Repurposing cinacalcet suppresses multidrug-resistant Staphylococcus aureus by disruption of cell membrane and inhibits biofilm by targeting IcaR.

BACKGROUND: MDR Staphylococcus aureus infections, along with the severity of biofilm-associated infections, continue to threaten human health to a great extent. It necessitates the urgent development of novel antimicrobial and antibiofilm agents. OBJECTIVES: To reveal the mechanism and target of cinacalcet as an antibacterial and antimicrobial agent for S. aureus. METHODS: Screening of non-antibiotic drugs for antibacterial and antibiofilm properties was conducted using a small-molecule drug library. In vivo efficacy was assessed through animal models, and the antibacterial mechanism was studied using quantitative proteomics, biochemical assays, LiP-SMap, BLI detection and gene knockout techniques. RESULTS: Cinacalcet, an FDA-approved drug, demonstrated antibacterial and antibiofilm activity against S. aureus, with less observed development of bacterial resistance. Importantly, cinacalcet significantly improved survival in a pneumonia model and bacterial clearance in a biofilm infection model. Moreover, the antibacterial mechanism of cinacalcet mainly involves the destruction of membrane-targeted structures, alteration of energy metabolism, and production of reactive oxygen species (ROS). Cinacalcet was found to target IcaR, inhibiting biofilm formation through the negative regulation of IcaADBC. CONCLUSIONS: The findings suggest that cinacalcet has potential for repurposing as a therapeutic agent for MDR S. aureus infections and associated biofilms, warranting further investigation.

Differences between long- and short-wavelength light-induced retinal damage and the role of PARP-1 in retinal injury induced by blue light.

Photobiomodulation (PBM) therapy uses light of different wavelengths to treat various retinal degeneration diseases, but the potential damage to the retina caused by long-term light irradiation is still unclear. This study were designed to detect the difference between long- and short-wavelength light (650-nm red light and 450-nm blue light, 2.55 mW/cm2, reference intensity in PBM)-induced injury. In addition, a comparative study was conducted to investigate the differences in retinal light damage induced by different irradiation protocols (short periods of repeated irradiation and a long period of constant irradiation). Furthermore, the protective role of PARP-1 inhibition on the molecular mechanism of blue light-induced injury was confirmed by a gene knockdown technique or a specific inhibitor through in vitro and in vivo experiments. The results showed that the susceptibility to retinal damage caused by irradiation with long- and short-wavelength light is different. Shorter wavelength lights, such as blue light, induce more severe retinal damage, while the retina exhibits better resistance to longer wavelength lights, such as red light. In addition, repeated irradiation for short periods induces less retinal damage than constant exposure over a long period. PARP-1 plays a critical role in the molecular mechanism of blue light-induced damage in photoreceptors and retina, and inhibiting PARP-1 can significantly protect the retina against blue light damage. This study lays an experimental foundation for assessing the safety of phototherapy products and for developing target drugs to protect the retina from light damage.

Implantable sustained-release drug delivery systems: a revolution for ocular therapeutics.

PURPOSE: Due to the inimitable anatomical structure of the eyeball and various physiological barriers, conventional ocular local administration is often complicated by apparent shortcomings, such as limited bioavailability and short drug retention. Thus, developing methods for sustainable, safe and efficient drug delivery to ocular target sites has long been an urgent need. This study briefly summarizes the barriers to ocular drug administration and various ocular drug delivery routes and highlights recent progress in ocular implantable sustained-release drug delivery systems (DDSs) to provide literature evidence for developing novel ocular implants for sustained drug delivery. METHODS: We conducted a comprehensive search of studies on ocular implantable sustained-release DDSs in PubMed and Web of Science using the following keywords: ocular, implantable and drug delivery system. More than 400 papers were extracted. Publications focused on sustained and controlled drug release were primarily considered. Experimental articles involving DDSs that cannot be implanted into the eye through surgeries and cannot be inserted into ocular tissues in solid form were excluded. Approximately 143 publications were reviewed to summarize the most current information on the subject. RESULTS: In recent years, numerous ocular sustained-release DDSs using lipids, nanoparticles and hydrogels as carriers have emerged. With unique properties and systematic design, ocular implantable sustained-release DDSs are able to continuously maintain drug release, effectively sustain the therapeutic concentration in target tissues, and substantially enhance the therapeutic efficacy. Nevertheless, few ocular implantable sustained-release DDSs have been available in clinical use. CONCLUSIONS: Ocular implantable sustained-release DDSs have become a new focus in the field of ocular drug development through unique designs and improvements in the materials of drug carriers, administration methods and dosage forms. With more ocular implantable sustained-release DDSs being commercialized, ocular therapeutics may be revolutionized.

