining， and lipid deposition in the heart was assessed using oil red O staining. Real-time quantitative polymerase chain reaction （Real-time PCR） was used to measure the mRNA expression levels of AMPK， FoxO1， and CD36 in myocardial tissues. Western blot was employed to detect the protein expression levels of AMPK， p-AMPK， FoxO1， p-FoxO1， and CD36. ResultsCompared with the control group， the model group showed significantly increased levels of FBG and FINS （P<0.01）， elevated levels of triglycerides （TG）， total cholesterol （TC）， and low-density lipoprotein cholesterol （LDL-C） （P<0.01）， and significantly decreased left ventricular ejection fraction （EF） and fractional shortening （FS） values （P<0.01）. HE staining revealed marked cardiomyocyte hypertrophy， disarray， and widened intercellular spaces in myocardial tissues. Oil Red O staining showed extensive red deposition areas and fine lipid droplet accumulation in the myocardial tissue. AMPK mRNA expression was decreased， while FoxO1 and CD36 mRNA expressions were significantly increased （P<0.01）. The p-AMPK/AMPK protein expression ratio in myocardial tissues was significantly reduced， while the p-FoxO1/FoxO1 protein expression ratio and CD36 protein expression levels were significantly increased （P<0.01）. Compared with the model group， all treatment groups exhibited significantly reduced FBG （P<0.01）， decreased FINS and blood lipid levels （TG， TC， LDL-C） （P<0.05， P<0.01）， improved cardiac function （P<0.05）， noticeable amelioration of myocardial histopathological morphology and lipid deposition， increased AMPK mRNA expression （P<0.01）， with significantly downregulated FoxO1 and CD36 mRNA expressions （P<0.01）， elevated p-AMPK/AMPK protein expression levels in myocardial tissue （P<0.05）， significantly decreased p-FoxO1/FoxO1 ratios （P<0.01）， and downregulated CD36 protein expression levels （P<0.05， P<0.01）. ConclusionZJSP exerts a protective effect on the heart in type 2 DCM of MKR mice， and its mechanism may be associated with the regulation of the AMPK/FoxO1/CD36 signaling pathway.

OBJECTIVE To explore the mechanism of Qiangxin decoction in the treatment of chronic heart failure （CHF） by regulating the inhibitor of nuclear factor-κB alpha/nuclear factor-κB p65 subunit （IκBα/NF-κB p65） signaling pathway-mediated M1 macrophage polarization. METHODS In animal experiments， mice were used as research subjects， and the CHF model was established via coronary artery ligation. Model mice were treated with Qiangxin decoction （21.69 g/kg） for 28 days. After intervention， pathological morphological changes of myocardial tissues and cardiomyocyte apoptosis were observed. Serum levels of inflammatory factors including tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6）， myocardial injury marker troponin I3 （TNNI3）， and macrophage-related markers F4/80 and cluster of differentiation 80 （CD80） were detected. In cell experiments， monocyte-macrophage leukemia RAW264.7 cells were induced to undergo M1 polarization by 10 ng/mL lipopolysaccharide combined with 10 ng/mL interferon-γ， followed by 48 h intervention with 10% drug-containing serum of Qiangxin decoction. After intervention， the nuclear translocation of NF-κB p65 and NF-κB p50 was observed. The positive rate of CD80 in cells was measured. The mRNA expression of inflammatory factors including IL-1β， IL-6， IL-8， IL-18， TNF-α， inducible nitric oxide synthase （iNOS）， cyclooxygenase-2 （COX2）， C-C motif chemokine receptor 7 isoform 2 （CCR7-2）， as well as the expression levels of proteins related to the IκBα/NF-κB p65 signaling pathway were detected. RESULTS Animal experimental results showed that Qiangxin decoction alleviated myocardial fibrosis in mice， and significantly reduced the cardiomyocyte apoptosis rate， serum levels of TNF-α and IL-6， as well as the protein expression of TNNI3， F4/80 and CD80 in myocardial tissues （P＜0.05）. Cell experimental results indicated that Qiangxin decoction significantly suppressed the nuclear translocation of NF-κB p65 and NF-κB p50 （P＜0.05）. It significantly decreased the CD80 positive rate， mRNA levels of IL-1β， IL-6， IL-8， IL-18， TNF-α， iNOS， COX2 and CCR7-2， total and nuclear expression of NF-κB p65， total， nuclear and cytoplasmic expression of phosphorylated NF-κB p65， total expression of phosphorylated IκBα （P＜0.05）. Meanwhile， it significantly elevated the total expression of IκBα and cytoplasmic expression of NF-κB p65 （P＜0.05）. CONCLUSIONS Qiangxin decoction can inhibit the activity of the IκBα/NF-κB p65 signaling pathway， reduce the release of pro-inflammatory factors， thereby restraining M1 macrophage polarization， mitigating myocardial fibrosis， and ultimately exerting therapeutic effects against CHF.

