Riboflavin-loaded carbon cloth aids the anaerobic digestion of cow dung by promoting direct interspecies electron transfer.

Cow dung generates globally due to increased beef and milk consumption, but its treatment efficiency remains low. Previous studies have shown that riboflavin-loaded conductive materials can improve anaerobic digestion through enhance direct interspecies electron transfer (DIET). However, its effect on the practical anaerobic digestion of cow dung remained unclear. In this study, carbon cloth loaded with riboflavin (carbon cloth-riboflavin) was added into an anaerobic digester treating cow dung. The carbon cloth-riboflavin reactor showed a better performance than other two reactors. The metagenomic analysis revealed that Methanothrix on the surface of the carbon cloth predominantly utilized the CO2 reduction for methane production, further enhanced after riboflavin addition, while Methanothrix in bulk sludge were using the acetate decarboxylation pathway. Furthermore, the carbon cloth-riboflavin enriched various major methanogenic pathways and activated a large number of enzymes associated with DIET. Riboflavin's presence altered the microbial communities and the abundance of functional genes relate to DIET, ultimately leading to a better performance of anaerobic digestion for cow dung.

STAT6 promoting oxalate crystal deposition-induced renal fibrosis by mediating macrophage-to-myofibroblast transition via inhibiting fatty acid oxidation.

OBJECTIVE AND DESIGN: Kidney stones commonly occur with a 50% recurrence rate within 5 years, and can elevate the risk of chronic kidney disease. Macrophage-to-myofibroblast transition (MMT) is a newly discovered mechanism that leads to progressive fibrosis in different forms of kidney disease. In this study, we aimed to investigate the role of MMT in renal fibrosis in glyoxylate-induced kidney stone mice and the mechanism by which signal transducer and activator of transcription 6 (STAT6) regulates MMT. METHODS: We collected non-functioning kidneys from patients with stones, established glyoxylate-induced calcium oxalate stone mice model and treated AS1517499 every other day in the treatment group, and constructed a STAT6-knockout RAW264.7 cell line. We first screened the enrichment pathway of the model by transcriptome sequencing; detected renal injury and fibrosis by hematoxylin eosin staining, Von Kossa staining and Sirius red staining; detected MMT levels by multiplexed immunofluorescence and flow cytometry; and verified the binding site of STAT6 at the PPARα promoter by chromatin immunoprecipitation. Fatty acid oxidation (FAO) and fibrosis-related genes were detected by western blot and real-time quantitative polymerase chain reaction. RESULTS: In this study, we found that FAO was downregulated, macrophages converted to myofibroblasts, and STAT6 expression was elevated in stone patients and glyoxylate-induced kidney stone mice. The promotion of FAO in macrophages attenuated MMT and upregulated fibrosis-related genes induced by calcium oxalate treatment. Further, inhibition of peroxisome proliferator-activated receptor-α (PPARα) eliminated the effect of STAT6 deletion on FAO and fibrosis-associated protein expression. Pharmacological inhibition of STAT6 also prevented the development of renal injury, lipid accumulation, MMT, and renal fibrosis. Mechanistically, STAT6 transcriptionally represses PPARα and FAO through cis-inducible elements located in the promoter region of the gene, thereby promoting MMT and renal fibrosis. CONCLUSIONS: These findings establish a role for STAT6 in kidney stone injury-induced renal fibrosis, and suggest that STAT6 may be a therapeutic target for progressive renal fibrosis in patients with nephrolithiasis.

microRNA-486-5p is implicated in the cisplatin-induced apoptosis and acute inflammation response of renal tubular epithelial cells by targeting HAT1.