[Management of chronic kidney disease guided by the theory of Traditional Chinese Medicine: an experimental study].

OBJECTIVE: To determine the impact of Traditional Chinese Medicine on patients with chronic kidney disease (CKD). METHODS: A total of 225 CKD patients in an outpatient department were recruited for this study, among whom 170 received regular Western and Chinese medicine treatments (control group) and 55 received treatments guided by the theory of Traditional Chinese Medicine (experimental group). The effectiveness of the treatments was determined through a pre-post comparison. RESULTS: Significant pre-intervention differences in age (P < 0.01), stage of glomerular filtration rate (GFR) (P = 0.007) and urine protein (P < 0.01) were found between the two groups of patients. But age, gender and proteinuria were not significant predictors on clinical outcomes of the patients in the multivariate regression models. The experimental group had a greater level of decrease in blood urea nitrogen (P < 0.01) and serum creatine (P < 0. 01) than the control group. No significant differences between the groups were found in changes of uric acid (P = 0.475), urine protein (P = 0.058), urine red cells (P = 0.577), and urine white cells (P = 0.01). A greater level of increase in estimated glomerular filtration rate was found in the experimental group compared with the control (P < 0.001). The multivariate linear regression analysis identified group (B = 0.395, P < 0.001) and stage of GFR (B = 0.165, P = 0.008) as significant predictors on the outcomes of treatment. CONCLUSION: The treatment of CKD patients guided by the theory of Traditional Chinese Medicine can improve renal function through influencing glomerular filtration rate. The effect is more prominent than the regular treatment regime.

Promotion of axon regeneration and protection on injured retinal ganglion cells by rCXCL2.

BACKGROUND: In addition to rescuing injured retinal ganglion cells (RGCs) by stimulating the intrinsic growth ability of damaged RGCs in various retinal/optic neuropathies, increasing evidence has shown that the external microenvironmental factors also play a crucial role in restoring the survival of RGCs by promoting the regrowth of RGC axons, especially inflammatory factors. In this study, we aimed to screen out the underlying inflammatory factor involved in the signaling of staurosporine (STS)-induced axon regeneration and verify its role in the protection of RGCs and the promotion of axon regrowth. METHODS: We performed transcriptome RNA sequencing for STS induction models in vitro and analyzed the differentially expressed genes. After targeting the key gene, we verified the role of the candidate factor in RGC protection and promotion of axon regeneration in vivo with two RGC-injured animal models (optic nerve crush, ONC; retinal N-methyl-D-aspartate, NMDA damage) by using cholera toxin subunit B anterograde axon tracing and specific immunostaining of RGCs. RESULTS: We found that a series of inflammatory genes expressed upregulated in the signaling of STS-induced axon regrowth and we targeted the candidate CXCL2 gene since the level of the chemokine CXCL2 gene elevated significantly among the top upregulated genes. We further demonstrated that intravitreal injection of rCXCL2 robustly promoted axon regeneration and significantly improved RGC survival in ONC-injured mice in vivo. However, different from its role in ONC model, the intravitreal injection of rCXCL2 was able to simply protect RGCs against NMDA-induced excitotoxicity in mouse retina and maintain the long-distance projection of RGC axons, yet failed to promote significant axon regeneration. CONCLUSIONS: We provide the first in vivo evidence that CXCL2, as an inflammatory factor, is a key regulator in the axon regeneration and neuroprotection of RGCs. Our comparative study may facilitate deciphering the exact molecular mechanisms of RGC axon regeneration and developing high-potency targeted drugs.

[Investigate the effects of compound radix notoginseng on renal interstitial fibrosis and kidney-targeting treatment].

OBJECTIVE: Investigate the effects of compound Radix Notoginseng on renal interstitial fibrosis and kidney-targeting treatment. METHODS: 100 healthy Sprague-Dawley rats were randomly divided into 5 groups: Unilateral ureteral obstruction (UUO) group, sham-operation (SOR) group, Radix Notoginseng (RN) group, compound Radix Notoginseng (CRN) group and Losartan (ARB) group. After operation, RN, CRN and ARB groups were intragastric administrated with RN (3 mL/d), CRN (3 mL/d) and ARB [20 mg/(kg x d)] respectively. Each group randomly included 18 rats for statistical analysis. The histological changes of renal interstitial tissues were observed by HE, Masson and PAS staining. Total kidney collagen content was determined by measuring the amount of hydroxyproline. The mRNA of alpha-SMA, collagen I and fibronectin were reverse transcribed and quantified by real-time PCR. The expression of alpha-SMA protein was assessed by immunohistochemistry and Western blot analysis. RESULTS: In UUO model, the obstructed kidney showed typical features of renal tubulointerstitial fibrosis, such as severe tubular loss, dilation, atrophy, infiltration of inflammatory cells, interstitial matrix deposition (P < 0.05). Partial correlation assay showed that the expression of alpha-SMA was related to the renal tubular injury (r = 0.55; P < 0.05). Administration of RN, CRN and ARB improved tubulointerstitial damage and collagen matrix accumulation induced by UUO in different degree. The expression of the alpha-SMA at mRNA and protein levels were significantly increased in the UUO group (P < 0.05), which was also suppressed by treatment with RN, CRN and ARB in different degree. Moreover, more effective role in preventing fibrosis was observed in CRN group than when compared with that of RN group. CONCLUSION: RN and CRN can inhibit UUO-induced renal interstitial fibrosis in rats, and CRN treatment is more effective than RN in reducing interstitial fibrosis.

