Juglone as a Natural Quorum Sensing Inhibitor against Pseudomonas aeruginosa pqs-Mediated Virulence and Biofilms.

Pseudomonas aeruginosa is a notorious opportunistic pathogen associated with chronic biofilm-related infections, posing a significant challenge to effective treatment strategies. Quorum sensing (QS) and biofilm formation are critical virulence factors employed by P. aeruginosa, contributing to its pathogenicity and antibiotic resistance. Other than the homoserine-based QS systems, P. aeruginosa also possesses the quinolone-based Pseudomonas quinolone signal (PQS) QS signaling. Synthesis of the PQS signaling molecule is achieved by the pqsABCDEH operon, whereas the PQS signaling response was mediated by the PqsR receptor. In this study, we report the discovery of a novel natural compound, Juglone, with potent inhibitory effects on pqs QS and biofilm formation in P. aeruginosa. Through an extensive screening of natural compounds from diverse sources, we identified Juglone, a natural compound from walnut, as a promising candidate. We showed that Juglone could inhibit PqsR and the molecular docking results revealed that Juglone could potentially bind to the PqsR active site. Furthermore, Juglone could inhibit pqs-regulated virulence factors, such as pyocyanin and the PQS QS signaling molecule. Juglone could also significantly reduce both the quantity and quality of P. aeruginosa biofilms. Notably, this compound exhibited minimal cytotoxicity toward mammalian cells, suggesting its potential safety for therapeutic applications. To explore the clinical relevance of Juglone, we investigated its combinatorial effects with colistin, a commonly used antibiotic against P. aeruginosa infections. The Juglone-colistin combinatorial treatment could eliminate biofilms formed by wild-type P. aeruginosa PAO1 and its clinical isolates collected from cystic fibrosis patients. The Juglone-colistin combinatorial therapy dramatically improved colistin efficacy and reduced inflammation in a wound infection model, indicating its potential for clinical utility. In conclusion, the discovery of Juglone provides insights into the development of innovative antivirulence therapeutic strategies to combat P. aeruginosa biofilm-associated infections.

Bacterivorous nematodes decipher microbial iron siderophores as prey cue in predator-prey interactions.

The minimal levels of biological-available iron in the environment impose growth limitation on all living organisms. Microbes often secrete high iron-binding-affinity siderophores at high concentrations for scavenging iron from the iron-limited habitats. However, the high prevalence of siderophores released by bacteria into the environment raises an intriguing question whether this chemical cue can be detected by bacterivorous predators. Here, we show that the bacterivorous Caenorhabditis elegans nematode could employ its chemosensory receptor Odr-10 to detect pyoverdine, an iron siderophore secreted by an environmental bacterium, Pseudomonas aeruginosa. This enabled the nematode predator to migrate toward the prey. Our soil microcosm study showed that the detection of pyoverdine and subsequent feeding of P. aeruginosa prey by C. elegans could lead to the expansion of its population. These results showed that siderophores are a prey chemical cue by predators, with key implications in predator-prey interactions.

Distinct bacterial population dynamics and disease dissemination after biofilm dispersal and disassembly.

Microbial communities that form surface-attached biofilms must release and disperse their constituent cells into the environment to colonize fresh sites for continued survival of their species. For pathogens, biofilm dispersal is crucial for microbial transmission from environmental reservoirs to hosts, cross-host transmission, and dissemination of infections across tissues within the host. However, research on biofilm dispersal and its consequences in colonization of fresh sites remain poorly understood. Bacterial cells can depart from biofilms via stimuli-induced dispersal or disassembly due to direct degradation of the biofilm matrix, but the complex heterogeneity of bacterial populations released from biofilms rendered their study difficult. Using a novel 3D-bacterial "biofilm-dispersal-then-recolonization" (BDR) microfluidic model, we demonstrated that Pseudomonas aeruginosa biofilms undergo distinct spatiotemporal dynamics during chemical-induced dispersal (CID) and enzymatic disassembly (EDA), with contrasting consequences in recolonization and disease dissemination. Active CID required bacteria to employ bdlA dispersal gene and flagella to depart from biofilms as single cells at consistent velocities but could not recolonize fresh surfaces. This prevented the disseminated bacteria cells from infecting lung spheroids and Caenorhabditis elegans in on-chip coculture experiments. In contrast, EDA by degradation of a major biofilm exopolysaccharide (Psl) released immotile aggregates at high initial velocities, enabling the bacteria to recolonize fresh surfaces and cause infections in the hosts efficiently. Hence, biofilm dispersal is more complex than previously thought, where bacterial populations adopting distinct behavior after biofilm departure may be the key to survival of bacterial species and dissemination of diseases.

