SERPINA3K prevents oxidative stress induced necrotic cell death by inhibiting calcium overload

Hypothermic machine perfusion reduces donation after circulatory death liver ischemia-reperfusion injury through the SERPINA3-mediated PI3Kδ/Akt pathway

Hypothermic machine perfusion (HMP) has been demonstrated to be more effective in mitigating ischemia-reperfusion injury (IRI) of donation after circulatory death (DCD) organs than cold storage (CS), yet the underlying mechanism remains obscure. We aimed to propose a novel therapeutic approach to ameliorate IRI in DCD liver transplantation. Twelve clinical liver samples were randomly assigned to HMP or CS treatment and subsequent transcriptomics analysis was performed. By combining in vivo HMP models, we discovered that HMP attenuated inflammation, oxidative stress, and apoptosis in DCD liver through a SEPRINA3-mediated PI3Kδ/AKT signaling cascade. Moreover, in the hypoxia/reoxygenation (H/R) model of BRL-3A, overexpression of SERPINA3 mitigated H/R-induced apoptosis, while SERPINA3 knockdown exacerbated cell injury. Idelalisib (IDE) treatment also reversed the protective effect of SERPINA3 overexpression. Overall, our research provided new insights into therapeutic strategies and identified potential novel molecular targets for therapeutic intervention against DCD liver.

Role of Serine Protease Inhibitors A1 and A3 in Ocular Pathologies

Serine protease inhibitors A1 (SerpinA1) and A3 (SerpinA3) are important members of the serpin family, playing crucial roles in the regulation of serine proteases and influencing various physiological processes. SerpinA1, also known as α-1-antitrypsin, is a versatile glycoprotein predominantly synthesized in the liver, with additional production in inflammatory and epithelial cell types. It exhibits multifaceted functions, including immune modulation, complement activation regulation, and inhibition of endothelial cell apoptosis. SerpinA3, also known as α-1-antichymotrypsin, is expressed both extracellularly and intracellularly in various tissues, particularly in the retina, kidney, liver, and pancreas. It exerts anti-inflammatory, anti-angiogenic, antioxidant, and antifibrotic activities. Both SerpinA1 and SerpinA3 have been implicated in conditions such as keratitis, diabetic retinopathy, age-related macular degeneration, glaucoma, cataracts, dry eye disease, keratoconus, uveitis, and pterygium. Their role in influencing metalloproteinases and cytokines, as well as endothelial permeability, and their protective effects on Müller cells against oxidative stress further highlight their diverse and critical roles in ocular pathologies. This review provides a comprehensive overview of the etiology and functions of SerpinA1 and SerpinA3 in ocular diseases, emphasizing their multifaceted roles and the complexity of their interactions within the ocular microenvironment.

SerpinA3K Deficiency Reduces Oxidative Stress in Acute Kidney Injury

We previously showed that SerpinA3K is present in urine from rats and humans with acute kidney injury (AKI) and chronic kidney disease (CKD). However, the specific role of SerpinA3K during renal pathophysiology is unknown. To begin to understand the role of SerpinA3K on AKI, SerpinA3K-deficient (KOSA3) mice were studied 24 h after inducing ischemia/reperfusion (I/R) and compared to wild type (WT) mice. Four groups were studied: WT+S, WT+IR, KOSA3+S, and KOSA3+IR. As expected, I/R increased serum creatinine and BUN, with a GFR reduction in both genotypes; however, renal dysfunction was ameliorated in the KOSA3+IR group. Interestingly, the increase in UH₂O₂ induced by I/R was not equally seen in the KOSA3+IR group, an effect that was associated with the preservation of antioxidant enzymes' mRNA levels. Additionally, FOXO3 expression was initially greater in the KOSA3 than in the WT group. Moreover, the increase in BAX protein level and the decrease in Hif1a and Vegfa induced by I/R were not observed in the KOSA3+IR group, suggesting that these animals have better cellular responses to hypoxic injury. Our findings suggest that SerpinA3K is involved in the renal oxidant response, HIF1α/VEGF pathway, and cell apoptosis.