The proinflammatory property of cisplatin is potentially destructive and contributes to the pathogenesis of acute kidney injury (AKI). The role and upstream regulatory mechanism of histone acetyltransferase 1 (HAT1) in acute kidney inflammation are still unknown. We performed RNA sequencing to filter differentially expressed microRNAs (miRNAs) in the kidney tissue of mice with AKI induced by cisplatin and ischemia-reperfusion. Here, we found that miR-486-5p was upregulated and that the expression of HAT1 was reduced in AKI mouse models and injured human renal proximal tubular epithelial cell (HK-2) model induced by cisplatin. miR-486-5p is implicated in cisplatin-induced kidney damage in vivo. Bioinformatics analysis predicted a potential binding site between miR-486-5p and HAT1. The Luciferase reporter assay and Western blot confirmed that miR-486-5p directly targeted the 3'-untranslated region of HAT1 mRNA and inhibited its expression in the cytoplasm of HK-2 cells. In the in vitro study, inhibiting miR-486-5p reduced apoptosis, and the expression of proinflammatory mediators was induced by cisplatin in HK-2 cells. Simultaneously, the downregulation of miR-486-5p inhibited the activation of the toll-like receptor 4 (TLR4) and nuclear factor-kappa B (NF-κB). We further found that HAT1 could inhibit apoptosis and the activation of cisplatin on the TLR4/NF-κB pathway and that the upregulation of miR-486-5p reversed this effect. Therefore, the upregulation of miR-486-5p targeting HAT1 promoted the cisplatin-induced apoptosis and acute inflammation response of renal tubular epithelial cells by activating the TLR4/NF-κB pathway, providing a new basis to highlight the potential intervention of regulating the miR-486-5p/HAT1 axis.

Comprehensive role of prostate-specific antigen identified with proteomic analysis in prostate cancer.

Current treatments including androgen deprivation fail to prevent prostate cancer (PrCa) from progressing to castration-resistant PrCa (CRPC). Accumulating evidence highlights the relevance of prostate-specific antigen (PSA) in the development and progression of PrCa. The underlying mechanism whereby PSA functions in PrCa, however, has yet been elucidated. We demonstrated that PSA knockdown attenuated tumorigenesis and metastasis of PrCa C4-2 cells in vitro and in vivo, whereas promoted the apoptosis in vitro. To illuminate the comprehensive role of PSA in PrCa, we performed an isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomic analysis to explore the proteomic change induced by PSA knockdown. Among 121 differentially expressed proteins, 67 proteins were up-regulated, while 54 proteins down-regulated. Bioinformatics analysis was used to explore the mechanism through which PSA exerts influence on PrCa. Protein-protein interaction analysis showed that PSA may mediate POTEF, EPHA3, RAD51C, HPGD and MCM4 to promote the initiation and progression of PrCa. We confirmed that PSA knockdown induced the up-regulation of MCM4 and RAD51C, while it down-regulated POTEF and EPHA3; meanwhile, MCM4 was higher in PrCa para-cancerous tissue than in cancerous tissue, suggesting that PSA may facilitate the tumorigenesis by mediating MCM4. Our findings suggest that PSA plays a comprehensive role in the development and progression of PrCa.

MEMS-on-fiber ultrasonic sensor with two resonant frequencies for partial discharges detection.

A novel fiber optic extrinsic Fabry-Perot interferometric (EFPI) ultrasonic sensor with two resonant frequencies for detecting the partial discharges (PDs) in switchgear is demonstrated. The key sensing element consists of two 5-µm-thickness and beam-supported silicon diaphragms, whose natural frequencies are designed differently to enable the sensor to achieve the resonant responses at two different frequencies, thus obtaining a broadened frequency response. The sensing element is fabricated by employing the microelectromechanical systems (MEMS) technology on a silicon-on-insulator (SOI) wafer. The experimental results show that the sensor possesses two resonant frequencies of 31 kHz and 63 kHz, and obviously, shows a highly sensitive frequency response over a broader range compared with the approach composed of a single sensing diaphragm with only one resonant frequency. The noise-limited minimum detectable ultrasonic pressure (MDUP) reaches 251 µPa/Hz1/2@ 31 kHz and 316 µPa/Hz1/2@ 63 kHz, respectively.

MEMS-on-fiber sensor combining silicon diaphragm and supporting beams for on-line partial discharges monitoring.