Biofilm dispersal induced by mechanical cutting leads to heightened foodborne pathogen dissemination.

The biofilm life cycle where bacteria alternate between biofilm and planktonic lifestyles poses major implications in food spoilage and gastrointestinal infections. Recent studies had shown that freshly biofilm-dispersed cells have a unique physiology from planktonic cells, raising the fundamental question if biofilm-dispersed cells and planktonic cells disseminate differently across food surfaces. Mechanical dislodging via cutting can cause biofilm dispersal and eventual food cross-contamination. Here, we showed that biofilm-dispersed bacteria from various foodborne pathogens were transferred from freshly cut surface at a higher rate to the cutting material than that of planktonic bacteria. When the cutting tool was used to cut a fresh surface, more biofilm-dispersed bacteria were disseminated from the cutting tool to the newly cut surface than planktonic bacteria. Our observations were applicable to cutting tools of various materials and cut surfaces, where polystyrene and surfaces with high water content were most susceptible to biofilm transfer, respectively. Simple washing with detergent and mechanical wiping could aid bacterial removal from cutting tools. Our work revealed that biofilm-dispersed cells were transferred at a higher rate than planktonic cells and cutting tool was an important medium for pathogen cross-contamination, thus providing insights in maintaining their cleanliness in food processing industries.

Angiotensin II type 1 receptor blockers favorably affect renal angiotensin II and MAS receptor expression in patients with diabetic nephropathy.

INTRODUCTION: The aims of this study were to assess the renal expression of angiotensin II type 1 receptor (AT1R), angiotensin II type 2 receptor (AT2R), and MAS receptor in human type 2 diabetic nephropathy (DN). MATERIALS AND METHODS: In total, 115 patients diagnosed with DN by renal biopsy were enrolled in this study. The protein expression levels of the AT1R, AT2R, and MAS receptors were assessed by immunohistochemistry. RESULTS: The protein expression levels of AT1R, AT2R, and MAS receptor in the renal biopsy tissue were correlated with the pathologic classification of DN. Tubulointerstitial AT1R expression in patients of class IIb was significantly stronger than control samples (p < 0.05). Expression of AT2R and MAS receptors were highest with class IIb DN patients. When DN patients were treated with AT1R blocker (ARB), the expression of AT1R was downregulated (p < 0.05), and the MAS receptor was upregulated in tubular interstitial (p < 0.05). CONCLUSIONS: Our results directly observed that renal expression levels of AT1R increase during the early stages of DN, ARB reducing AT1R while increasing MAS receptor. Therefore, ARB should be used as soon as possible in patients with DN.

Expression of the intrarenal angiotensin receptor and the role of renin-angiotensin system inhibitors in IgA nephropathy.

The critical role of the intrarenal renin-angiotensin system (RAS) in the development of kidney disease has been well demonstrated in animal and cell-culture experiments, but evidence from human kidney tissues is lacking. In this study, we screened 438 patients with IgA nephropathy (IgAN) and analyzed their clinical characteristics. Renal biopsy revealed the expression of angiotensin II type 1 receptor (AT1R), angiotensin II type 2 receptor (AT2R), and MAS receptor (MASR) in the tissues of 260 patients not treated with RAS inhibitors, 32 patients treated with angiotensin-converting enzyme inhibitors (ACEIs), and 89 patients treated with angiotensin receptor blockers (ARBs). The correlations in expression among these three receptors and the results of Oxford typing were analyzed, together with the ability of ACEIs and ARBs to reduce proteinuria and the effects of ARBs on AT1R and AT2R expression. The results showed significantly higher AT1R, AT2R, and MASR expression in the M1 group (mesangial score > 0.5) than in the M0 group (mesangial score < 0.5), significantly higher AT1R expression in the S1 group (presence of segmental glomerulosclerosis) than in the S0 group (absence of segmental glomerulosclerosis); AT1R expression in the C2 group (crescent formation > 25%) was significantly higher than in the C0 (crescent formation = 0) and C1 (crescent formation < 25%) groups. Patients treated with an ARB for < 6 months had significantly lower urinary protein levels than those taking these drugs for > 6 months. These findings imply that overexpression of AT1R on the mesangial cells of IgAN patients is associated with mesangial cell proliferation, glomerular segmental sclerosis, and crescent formation. In addition, long-term administration of ARB may decrease the efficacy of these medications in terms of reducing proteinuria.

1,25-Dihydroxyvitamin D3 inhibits the proliferation of rat mesangial cells induced by high glucose via DDIT4.

