Browsing by Author "Zhang, Hongji"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    IL-18 Activation is Dependent on Toll Like Receptor 4 during Renal Obstruction
    (Elsevier, 2013) Rhee, Audrey C.; Cain, Alexandra L.; Hile, Karen L.; Zhang, Hongji; Matsui, Futoshi; Meldrum, Kirstan K.; Urology, School of Medicine
    Purpose: Interleukin 18 (IL-18) is a critical mediator of obstruction-induced renal injury. Although previous studies have demonstrated that IL-18 participates in a positive feedback loop via the IL-18 receptor (IL-18R) and localized renal IL-18 and IL-18R production to tubular epithelial cells (TEC), the mechanism of IL-18 activation during obstruction remains unclear. We hypothesized that IL-18 activation is dependent on Toll-like receptor 4 (TLR4) signaling during renal obstruction. Materials and methods: Male C57BL6 TLR4 knockout (TLR4KO) and wild-type (WT) mice were subjected to unilateral ureteral obstruction versus sham operation for 1 wk. The animals were sacrificed, and renal cortical tissue was harvested and analyzed for TLR4 expression (Western blot), active IL-18 production (enzyme-linked immunosorbent assay, real-time polymerase chain reaction), IL-18 receptor expression (real-time polymerase chain reaction), and TLR4/IL-18 versus IL-18R cellular localization (dual immunofluorescent staining). Results: Renal TLR4 expression increased significantly in WT mice in response to obstruction, but remained at sham treatment levels in TLR4KO mice. IL-18 and IL-18R gene expression and active IL-18 production were similarly increased in WT mice in response to obstruction, but decreased significantly to sham treatment levels in the absence of TLR4. Dual immunofluorescent staining revealed co-localization of TLR4 and IL-18 to renal TEC during obstruction. Conclusion: IL-18 production and activation during renal obstruction is dependent on intact TLR4 signaling. Co-localization of IL-18 and TLR4 production to TEC during obstruction suggests that TEC are the primary site of IL-18 production and activation. Further characterization of the pathway may be necessary to develop targeted therapy in obstruction-induced renal injury.
  • Thumbnail Image
    Item
    Mesenchymal stem cells protect against obstruction-induced renal fibrosis by decreasing STAT3 activation and STAT3-dependent MMP-9 production
    (American Physiological Society, 2017-01-01) Matsui, Futoshi; Babitz, Stephen A.; Rhee, Audrey; Hile, Karen L.; Zhang, Hongji; Meldrum, Kirstan K.; Urology, School of Medicine
    STAT3 is a transcription factor implicated in renal fibrotic injury, but the role of STAT3 in mesenchymal stem cell (MSC)-induced renoprotection during renal fibrosis remains unknown. We hypothesized that MSCs protect against obstruction-induced renal fibrosis by downregulating STAT3 activation and STAT3-induced matrix metalloproteinase-9 (MMP-9) expression. Male Sprague-Dawley rats underwent renal arterial injection of vehicle or MSCs (1 × 106/rat) immediately before sham operation or induction of unilateral ureteral obstruction (UUO). The kidneys were harvested after 4 wk and analyzed for collagen I and III gene expression, collagen deposition (Masson's trichrome), fibronectin, α-smooth muscle actin, active STAT3 (p-STAT3), MMP-9, and tissue inhibitor of matrix metalloproteinases 1 (TIMP-1) expression. In a separate arm, the STAT3 inhibitor S3I-201 (10 mg/kg) vs. vehicle was administered to rats intraperitoneally just after induction of UUO and daily for 14 days thereafter. The kidneys were harvested after 2 wk and analyzed for p-STAT3 and MMP-9 expression, and collagen and fibronectin deposition. Renal obstruction induced a significant increase in collagen, fibronectin, α-SMA, p-STAT3, MMP-9, and TIMP-1 expression while exogenously administered MSCs significantly reduced these indicators of obstruction-induced renal fibrosis. STAT3 inhibition with S3I-201 significantly reduced obstruction-induced MMP-9 expression and tubulointerstitial fibrosis. These results demonstrate that MSCs protect against obstruction-induced renal fibrosis, in part, by decreasing STAT3 activation and STAT3-dependent MMP-9 production.