[Effects of astragaloside IV on delaying kidney aging and its mechanisms].

OBJECTIVE: To investigate the mechanisms of Astragaloside Ⅳ on inhibiting apoptosis and delaying kidney aging in rats by regulating SIRT1/p53 signaling pathway. METHODS: The aging model was established by subcutaneous injection of D-galactose 200 mg/(kg·d). SPF-grade healthy male SD rats were randomly divided into 4 groups: normal control group (intragastric infusion of 5 ml/(kg·d) normal saline), aging model group (intragastric infusion of 5 ml/(kg·d) normal saline), Astragaloside IV group (intragastric infusion of 40 mg/(kg·d) Astragaloside IV),and SRT1720 group( intragastric infusion of 20 mg/(kg·d) SRT1720), with 10 rats in each group. After 8 weeks, the serum samples of rats were collected to detect the levels of renal function (creatinine and urea nitrogen) and senescent associated secretory phenotype (TGF-ß and IL-6) by ELISA. The renal tissues of rats were obtained for HE and Masson staining. The protein and mRNA expressions of SIRT1, p53, Bcl-2, Bax, p21 and pRb were detected by Western blot and RT-PCR. RESULTS: Serum creatinine and urea nitrogen levels in the aging model group were higher than those in the normal group, but there was no significant difference in each group (P＞0.05). The serum levels of TGF-ß and IL-6 in the aging model group were higher than those in the normal group (P＜0.05), and which in the Astragaloside IV group and SRT1720 group were lower than those in the model group (P＜0.05). There was no significant differences between Astragaloside IV group and SRT1720 group (P＞0.05). The results of pathological staining of renal tissues showed that, compared with the normal group, the renal tubules dilated, local atrophy, infiltration of inflammatory cells and proliferation of collagen fibers were observed in the aging model group. Compared with the aging model group, the pathological changes were alleviated in Astragaloside IV group and SRT1720 group. The results of Western blot and RT-PCR showed that, compared with the normal group, the protein and mRNA expressions of SIRT1 and pRb in the renal tissue of the aging group were decreased, the protein expression of Bcl-2 was decreased(P＜0.05), and the protein and mRNA expressions of p53 and p21 were increased, the protein expression of Bax was increased(P＜0.05). Compared with the aging group, Astragaloside IV and SRT1720 improved the above-mentioned indexes (P＜0.05). CONCLUSION: Astragaloside IV can delay kidney aging by regulating the SIRT1/p53 signaling pathway.

Experimental models and examination methods of retinal detachment.

Retinal detachment refers to the separation of the retinal neuroepithelium and pigment epithelium, usually involving the death of photoreceptor cells. Severe detachment may lead to permanent visual impairment if not treated properly and promptly. According to the underlying causes, retinal detachment falls into one of three categories: exudative retinal detachment, traction detachment, and rhegmatogenous retinal detachment. Like many other diseases, it is difficult to study the pathophysiology of retinal detachment directly in humans, because the human retinal tissues are precious, scarce and non-regenerative; thus, establishing experimental models that better mimic the disease is necessary. In this review, we summarize the existing models of the three categories of retinal detachment both in vivo and in vitro, along with an overview of their examination methods and the major strengths and weaknesses of each model.

Effects of Probiotic Preparations on Inflammatory Cytokines in Chronic Kidney Disease Patients: A Systematic Review and Meta-Analysis.