Fiber optic extrinsic Fabry-Perot interferometric (EFPI) sensors are ideal candidates for on-line partial discharges (PDs) monitoring due to their inherent advantages, such as immunity to electromagnetic interference (EMI), highly compact sensing probes, and remote signal transmission. However, up to date, the design and fabrication of high-performance sensing diaphragms still remain challenging, and most of the reported diaphragms utilize circular structures with the peripheral sidewalls completely fixed. Herein, a novel EFPI ultrasonic sensor for on-line PDs monitoring is demonstrated. The proposed sensing diaphragm combines a silicon beam-supported diaphragm and a fixed boundary ring with a thickness of 5 µm, which was optimized through the multi-objective genetic algorithm (MOGA) revealing its high design flexibility and manufactured by using the microelectromechanical systems (MEMS) processing technology on a silicon-on-insulator (SOI) wafer. Compared with the circular and beam-supported diaphragm, the developed structure exhibits a higher sensitivity. The testing results show that the developed sensor owns the sensitivity and noise-limited minimum detectable ultrasonic pressure (MDUP) of -10 dB re. 1V/Pa and 63 µPa/sqrt(Hz) at its designed resonant frequency, respectively. Finally, the sensor's ability to detect PDs is validated in a temporary built PDs experimental environment, further proving its great potential to perform the on-line PDs monitoring.

[Novel coronavirus induces testicular injury: Analysis of causes and follow-up monitoring].

The outbreak of coronavirus disease 2019 (COVID-19) caused by 2019 novel coronavirus has become a global public health challenge. In addition to the typical respiratory symptoms, COVID-19 can induce damage to testicular spermatogenesis. This study focuses on the possible causes and follow-up monitoring of testicular injury induced by COVID-19.

[Effect of testicular autophagy on spermatogenic cells in varicocele rats].

OBJECTIVE: To study the effect of different levels of autophagy in the testis on the apoptosis of spermatogenic cells in the rat model of varicocele (VC). METHODS: We randomly divided 54 SD male rats into six groups, blank control (n = 6), rapamycin control (n = 6), chloroquine control (n = 6), VC model control (n = 12), VC + rapamycin (n = 12), and VC + chloroquine (n = 12). We observed the histomorphological changes of the testis and epididymis by HE staining, obtained the scores on spermatogenesis in the testis and epididymis, calculated the apoptosis index (AI) of the testicular spermatogenic cells by TUNEL, and determined the expressions of LC3-Ⅱ, LC3-Ⅰ, p62, Bax and Bcl-2 proteins in the testis tissue by Western blot. RESULTS: There were no significant morphological changes in the testis and epididymis of the rats in the blank control, rapamycin control and chloroquine control groups, or significant differences in the scores on testicular and epididymal spermatogenesis and AI of the testicular spermatogenic cells (P>0.05). The animals in the VC model control group exhibited significant pathological damage in the testicular and epididymal tissues, with remarkably decreased scores on spermatogenesis (P<0.01) and increased AI (P<0.01), which were markedly improved in the VC + rapamycin group and slightly aggravated in the VC + chloroquine group compared with the VC model controls. In comparison with the rats in the blank control group, those in the VC model control group showed significantly up-regulated expressions of the autophagy-related protein LC3 (including the LC3-Ⅱ/LC3-Ⅰ ratio) and the pro-apoptotic protein Bax in testicular tissue (P<0.01) but down-regulated expression of the anti-apoptotic protein Bcl-2 (P<0.01). The expressions of LC3 and Bcl-2 in the testis tissue were significantly higher in the VC + rapamycin (P<0.01) but lower in the VC + chloroquine group (P<0.01), while those of p62 and Bax remarkably lower in the VC + rapamycin (P<0.01) but higher in the VC + chloroquine group than in the VC model controls (P<0.01). CONCLUSIONS: Varicocele induces autophagy in the testis and apoptosis of spermatogenic cells in rats. Up-regulating autophagy can inhibit while blocking autophagy can promote the apoptosis of spermatogenic cells.

Low-Cost, High-Performance Fiber Optic Fabry⁻Perot Sensor for Ultrasonic Wave Detection.