  • Thumbnail Image
    Item
    Renal IL-18 Production Is Macrophage Independent During Obstructive Injury
    (Public Library of Science, 2012) Franke, Ethan I.; Vanderbrink, Brian A.; Hile, Karen L.; Zhang, Hongji; Cain, Alexandra; Matsui, Futoshi; Meldrum, Kirstan K.; Urology, School of Medicine
    Background: Interleukin 18 (IL-18) is a pro-inflammatory cytokine that mediates fibrotic renal injury during obstruction. Macrophages are a well-known source of IL-18; however, renal tubular epithelial cells are also a potential source of this cytokine. We hypothesized that IL-18 is predominantly a renal tubular cell product and is produced during renal obstruction independent of macrophage infiltration. Methods: To study this, male C57BL6 mice were subjected to unilateral ureteral obstruction (UUO) vs. sham operation in the presence or absence of macrophage depletion (liposomal clodronate (1 ml/100 g body weight i.v.)). The animals were sacrificed 1 week after surgery and renal cortical tissue harvested. Tissue levels of active IL-18 (ELISA), IL-18 receptor mRNA expression (real time PCR), and active caspase-1 expression (western blot) were measured. The cellular localization of IL-18 and IL-18R was assessed using dual labeling immunofluorescent staining (IFS). Results: Immunohistochemical staining of renal tissue sections confirmed macrophage depletion by liposomal clodronate. IL-18 production, IL-18R expression, and active caspase 1 expression were elevated in response to renal obstruction and did not decline to a significant degree in the presence of macrophage depletion. Obstruction-induced IL-18 and IL-18R production localized predominantly to tubular epithelial cells (TEC) during obstruction despite macrophage depletion. Conclusion: These results demonstrate that renal tubular epithelial cells are the primary source of IL-18 production during obstructive injury, and that tubular cell production of IL-18 occurs independent of macrophage infiltration.
  • Thumbnail Image
    Item
    Stem cell-derived tissue-engineered constructs for hemilaryngeal reconstruction
    (Sage Publications, 2014-02) Halum, Stacey L.; Bijangi-Vishehsaraei, Khadijeh; Zhang, Hongji; Sowinski, John; Bottino, Marco C.; Department of Otolaryngology--Head and Neck Surgery, IU School of Medicine
    OBJECTIVES: As an initial step toward our goal of developing a completely tissue-engineered larynx, the aim of this study was to describe and compare three strategies of creating tissue-engineered muscle-polymer constructs for hemilaryngeal reconstruction. METHODS: Cartilage-mimicking polymer was developed from electrospun poly(D,L-lactide-co-ε-caprolactone) (PCL). Primary muscle progenitor cell cultures were derived from syngeneic F344 rat skeletal muscle biopsies. Twenty F344 rats underwent resection of the outer hemilaryngeal cartilage with the underlying laryngeal adductor muscle. The defects were repaired with muscle stem cell-derived muscle-PCL constructs (5 animals), myotube-derived muscle-PCL constructs (5 animals), motor end plate-expressing muscle-PCL constructs (5 animals), or PCL alone (controls; 5 animals). The outcome measures at 1 month included animal survival, muscle thickness, and innervation status as determined by electromyography and immunohistochemistry. RESULTS: All of the animals survived the 1-month implant period and had appropriate weight gain. The group that received motor end plate-expressing muscle-PCL constructs demonstrated the greatest muscle thickness and the strongest innervation, according to electromyographic activity and the percentage of motor end plates that had nerve contact. CONCLUSIONS: Although all of the tissue-engineered constructs provided effective reconstruction, those that expressed motor end plates before implantation yielded muscle that was more strongly innervated and viable. This finding suggests that this novel approach may be useful in the development of a tissue-engineered laryngeal replacement.