1,25-Dihydroxyvitamin D3(1,25(OH)2 D3) is a secosteroid with antiproliferative property. It also plays a pivotal renoprotective role in diabetic nephropathy. We investigated whether 1,25(OH)2D3 could inhibit the proliferation of rat mesangial cells exposed to high glucose via the DNA-damage-inducible transcript 4/mammalian target of rapamycin(DDIT4/mTOR) pathway. The cell proliferation rate and cell cycle duration were measured using cell counting kit-8 assay and flow cytometry. Protein expression was assayed by Western blot. Glucose acted as a growth factor in rat mesangial cells, promoted cell proliferation. In parallel, the protein expression of DDIT4, TSC1/TSC2, and 4E-BP1 were decreased, and Rheb, mTOR, and p70S6K were increased. Acting via the DDIT4/mTOR signaling, 1,25(OH)2 D3 treatment reversed these pathological changes, upregulated DDIT4, TSC1/TSC2, and 4E-BP1, downregulated Rheb, mTOR, and p70S6K. The short-term overexpression of DDIT4 inhibited the proliferation of rat mesangial cells, similar to 1,25(OH)2 D3 treatment. siRNA knockdown of DDIT4 suppressed antiproliferative responses to 1,25(OH)2 D3. These results suggest that 1,25(OH)2 D3 inhibits the proliferation of rat mesangial cells induced by high glucose via the DDIT4/mTOR signaling pathway.

Effects of adding Rheum officinale to angiotensin-converting enzyme inhibitors or angiotensin receptor blockers on renal function in patients with chronic renal failure: A meta-analysis of randomized controlled trials
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OBJECTIVE: Rheum officinale is a traditional medicinal herb used widely in China to treat chronic renal failure, but the proof of evidence-based medicine is poor. This meta-analysis aims to assess the benefits of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) supplemented with Rheum officinale for delaying the progression of chronic renal failure. MATERIALS AND METHODS: The MEDLINE, EMBASE, Cochrane Library, SinoMed, Chinese National Knowledge Infrastructure, Wanfang, and VIP databases were searched to identify studies published before September 2016 that investigated the effects of ACEI/ARB plus the Chinese patented medicine Rheum (CPM-Rheum) compared to ACEI/ARB alone in lowering serum creatinine (SCr) and blood urea nitrogen (BUN) levels in chronic renal failure patients. Review Manager 5.3 was used to perform the meta-analysis. Fixed- and random-effects models were used to analyze the data. RESULTS: The meta-analysis included nine clinical trials. Comparisons of patients before and after treatment with ACEI/ARB plus CPM-Rheum or ACEI/ARB alone revealed that ACEI/ARB plus CPM-Rheum resulted in significantly greater reductions in SCr (short-term: weighted mean difference (WMD): 17.26, 95% confidence interval (CI): 7.28 - 27.24; long-term: WMD: 63.71, 95% CI: 51.01 - 76.41) and BUN (short-term: WMD: 1.70, 95% CI: 1.27 - 2.12; long-term: WMD: 3.98, 95% CI: 3.14 - 4.82) than ACEI/ARB alone. CONCLUSION: In patients with chronic renal failure, the addition of CPM-Rheum to ACEI/ARB significantly lowered both SCr and BUN, particularly after long-term administration. Thus, the combination of ACEI/ARB and CPM-Rheum may improve the treatment of patients with impaired renal function.
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A Meta-Analysis of Antiviral Therapy for Hepatitis B Virus-Associated Membranous Nephropathy.

Hepatitis B virus-associated membranous nephropathy (HBV-MN) is the most common renal extra-hepatic manifestation in patients with chronic HBV infection. In September 2015, we searched the MEDLINE, EMBASE, and CENTRAL databases, and the reference lists of retrieved articles, to identify relevant studies. Descriptions of antiviral drugs used to treat HBV-MN were included in our review. Two authors independently screened all relevant articles, extracted data, and assessed the risk of bias. Nine hundred and fifty-four papers have been considered after electronic and manual searching, only five relevant studies were identified. Complete remission (OR = 26.87, 95% CI: 8.06 to 89.52), total remission (OR = 10.31, 95% CI: 3.59 to 29.63) of proteinuria and HBeAg clearance (OR = 20.91, 95% CI: 6.90 to 63.39) increased significantly after antiviral therapy. No significant differences were seen between interferon and nucleoside analog treatments. Our study found that antiviral therapy was an effective treatment in HBV-MN patients; interferon and nucleoside analogs were equally effective at causing proteinuria remission and HBeAg clearance.

Occurrence and risk assessment of pharmaceuticals and personal care products and endocrine disrupting chemicals in reclaimed water and receiving groundwater in China.