Urinary serpin-A3 is an early predictor of clinical response to therapy in patients with proliferative lupus nephritis

We have previously reported that urinary excretion of serpin-A3 (uSerpA3) is significantly elevated in patients with active lupus nephritis (LN). Here, we evaluated the course of uSerpA3 during the first year of treatment and its association with response to therapy in patients with proliferative LN. The observational longitudinal study included 60 Mexican adults with proliferative LN followed during the first year after LN flare. uSerpA3 was detected by Western blot analysis at flare and after 3, 6, and 12 mo. The response to therapy was determined 1 yr after the LN flare. We evaluated the correlation between uSerpA3 and histological parameters at LN flare. The temporal association between uSerpA3 and response to therapy was analyzed with linear mixed models. uSerpA3 prognostic performance for response was evaluated with receiver-operating characteristic curves. Among the 60 patients studied, 21 patients (35%) were class III and 39 patients (65%) were class IV. uSerpA3 was higher in class IV than in class III LN (6.98 vs. 2.89 dots per in./mg creatinine, P = 0.01). Furthermore, uSerpA3 correlated with the histological activity index (r = 0.29, P = 0.02). There was a significant association between the temporal course of uSerpA3 and response to therapy. Responders showed a significant drop in uSerpA3 at 6 mo compared with LN flare (P < 0.001), whereas nonresponders persisted with elevated uSerpA3. Moreover, uSerpA3 was significantly lower at flare in responders compared with nonresponders (2.69 vs. 6.98 dots per in./mg creatinine, P < 0.05). Furthermore, uSerpA3 was able to identify nonresponders since 3 mo after LN flare (area under the curve: 0.77). In conclusion, uSerpA3 is an early indicator of kidney inflammation and predictor of the clinical response to therapy in patients with proliferative LN.NEW & NOTEWORTHY LN requires aggressive immunosuppression to improve long-term outcomes. Current indicators of remission take several months to normalize, prolonging treatment regiments in some cases. Serpin-A3 is present in urine of patients with proliferative LN. We evaluated the excretion of serpin-A3 in serial samples of patients with proliferative LN during the first year after flare. We found that uSerpA3 correlates with kidney inflammation and its decline at early points predicts the response to therapy 1 yr after flare.

Transient response of serpinA3 during cellular stress

We demonstrated that serpinA3c/k relocates from the cytoplasm to the apical tubular membrane (ATM) in chronic kidney disease (CKD), suggesting its secretion in luminal space in pathophysiological contexts. Here, we studied serpinA3c/k expression and secretion under different stressful conditions in vitro and in vivo. HEK-293 cells were transfected with a FLAG-tagged serpinA3c/k clone and exposed to H₂ O₂ or starvation. Both stressors induced serpinA3c/k secretion but with a higher molecular weight. Glycanase treatment established that serpinA3c/k is glycosylated. Site-directed mutagenesis for each of the four glycosylation sites was performed. During cellular stress, serpinA3c/k secretion increased with each mutant except in the quadruple mutant. In rats and patients suffering acute kidney injury (AKI), an atypical urinary serpinA3c/k excretion (uSerpinA3c/k) was observed. In rats with AKI, the greater the induced kidney damage, the greater the uSerpinA3 c/k, together with relocation toward ATM. Our findings show that: (1) serpinA3c/k is glycosylated and secreted, (2) serpinA3c/k secretion increases during cellular stress, (3) its appearance in urine reveals a pathophysiological state, and (4) urinary serpinA3 excretion could become a potential biomarker for AKI.

Multi-omics analysis of brain tissue metabolome and proteome reveals the protective effect of gross saponins of Tribulus terrestris L. fruit against ischemic stroke in rat

ETHNOPHARMACOLOGICAL RELEVANCE

Gross Saponins of Tribulus terrestris L. Fruit (GSTTF) has been reported to have a protective effect against ischemic stroke, but the related mechanism is complex and still not fully investigated.