This study describes a novel fiber optic extrinsic Fabry⁻Perot interferometric (EFPI) ultrasonic sensor comprising a low-cost and high-performance silicon diaphragm. A vibrating diaphragm, 5 µm thick, was fabricated by using the Microelectromechanical Systems (MEMS) processing technology on a silicon-on-insulator (SOI) wafer. The Fabry⁻Perot (FP) cavity length was solely determined during the manufacturing process of the diaphragm by defining a specific stepped hole on the handling layer of the SOI wafer, which made the assembly of the sensor easier. In addition, the use of cheap and commercially available components and MEMS processing technology in the development of the sensing system, limited the cost of the sensor. The experimental tests showed that the minimum detectable ultrasonic pressure was 1.5 mPa/sqrt(Hz) ⁻0.625 mPa/sqrt(Hz) between 20 kHz and 40 kHz. As a result, this sensor has the potential to successfully detect weak ultrasonic signals.

Locating Ultrasonic Signals Employing MEMS-On-Fiber Sensors.

Sound sensing finds wide applications in various fields, such as underwater detection, structural health monitoring, and medical diagnosis, to name just a few. Based on our previously developed MEMS-on-fiber sensors, showing the advantages of low cost, small volume, and high performance, a three-dimensional ultrasonic localization system employing four such sensors was established in this work. A time difference of arrival (TDOA) algorithm was utilized to analyze the acquired data and then calculate the accurate position of the ultrasonic signal source. Plenty of practical measurements were performed, and the derived localization deviation in the region of 2 m × 2 m × 1 m was about 2-5 mm. Outside this region, the deviation tended to increase due to the directional sensitivity existing in these sensors. As a result, for a more accurate localization requirement, more sensing probes are needed in order to depict a completely suitable application situation for MEMS technology.

Directional Sensitivity of a MEMS-Based Fiber-Optic Extrinsic Fabry⁻Perot Ultrasonic Sensor for Partial Discharge Detection.

Extrinsic Fabry⁻Perot (FP) interferometric sensors are being intensively applied for partial discharge (PD) detection and localization. Previous research work has mainly focused on novel structures and materials to improve the sensitivity and linear response of these sensors. However, the directional response behavior of an FP ultrasonic sensor is also of particular importance in localizing the PD source, which is rarely considered. Here, the directional sensitivity of a microelectromechanical system (MEMS)-based FP ultrasonic sensor with a 5-μm-thick micromechanical vibrating diaphragm is experimentally investigated. Ultrasonic signals from a discharge source with varying incident angles and linear distances are measured and analyzed. The results show that the sensor has a 5.90 dB amplitude fluctuation over a ±60° incident range and an exciting capability to detect weak PD signals from 3 m away due to its high signal⁻noise ratio. The findings are expected to optimize the configuration of a sensor array and accurately localize the PD source.

A Novel High-Performance Beam-Supported Membrane Structure with Enhanced Design Flexibility for Partial Discharge Detection.

A novel beam-supported membrane (BSM) structure for the fiber optic extrinsic Fabry-Perot interferometer (EFPI) sensors showing an enhanced performance and an improved resistance to the temperature change was proposed for detecting partial discharges (PDs). The fundamental frequency, sensitivity, linear range, and flatness of the BSM structure were investigated by employing the finite element simulations. Compared with the intact membrane (IM) structure commonly used by EFPI sensors, BSM structure provides extra geometrical parameters to define the fundamental frequency when the diameter of the whole membrane and its thickness is determined, resulting in an enhanced design flexibility of the sensor structure. According to the simulation results, it is noted that BSM structure not only shows a much higher sensitivity (increased by almost four times for some cases), and a wider working range of fundamental frequency to choose, but also an improved linear range, making the system development much easier. In addition, BSM structure presents a better flatness than its IM counterpart, providing an increased signal-to-noise ratio (SNR). A further improvement of performance is thought to be possible with a step-forward structural optimization. The BSM structure shows a great potential to design the EFPI sensors, as well as others for detecting the acoustic signals.

MiR-153 is Involved in Testicular Ischemia/Reperfusion Injury by Directly Targeting FOXO3 and Regulating Spermatogonia Pyroptosis.