ObjectiveTo investigate the mechanism by which Luoshi Neiyi prescription treats endometriosis （EMs） through the Toll-like receptor 4 （TLR4）/nuclear factor-κB （NF-κB） signaling pathway. MethodsAnimal experiments were conducted with 50 female SD rats， which were randomized into a sham operation group （10 rats） and a modeling group （40 rats）. An autologous endometrial transplantation method was used for the modeling of EMs. The 36 successfully modeled rats were randomly allocated into four groups （n=9 each）： The model group， the low-dose （7.87 g·kg^-1） Luoshi Neiyi prescription group， the high-dose （15.74 g·kg^-1） Luoshi Neiyi prescription group， and the dienogest （0.20 mg·kg^-1） group. The physiological status and ectopic lesion volumes of rats in each group were observed. Hematoxylin-eosin （HE） staining was used to observe the morphology of the eutopic endometrial tissue. Enzyme-linked immunosorbent assay （ELISA） was employed to measure the levels of inflammatory factors including interleukin-1β （IL-1β） and prostaglandin E₂ （PGE₂） in the serum of EMs rats. Immunohistochemistry was used to detect the expression of matrix metalloproteinase-9 （MMP-9） and vascular endothelial growth factor A （VEGFA） in the eutopic endometrial tissue. Western blot was adopted to determine the protein levels of TLR4， myeloid differentiation factor 88 （MyD88）， phosphorylated nuclear factor-κB （p-NF-κB）/NF-κB， MMP-9， and VEGFA in the eutopic endometrial tissue. In the cell experiments， the cell-counting kit-8 （CCK-8） assay was employed to screen the optimal concentration of Luoshi Neiyi prescription-containing serum， and a scratch assay was performed to assess the migration ability of iheESCs cells. Interventions with Luoshi Neiyi prescription-containing serum， resatorvid （TAK-242， a TLR4 inhibitor）， and lipopolysaccharides （LPS， a TLR4 agonist） were conducted， and Western blot was used to detect the expression of proteins related to the TLR4/NF-κB signaling pathway. ResultsThis experiment successfully replicated 36 EMs rat models. Compared with the sham operation group， the model group exhibited visible ectopic lesions on the abdominal wall and an increase in the writhing response score （P<0.01）. Furthermore， HE staining revealed the model group exhibited a thickened eutopic epithelium， stromal cell disarrangement， and evident infiltration of inflammatory cells. In addition， the model group showed elevated serum levels of IL-1β and PGE₂ （P<0.05， P<0.01）， increased positive expression of MMP-9 and VEGFA in the ectopic endometrial tissue （P<0.01）， and up-regulated protein levels of TLR4， MyD88， p-NF-κB/NF-κB， MMP-9， and VEGFA in the ectopic endometrial tissue （P<0.05， P<0.01）. Compared with the model group， all treatment groups exhibited a reduction in the ectopic lesion volume （P<0.01）. Furthermore， the writhing response scores were decreased in the high-dose Luoshi Neiyi prescription group and the dienogest group （P<0.05， P<0.01）. The pathological state of the ectopic endometrial tissue was alleviated to varying degrees in the treatment groups. Low-dose Luoshi Neiyi prescription reduced serum PGE₂ levels， and high-dose Luoshi Neiyi prescription and dienogest decreased serum IL-1β and PGE₂ levels in EMs rats （P<0.05， P<0.01）. The treatment groups showed decreased positive expression of MMP-9 and VEGFA in the ectopic endometrial tissue （P<0.05， P<0.01） and down-regulated protein levels of TLR4， MyD88， p-NF-κB/NF-κB， MMP-9， and VEGFA in the ectopic endometrial tissue （P<0.05， P<0.01）. The cell experiments showed that 5%， 10%， and 20% Luoshi Neiyi prescription-containing sera significantly reduced the viability and inhibited the migration of iheESCs. Compared with the control group， 5%， 10%， and 20% Luoshi Neiyi prescription-containing serum groups and the TAK-242 group showed reduced protein levels of TLR4， MyD88， p-NF-κB/NF-κB， MMP-9， and VEGFA （P<0.01）. Compared with the control group， the LPS group showed increased expression of the above proteins （P<0.01）. Compared with the LPS group， the LPS+5%， 10%， and 20% Luoshi Neiyi prescription-containing serum groups showed reduced expression of the above proteins （P<0.05， P<0.01）. ConclusionLuoshi Neiyi prescription may modulate the TLR4/NF-κB signaling pathway to reduce the inflammatory response and histopathological damage in the eutopic endometrium and suppress the adhesive， invasive， and angiogenic biological processes in the ectopic endometrial tissue， thereby exerting its therapeutic effect on EMs.