  • Thumbnail Image
    Item
    A two week regimen of high dose integrase inhibitors does not cause nephrotoxicity in mice
    (Sage, 2015-04) Eadon, Michael T.; Zhang, Hongji; Skaar, Todd C.; Hato, Takashi; Dagher, Pierre C.; Gupta, Samir K.; Desta, Zeruesenay; Department of Medicine, IU School of Medicine
    Background The integrase inhibitors, raltegravir and dolutegravir, are nucleoside reverse transcriptase inhibitor-sparing agents which may be used as part of first-line antiretroviral therapy for HIV. These drugs inhibit creatinine secretion through organic cation transporters, thus elevating serum creatinine without affecting glomerular filtration. We sought to determine whether subtle signs of nephrotoxicity could be observed in mice administered a two-week regimen of high-dose integrase inhibitors. Methods C57BL/6 mice were fed standard water (CTRL, n = 6), raltegravir-containing water (40 mg/kg/day, n = 6), or dolutegravir-containing water (2.7 mg/kg/day, n = 6) for two weeks and sacrificed. Endpoints were assessed including urine microalbumin, kidney injury molecule-1 renal tissue gene expression, renal histopathology, serum creatinine, and blood urea nitrogen. Results The results are NOT consistent with a direct nephrotoxic effect of the integrase inhibitors in mice. Serum creatinine was significantly elevated in raltegravir and dolutegravir mice (p < 0.05) compared to control (raltegravir = 0.25 mg/dl, dolutegravir = 0.30 mg/dl versus CTRL = 0.17 mg/dl). Blood urea nitrogen, cystatin C, and urine microalbumin were unchanged. Kidney injury molecule-1 tissue expression in raltegravir and dolutegravir groups was nonsignificantly elevated compared to control (1.2-fold compared to control). Renal histopathology by periodic acid–Schiff staining failed to reveal glomerular or tubular renal injury in any group. Conclusion These studies are consistent with integrase inhibitors competitively inhibiting creatinine secretion. While no evidence of direct nephrotoxicity was observed after two weeks of high-dose drug administration, additional studies may be performed to understand whether these drugs lead to chronic nephropathy.
  • Thumbnail Image
    Item
    Use of autologous adipose-derived mesenchymal stem cells for creation of laryngeal cartilage
    (Wiley, 2018-04) Zhang, Hongji; Voytik-Harbin, Sherry; Brookes, Sarah; Zhang, Lujuan; Wallace, Joseph; Parker, Noah; Halum, Stacey; Biomedical Engineering, School of Engineering and Technology
    OBJECTIVES/HYPOTHESIS: Adipose-derived mesenchymal stem cells (ASCs) are an exciting potential cell source for tissue engineering because cells can be derived from the simple excision of autologous fat. This study introduces a novel approach for tissue-engineering cartilage from ASCs and a customized collagen oligomer solution, and demonstrates that the resultant cartilage can be used for laryngeal cartilage reconstruction in an animal model. STUDY DESIGN: Basic science experimental design. METHODS: ASCs were isolated from F344 rats, seeded in a customized collagen matrix, and cultured in chondrogenic differentiation medium for 1, 2, and 4 weeks until demonstrating cartilage-like characteristics in vitro. Large laryngeal cartilage defects were created in the F344 rat model, with the engineered cartilage used to replace the cartilage defects, and the rats followed for 1 to 3 months. Staining examined cellular morphology and cartilage-specific features. RESULTS: In vitro histological staining revealed rounded chondrocyte-appearing cells evenly residing throughout the customized collagen scaffold, with positive staining for cartilage-specific markers. The cartilage was used to successfully repair large cartilaginous defects in the rat model, with excellent functional results. CONCLUSIONS: This study is the first study to demonstrate, in an animal model, that ASCs cultured in a unique form of collagen oligomer can create functional cartilage-like grafts that can be successfully used for partial laryngeal cartilage replacement.