IRI often occurs after detorsion of testicular torsion, which can contribute to permanent damage to sperm production function due to spermatogonia pyroptosis. Mounting data manifest that miRNAs possess a function in the IRI progression. However, the miR-153 function in testicular IRI remains unclear. We aim to elucidate the regulatory mechanism of miR-153 in regulating spermatogonia pyroptosis in testicular IRI. We developed the mouse testicular torsion/detorsion (T/D) model and the oxygen-glucose deprivation/reperfusion (OGD/R) model to examine the miR-153 function in testicular IRI. The extent of testicular ischemic damage was evaluated through HE staining the testicular tissue. Various experimental methods, including Western blotting, QRT-PCR, MDA, SOD assays, and immunohistochemistry (IHC), were deployed to examine the miR-153 levels and the generation of ROS in the testicular tissues. Furthermore, we determined the FoxO3 levels and pyroptosis-related proteins in GC-1 cells. Cell viability was assessed using the CCK-8 assay. Finally, the connection between miR-153 and FoxO3 was verified by employing dual luciferase reporter gene assays and Ago2-RIP. In the testicular IRI, we noted a significant elevation in the pyroptosis-correlated proteins NLRP3, caspase-1 (CASP1), IL-1ß, and IL-18 levels. Furthermore, we noted a significant upregulation of miR-153 in the IRI testicular tissues and GC-1 cells treated with OGD/R, and the miR-153 upregulation increased cell pyroptosis. Conversely, the miR-153 downregulation and FoxO3 overexpression reduced cell pyroptosis. Subsequently, we validated that FoxO3 is a miR-153 target gene. During the OGD/R process, miR-153 increased cell pyroptosis in GC-1 cells by suppressing the FoxO3 expression. We identified that the regulation of testicular IRI-induced cell pyroptosis is mediated by miR-153 via its targeting of FoxO3.

SMYD2 Promotes Calcium Oxalate-Induced Glycolysis in Renal Tubular Epithelial Cells via PTEN Methylation.

Background/Objectives: Damage to renal tubular cells (RTCs) represents a critical pathological manifestation in calcium oxalate (CaOx) stone disease, but the underlying mechanism remains elusive. Energy metabolism reprogramming is a vital influencer of RTC survival, and SMYD2 is a histone methylation transferase that has been extensively implicated in various metabolic disorders. Hence, this research aimed to identify whether SMYD2 induces the reprogramming of energy metabolism in RTCs exposed to CaOx nephrolithiasis. Methods: Kidney samples were obtained from patients who underwent laparoscopic nephrectomy for non-functioning kidneys caused by nephrolithiasis. The glyoxylate-induced CaOx stone mice model was established and treated with AZ505. The SMYD2-knockout HK-2 cell line was constructed. Histological changes were evaluated by HE, VK, Tunel, Masson stainings. The molecular mechanism was explored through co-immunoprecipitation and western blotting. Results: The results found that SMYD2 upregulation led to energy reprogramming to glycolysis in human kidney tissue samples and in mice with CaOx nephrolithiasis. We also identified the substantial involvement of glycolysis in the induction of apoptosis, inflammation, and epithelial-mesenchymal transition (EMT) in HK-2 cells caused by calcium oxalate monohydrate (COM). In vivo and in vitro results demonstrated that SMYD2 inhibition reduces glycolysis, kidney injury, and fibrosis. Mechanistically, SMYD2 was found to promote metabolic reprogramming of RTCs toward glycolysis by activating the AKT/mTOR pathway via methylated PTEN, which mediates CaOx-induced renal injury and fibrosis. Conclusions: Our findings reveal an epigenetic regulatory role of SMYD2 in metabolic reprogramming in CaOx nephrolithiasis and associated kidney injury, suggesting that targeting SMYD2 and glycolysis may represent a potential therapeutic strategy for CaOx-induced kidney injury and fibrosis.

Riboflavin modified carbon cloth enhances anaerobic digestion treating food waste in a pilot-scale system.