Autoimmune pancreatitis is a special type of chronic pancreatitis that can lead to abnormal pancreatic exocrine function in patients. Autoimmune pancreatitis comorbid with pancreatic exocrine insufficiency has a complex pathogenesis， and there is limited research on this topic， leading to the lack of understanding of such patients in clinical practice. This article introduces the epidemiology of autoimmune pancreatitis， briefly describes the pathogenesis of pancreatic exocrine insufficiency caused by autoimmune pancreatitis， and summarizes the various detection methods for pancreatic exocrine function， nutritional assessments， lifestyle management， and drug therapy， in order to strengthen the understanding of autoimmune pancreatitis comorbid with pancreatic exocrine insufficiency and improve the clinical diagnosis and treatment of pancreatic exocrine insufficiency.

Intraoperative cell salvage (IOCS) has been widely applied as an important blood conservation measure in surgical operations. However, there is currently a lack of clinical practice guidelines for the implementation of IOCS in patients with malignant tumors. This report aims to provide clinicians with recommendations on the use of IOCS in patients with malignant tumors based on the review and assessment of the existed evidence. Data were derived from databases such as PubMed, Embase, the Cochrane Library and Wanfang. The guideline development team formulated recommendations based on the quality of evidence, balance of benefits and harms, patient preferences, and health economic assessments. This study constructed seven major clinical questions. The main conclusions of this guideline are as follows: 1) Compared with no perioperative allogeneic blood transfusion (NPABT), perioperative allogeneic blood transfusion (PABT) leads to a more unfavorable prognosis in cancer patients (Recommended); 2) Compared with the transfusion of allogeneic blood or no transfusion, IOCS does not lead to a more unfavorable prognosis in cancer patients (Recommended); 3) The implementation of IOCS in cancer patients is economically feasible (Recommended); 4) Leukocyte depletion filters (LDF) should be used when implementing IOCS in cancer patients (Strongly Recommended); 5) Irradiation treatment of autologous blood to be reinfused can be used when implementing IOCS in cancer patients (Recommended); 6) A careful assessment of the condition of cancer patients (meeting indications and excluding contraindications) should be conducted before implementing IOCS (Strongly Recommended); 7) Informed consent from cancer patients should be obtained when implementing IOCS, with a thorough pre-assessment of the patient's condition and the likelihood of blood loss, adherence to standardized internally audited management procedures, meeting corresponding conditions, and obtaining corresponding qualifications (Recommended). In brief, current evidence indicates that IOCS can be implemented for some malignant tumor patients who need allogeneic blood transfusion after physician full evaluation, and LDF or irradiation should be used during the implementation process.

Ferroptosis, a programmed cell death modality discovered and defined in the last decade, is primarily induced by iron-dependent lipid peroxidation. At present, it has been found that ferroptosis is involved in various physiological functions such as immune regulation, growth and development, aging, and tumor suppression. Especially its role in tumor biology has attracted extensive attention and research. Breast cancer is one of the most common female tumors, characterized by high heterogeneity and complex genetic background. Triple negative breast cancer (TNBC) is a special type of breast cancer, which lacks conventional breast cancer treatment targets and is prone to drug resistance to existing chemotherapy drugs and has a low cure rate after progression and metastasis. There is an urgent need to find new targets or develop new drugs. With the increase of studies on promoting ferroptosis in breast cancer, it has gradually attracted attention as a treatment strategy for breast cancer. Some studies have found that certain compounds and natural products can act on TNBC, promote their ferroptosis, inhibit cancer cells proliferation, enhance sensitivity to radiotherapy, and improve resistance to chemotherapy drugs. To promote the study of ferroptosis in TNBC, this article summarized and reviewed the compounds and natural products that induce ferroptosis in TNBC and their mechanisms of action. We started with the exploration of the pathways of ferroptosis, with particular attention to the System X_c^--cystine-GPX4 pathway and iron metabolism. Then, a series of compounds, including sulfasalazine (SAS), metformin, and statins, were described in terms of how they interact with cells to deplete glutathione (GSH), thereby inhibiting the activity of glutathione peroxidase 4 (GPX4) and preventing the production of lipid peroxidases. The disruption of the cellular defense against oxidative stress ultimately results in the death of TNBC cells. We have also our focus to the realm of natural products, exploring the therapeutic potential of traditional Chinese medicine extracts for TNBC. These herbal extracts exhibit multi-target effects and good safety, and have shown promising capabilities in inducing ferroptosis in TNBC cells. We believe that further exploration and characterization of these natural compounds could lead to the development of a new generation of cancer therapeutics. In addition to traditional chemotherapy, we discussed the role of drug delivery systems in enhancing the efficacy and reducing the toxicity of ferroptosis inducers. Nanoparticles such as exosomes and metal-organic frameworks (MOFs) can improve the solubility and bioavailability of these compounds, thereby expanding their therapeutic potential while minimizing systemic side effects. Although preclinical data on ferroptosis inducers are relatively robust, their translation into clinical practice remains in its early stages. We also emphasize the urgent need for more in-depth and comprehensive research to understand the complex mechanisms of ferroptosis in TNBC. This is crucial for the rational design and development of clinical trials, as well as for leveraging ferroptosis to improve patient outcomes. Hoping the above summarize and review could provide references for the research and development of lead compounds for the treatment for TNBC.