Groundwater recharge using reclaimed water is considered a promising method to alleviate groundwater depletion. However, pollutants in reclaimed water could be recharged into groundwater during this process, thereby posing a risk to groundwater and human health. In this study, 12 cities in northern China were selected for reclaimed water and groundwater sampling. Analysis of the samples revealed the presence of nine pharmaceutical and personal care products (PPCPs) and five endocrine disrupting compounds (EDCs). In reclaimed water, all the PPCPs and EDCs were found, with sulpiride (SP) and estriol (E3) being most frequently detected. In groundwater samples, only ketoprofen (KP), mefenamic acid (MA), nalidixic acid (NA) and SP were detected among PPCPs, while bisphenol-A (BPA) was dominant among the target EDCs. The risk quotients (RQs) of all target PPCPs and EDCs except 17α-ethinyl estradiol (EE2) and E3 were below 1 in groundwater samples, indicating that EE2 and E3 deserve priority preferential treatment before recharging.

Occurrences and regional distributions of 20 antibiotics in water bodies during groundwater recharge.

To develop a better understanding of the pollution conditions of antibiotics during the groundwater recharge process, a nation-wide survey was conducted across China for the first time. Overall, 15 recharge sites employing reclaimed water located in different humid, semi-humid and semi-arid regions were selected for analysis of the presence of the 20 most commonly used antibiotics, including tetracyclines (TCs), fluoroquinolones (FQNs), sulfonamides (SAs) and macrolides. All types of antibiotics were detected at concentrations of 212-4035 ng/L in reclaimed water and 19-1270 ng/L in groundwater. FQNs were the predominant antibiotics in reclaimed water samples (38%), followed by SAs (34%). In the SAs group, sulfamethoxazole (SMZ) and sulfamonomethoxine together with trimethoprim accounted for 78% of the total, while ofloxacin (OFL) and norfloxacin accounted for 90% of the FQNs, and doxycycline and oxytetracycline accounted for 82% of the TCs. The concentrations in groundwater were generally 1-2 orders of magnitude lower than in reclaimed water. The three most common antibiotics were OFL, erythromycin (ERY) and SMZ. Similar occurrences of different group antibiotics might be evidence of the influence of groundwater recharge by reclaimed water. FQNs were predominant in northern China, while SAs were predominant in the south. Ecotoxicological risk assessment showed that SMZ, ERY and OFL had the top three hazard quotient values, indicating they should receive preferential treatment before recharging. Overall, these results provide a theoretical basis for development of a recharge standard in China.

Identification of priority organic compounds in groundwater recharge of China.

Groundwater recharge using reclaimed water is considered a promising method to alleviate groundwater depletion, especially in arid areas. Traditional water treatment systems are inefficient to remove all the types of contaminants that would pose risks to groundwater, so it is crucial to establish a priority list of organic compounds (OCs) that deserve the preferential treatment. In this study, a comprehensive ranking system was developed to determine the list and then applied to China. 151 OCs, for which occurrence data in the wastewater treatment plants were available, were selected as candidate OCs. Based on their occurrence, exposure potential and ecological effects, two different rankings of OCs were established respectively for groundwater recharge by surface infiltration and direct aquifer injection. Thirty-four OCs were regarded as having no risks while the remaining 117 OCs were divided into three groups: high, moderate and low priority OCs. Regardless of the recharge way, nonylphenol, erythromycin and ibuprofen were the highest priority OCs; their removal should be prioritized. Also the database should be updated as detecting technology is developed.

Spatial and seasonal variations of occurrences and concentrations of endocrine disrupting chemicals in unconfined and confined aquifers recharged by reclaimed water: a field study along the Chaobai River, Beijing.

A field study on the spatial and seasonal variations of occurrences and concentrations of five selected endocrine disrupting chemicals (EDCs), namely, estrone, 17ß-estradiol, 17α-ethinyl estradiol, estriol, and bisphenol A, was conducted in Beijing, where reclaimed water is used to recharge groundwater through the permeable bed of the Chaobai River. This study collected 64 surface water samples from the Wenyu and the Chaobai Rivers and 51 groundwater samples from the unconfined aquifer (UA) and two underlying confined aquifers (CA I and CA II) at depths of 30, 50 and 80 m, respectively. EDCs were detected in 100.0%, 94.4% and 40.0% of groundwater samples from the UA, CA I and CA II, respectively, at concentrations which decreased by 1-2 orders of magnitude with depth. The occurrences and concentrations of EDCs in groundwater also decreased with the increasing distance to the river bank. In one monitoring section with seasonal wetting and drying, the occurrences and concentrations of EDCs dropped significantly during the dry season (December to March) without recharging. These results indicate that improving the removal of EDCs in reclaimed water and optimizing the management of the recharging operation could reduce the risks of endocrine disrupting chemicals.