Previous laboratory-scale studies have consistently shown that carbon-based conductive materials can notably improve the anaerobic digestion of food waste, typically employing reactors with regular capacity of 1-20 L. Furthermore, incorporating riboflavin-loaded conductive materials can further address the imbalance between fermentation and methanogenesis in anaerobic systems. However, there have been few reports on pilot-scale investigation. In this study, a 10 m2 of riboflavin modified carbon cloth was incorporated into a pilot-scale (2 m3) food waste anaerobic reactor to improve its treatment efficiency. The study found that the addition of riboflavin-loaded carbon cloth can increase the maximum organic loading rate (OLR) by 40% of the pilot-scale reactor, compared to the system using carbon cloth without riboflavin loading, while ensuring efficient operation of the reaction system, effectively alleviating system acidification, sustaining methanogen activity, and increasing daily methane production by 25%. Analysis of the microbial community structure revealed that riboflavin-loaded carbon cloth enriched the methanogenic archaea in the genera of Methanothrix and Methanobacterium, which are capable of extracellular direct interspecies electron transfer (DIET). And metabolic pathway analysis identified the methane production pathway, highly enriched on the reduction of acetic acid and CO2 at riboflavin-loaded carbon cloth sample. The expression levels of genes related to methane production via DIET pathway were also significantly upregulated. These results can provide important guidance for the practical application of food waste anaerobic digestion engineering.

Overexpression of immunoglobulin G prompts cell proliferation and inhibits cell apoptosis in human urothelial carcinoma.

Only B lymphocytes can express immunoglobulins according to the traditional immunological theories, and the expression of immunoglobulin G (IgG) messenger RNA (mRNA) and protein was found in certain human cancer cells recently. However, the expression pattern of IgG and its possible role in human urothelial carcinoma are still elusive. In this study, we investigated the expression of IgG in two human urothelial carcinoma cell lines, T24 and BIU-87, and in 56 cases of clinical urothelial carcinoma tissues. The mRNA of IgG was positively detected by in situ hybridization and reverse transcription PCR; furthermore, IgG protein was also positively detected by immunohistochemistry and Western blot. Moreover, blockade of tumor-derived IgG by either antihuman IgG antibody or antisense oligonucleotides increased cell apoptosis and inhibited cell growth in bladder cancer cell lines in vitro, and antihuman IgG antibody could suppress the growth of xenotransplant tumor in vivo. In addition, either antihuman IgG antibody or antisense oligonucleotides enhanced the sensitivity to mitomycin C in bladder cancer cell line T24. Furthermore, blockade of IgG in bladder cancer cell T24 resulted in upregulation of cleaved caspase-3 and cleaved poly(ADP-ribose) polymerase. Our results indicated that bladder cancer cells were capable of expressing IgG, and blockade of IgG expression induced cell apoptosis through activation of caspase-dependent pathway. A novel potential targeted therapy for bladder cancer will be possibly developed based on these data.

Biocompatibility and efficacy of prostatic urethral lift in benign prostate hyperplasia: an in vivo and in vitro study.

The study aimed to assess the biocompatibility and efficacy of a prostatic urethral lift (PUL) for benign prostatic hyperplasia (BPH). Human BPH-1 cells were co-cultured with implant anchors and sutures, and cytotoxicity was measured. Scanning electron microscopy (SEM) was used to observe adhesion and growth of cells and to evaluate implant biocompatibility. Fifteen male beagle dogs were randomly assigned to the surgical (n = 9) or sham-operated (n = 6) groups. The surgical group underwent cystotomy, and PUL was used to insert two implants in each lobe of the prostate to compress the enlarged prostate and dilate the urethra; the sham group underwent cystotomy without implant insertion. Compared with the control group, no significant difference in cell viability among the groups with different co-culture times of implant anchors and sutures (P > 0.05) was observed. SEM revealed good adhesion and growth of prostate cells on the implants. Improvements in urine flow rates remained stable at 7, 28, and 180 days after surgery, and the urethral diameter in the prostate region was significantly increased compared with that before surgery. PUL is a biocompatible and effective treatment for BPH, improving the urine flow rate without causing inflammation, tissue damage, or cytotoxic effects. Here, the basis for further PUL application was provided.

AID-induced CXCL12 upregulation enhances castration-resistant prostate cancer cell metastasis by stabilizing ß-catenin expression.