By reviewing the practice and current situation of the standardized training for naval surgical residents,in combination with the practice of the standardized training for resident doctors in Shanghai,this paper sums up the existing experience and explores clinical teaching,management and patterns of standardized training for naval residents based on the post competence.The aim of the study is to strengthen naval primary medical care,enhance trainees'working competence and medical support capabilities,improve the quality and level of standardized training for naval residents,so as to provide reference for the further development of the training strategy of naval officers.

Objective To analyze the effect of Hsa-circ-0101216 on gemcitabine(GEM)chemotherapy resistance in pancreatic cancer and its mechanism.Methods Differentially expressed circRNAs between GEM-resistant pancreatic cancer cells and parent cells were screened using the GEO database.Pancreatic cancer GEM resistant cell lines(BxPC-3-GEM and Capan-1-GEM)were constructed by intermittent concentration gradient method.qRT-PCR was used to detect the expression of Hsa-circ-0101216 in cells.GEM resistant pancreatic cancer cell lines were taken and divided into sh-circ-0101216 group(knockdown of circ-0101216),sh-NC group(transfected with sh-NC),and blank control group(untreated).CCK-8 assay and EdU proliferation assay were used to detect the half inhibitory concentration(IC50)of GEM and proliferation ability of cells in each group.Western blotting was performed to detect the expression of multidrug resistance-related protein 1(MRP1),breast cancer resistance protein(BCRP),and human equilibrative nucleoside transporter-1(hENT-1).A subcutaneous xenograft tumor model of human pancreatic cancer in nude mice was constructed,and sh-NC+GEM group and sh-circ-0101216+GEM group(n=6)were set up.The volume and weight of xenograft tumor in nude mice were compared between the two groups.Western blotting and immunohistochemistry were used to detect the expression of MRP1,BCRP,and hENT-1 proteins in xenograft tumor tissues,and EDU proliferation assay was used to detect the proliferation ability of tumor cells.Results The GEO database screening showed that Hsa-circ-0101216 was up-regulated in GEM-resistant pancreatic cancer cell lines.Pancreatic cancer GEM-resistant cell lines were successfully constructed,and the expression levels of Hsa-circ-0101216 and the IC50 value in GEM-resistant pancreatic cancer cells BxPC-3-GEM and Capan-1-GEM were significantly higher than those in parental cells(P<0.05).In sh-circ-0101216 group,the IC50 values of GEM,cell viability,EdU positivity rate,and the expression levels of MRP1 and BCRP proteins in GEM-resistant pancreatic cancer cells BxPC-3-GEM and Capan-1-GEM were significantly lower than those in blank control group and sh-NC group,while the expression level of hENT-1 protein was significantly higher(P<0.05 or P<0.001).In sh-circ-0101216+GEM group,the weight and volume of subcutaneous xenograft tumors in nude mice,the expression levels and positive expression rates of MRP1 and BCRP proteins in tumor tissues,and the EdU positive rate were significantly lower than those in sh-NC+GEM group,while the expression level and positive expression rate of hENT-1 protein were significantly higher(P<0.05).Conclusions Hsa-circ-0101216 is highly expressed in GEM-resistant pancreatic cancer cell lines.Its knockdown can inhibit the proliferation of pancreatic cancer cells and enhance the chemosensitivity of pancreatic cancer cells to GEM.The mechanism may be related to the regulation of transmembrane transporter protein expression.