OBJECTIVE: To summarize and assess the effects of probiotic preparations on inflammatory cytokine levels in patients with Chronic Kidney Disease (CKD). METHODS: We searched through the PubMed, Cochrane Library, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature Database (CBM), and Wan Fang databases for Randomized Controlled Trials (RCTs) that report the impact of probiotic preparations on inflammatory cytokines in CKD patients. Outcomes were composed of serum levels of CReactive Protein (CRP), Interleukin 6 (IL-6), Tumor Necrosis Factor-α (TNF-α), serum urea, creatinine, uric acid, Para-Cresol Sulfate (PCS), and Indoxyl-Sulfate (IS). The Mean Differences (MDs) with 95% Confidence Intervals (CIs) were considered as effect estimates. Sensitivity analysis and Egger's linear regression test were performed to evaluate the stability of results and publication bias. This study was registered with PROSPERO number CRD42020176557. RESULTS AND DISCUSSION: Sixteen studies met the inclusion criteria. Evidence showed that serum CRP levels were decreased in the intervention group (WMD, -12.29, 95% CI, -16.41 to -8.16, p = 0). The IL-6 was significantly reduced only in the prebiotic group (SMD, -0.73, 95% CI, -1.3 to -0.16, p = 0.012). However, no reduction was observed in TNF-α (SMD, -0.07, 95% CI, -0.51 to 0.38, p = 0.772). Moreover, there was no significant change in serum uremic toxin, including creatine, urea, uric acid, PCS, and IS. CONCLUSION: Probiotic preparations decrease the serum levels of inflammatory cytokines in CKD patients but do not affect the serum uremic toxin levels. The results of this meta-analysis suggest essential guidance for treatment decisions in clinical practice.

Autophagy in Age-Related Macular Degeneration: A Regulatory Mechanism of Oxidative Stress.

Age-related macular degeneration (AMD) is a leading cause of severe visual loss and irreversible blindness in the elderly population worldwide. Retinal pigment epithelial (RPE) cells are the major site of pathological alterations in AMD. They are responsible for the phagocytosis of shed photoreceptor outer segments (POSs) and clearance of cellular waste under physiological conditions. Age-related, cumulative oxidative stimuli contribute to the pathogenesis of AMD. Excessive oxidative stress induces RPE cell degeneration and incomplete digestion of POSs, leading to the continuous accumulation of cellular waste (such as lipofuscin). Autophagy is a major system of degradation of damaged or unnecessary proteins. However, degenerative RPE cells in AMD patients cannot perform autophagy sufficiently to resist oxidative damage. Increasing evidence supports the idea that enhancing the autophagic process can properly alleviate oxidative injury in AMD and protect RPE and photoreceptor cells from degeneration and death, although overactivated autophagy may lead to cell death at early stages of retinal degenerative diseases. The crosstalk among the NFE2L2, PGC-1, p62, AMPK, and PI3K/Akt/mTOR pathways may play a crucial role in improving disturbed autophagy and mitigating the progression of AMD. In this review, we discuss how autophagy prevents oxidative damage in AMD, summarize potential neuroprotective strategies for therapeutic interventions, and provide an overview of these neuroprotective mechanisms.

Endoplasmic reticulum stress and the protein degradation system in ophthalmic diseases.

OBJECTIVE: Endoplasmic reticulum (ER) stress is involved in the pathogenesis of various ophthalmic diseases, and ER stress-mediated degradation systems play an important role in maintaining ER homeostasis during ER stress. The purpose of this review is to explore the potential relationship between them and to find their equilibrium sites. DESIGN: This review illustrates the important role of reasonable regulation of the protein degradation system in ER stress-mediated ophthalmic diseases. There were 128 articles chosen for review in this study, and the keywords used for article research are ER stress, autophagy, UPS, ophthalmic disease, and ocular. DATA SOURCES: The data are from Web of Science, PubMed, with no language restrictions from inception until 2019 Jul. RESULTS: The ubiquitin proteasome system (UPS) and autophagy are important degradation systems in ER stress. They can restore ER homeostasis, but if ER stress cannot be relieved in time, cell death may occur. However, they are not independent of each other, and the relationship between them is complementary. Therefore, we propose that ER stability can be achieved by adjusting the balance between them. CONCLUSION: The degradation system of ER stress, UPS and autophagy are interrelated. Because an imbalance between the UPS and autophagy can cause cell death, regulating that balance may suppress ER stress and protect cells against pathological stress damage.

Neuroprotection by Therapeutic Hypothermia.

Hypothermia therapy is an old and important method of neuroprotection. Until now, many neurological diseases such as stroke, traumatic brain injury, intracranial pressure elevation, subarachnoid hemorrhage, spinal cord injury, hepatic encephalopathy, and neonatal peripartum encephalopathy have proven to be suppressed by therapeutic hypothermia. Beneficial effects of therapeutic hypothermia have also been discovered, and progress has been made toward improving the benefits of therapeutic hypothermia further through combination with other neuroprotective treatments and by probing the mechanism of hypothermia neuroprotection. In this review, we compare different hypothermia induction methods and provide a summarized account of the synergistic effect of hypothermia therapy with other neuroprotective treatments, along with an overview of hypothermia neuroprotection mechanisms and cold/hypothermia-induced proteins.