Prostate cancer (PCa) is one of the most common malignant diseases of urinary system and has poor prognosis after progression to castration-resistant prostate cancer (CRPC), and increased cytosine methylation heterogeneity is associated with the more aggressive phenotype of PCa cell line. Activation-induced cytidine deaminase (AID) is a multifunctional enzyme and contributes to antibody diversification. However, the dysregulation of AID participates in the progression of multiple diseases and related with certain oncogenes through demethylation. Nevertheless, the role of AID in PCa remains elusive. We observed a significant upregulation of AID expression in PCa samples, which exhibited a negative correlation with E-cadherin expression. Furthermore, AID expression is remarkably higher in CRPC cells than that in HSPC cells, and AID induced the demethylation of CXCL12, which is required to stabilize the Wnt signaling pathway executor ß-catenin and EMT procedure. Our study suggests that AID drives CRPC metastasis by demethylation and can be a potential therapeutic target for CRPC.

Enhancing anaerobic digestion of food waste with granular activated carbon immobilized with riboflavin.

Previous studies have shown that anaerobic digestion of food waste can be enhanced by addition of conductive materials that stimulate direct interspecies electron transfer (DIET) between bacteria and methanogens. However, at extremely high organic loading rates (OLRs), volatile fatty acids (VFAs) still tend to accumulate even in the presence of conductive materials because of an imbalance between the formation of fermentation products and the rate of methanogenesis. In this study, granular activated carbon (GAC) immobilized with riboflavin (GAC-riboflavin) was added to an anaerobic digester treating food waste. The GAC-riboflavin reactor operated stably at OLRs as high as 11.5 kgCOD/ (m3·d) and kept VFA concentrations below 69.4 mM, COD removal efficiencies, methane production rates, and biogas methane concentrations were much higher in the GAC-riboflavin reactor than the GAC- and non-amended reactors. Transcripts associated with genes that code for proteins involved in DIET based metabolism were somewhat more highly expressed by Methanothrix in the GAC-riboflavin reactor. However, it is unlikely that riboflavin acted as an electron shuttle to stimulate DIET. Rather, it seemed to provide nutrients that enhanced the growth of microorganisms involved in the anaerobic digestion process, including those that are capable of DIET.

CXCR4 inhibition attenuates calcium oxalate crystal deposition-induced renal fibrosis.

Nephrolithiasis is a highly prevalent urological disease and results in a correspondingly heavy socioeconomic and healthcare burden. Calcium oxalate (CaOx) stones are among the most common types of kidney stones. They are associated with renal tubular damage, interstitial fibrosis and chronic kidney disease (CKD). However, the molecular mechanisms in CaOx crystal deposition-induced renal fibrosis remain unclear. Chemokines and their receptors act a crucial role in the progression of renal fibrosis through inflammatory cell infiltration, autophagy activation, and epithelial-mesenchymal transition (EMT). The current work aims to study the action and mechanism of the C-X-C motif chemokine receptor 4 (CXCR4) in CaOx crystal deposition-induced renal fibrosis. Transcriptome RNA sequencing, qPCR, and immunohistochemistry revealed that the expression of CXCR4 was significantly upregulated in patients with nephrolithiasis and hyperoxaluric mice. Renal injury and fibrosis were significantly suppressed by inhibiting CXCR4 with AMD3100 or siRNA in hyperoxaluric mice and oxalate-stimulated HK-2 cells; EMT, reactive oxygen species (ROS) levels, and autophagy were also suppressed. Bioinformatic analysis revealed that the NF-κB pathway was activated in hyperoxaluric mice. Mechanistically, activation of the NF-κB pathway was suppressed by CXCR4 inhibition in CaOx crystal-induced renal fibrosis; this suppression was significantly aggravated by the NF-κB inhibitor BAY-11-7085. Moreover, inhibition of autophagy attenuated EMT progression in vitro. Our results suggest that CXCR4 inhibition attenuates CaOx crystal deposition-induced renal fibrosis by suppressing autophagy and EMT through the NF-κB pathway. Therefore, CXCR4 is a potential target for preventing renal fibrosis in patients with nephrolithiasis.