AIM OF THE STUDY

The combination of metabolomics and proteomics approach was applied to reveal the mechanisms of GSTTF in treating ischemic stroke.

MATERIALS AND METHODS

The metabolite and protein changes in brain tissue were analyzed by the LC-MS-based untargeted metabolomics method and tandem mass tags (TMT)-based quantitative proteomics technology. The multivariate statistical analysis and protein-protein interaction (PPI) analysis were conducted to screen out the biomarkers, and their related pathway was further investigated by the joint pathway analysis.

RESULTS

A total of 110 metabolites and 359 differential proteins, which were mainly associated with complement and coagulation cascades, sphingolipid metabolism, glycerophospholipid metabolism, glutathione metabolism, and platelet activation, etc. were screened out from the rat brain tissue. The PPI network exhibited that the protein F2, Fga, Fgb, Fgg, Plg, and C3, which are greatly involved in the complement and coagulation cascades, have a relatively high connectivity degree, indicating their importance in the process of middle cerebral artery occlusion (MCAO). The GSTTF exerted a protective effect against MCAO via modulating multiple proteins on this pathway. Moreover, F2 played a key role during the protective process and worth to be further investigated due to it has been reported as one of the therapeutic targets of ischemic stroke.

CONCLUSION

The present study could improve the understanding of the potential therapeutic mechanism of GSTTF against ischemic stroke.

Pathogenic role of human C-reactive protein in diabetic retinopathy

PURPOSE

Elevated blood levels of C-reactive protein (CRP) are associated with both type 1 and type 2 diabetes and diabetic complications, such as diabetic retinopathy (DR). However, its pathogenic role in DR remains unknown. The present study aims to investigate the potential role of CRP in DR pathogenesis and explore its underlying mechanism.

MATERIALS AND METHODS

Human CRP transgenic (hCRP-Tg) rats were employed for streptozotocin (STZ)-induced diabetic and oxygen-induced retinopathy (OIR) models. The retina function was monitored by electroretinography (ERG) and retinal thickness was measured by optical coherence tomography (OCT). TUNEL and cell death ELISA were performed to measure the apoptosis. Oxidative stress was detected by the measurement of reactive oxygen species (ROS) in cells and 3-Nitrotyrosine staining in tissue sections.

RESULTS

In non-diabetic condition, hCRP-Tg with elevated hCRP levels in the retinas demonstrated declined ERG responses and decreased retinal thickness. In STZ-induced diabetic condition, overexpression of hCRP deteriorated retinal neurodegeneration as shown by ERG and apoptosis assays. hCRP also exacerbated retinal leukostasis and acellular capillary formation induced by diabetes. In the OIR model, overexpression of hCRP exacerbated retinal neovascularization (NV). In retinal cell lines, hCRP treatment induced cell death and over-production of ROS. Furthermore, hCRP-induced overexpression of pro-inflammatory, pro-oxidative, and pro-angiogenic factors was associated with up-regulation of CD32 and the NF-κB signaling in the retinas.

CONCLUSIONS

Elevated hCRP levels play a pathogenic role in DR. Targeting the hCRP-CD32-NF-κB pathway may represent a novel therapeutic strategy for DR.

Clusterin Deficiency Predisposes C57BL/6j Mice to Cationic Bovine Serum Albumin-Induced Glomerular Inflammation

Background

Membranous nephropathy (MN) is a specific entity of glomerulonephritis, and its glomerular inflammation is characterized by the deposition of immune complexes in the glomerular basement membrane and proteinuria. However, the molecular mechanisms underlying the glomerular inflammation of MN are not fully understood. This study was designed to investigate the role of clusterin (CLU) in the development of MN using a mouse model of cationic bovine serum albumin (cBSA)-induced MN.

Methods

Both wild-type C57BL/6j (WT) and CLU-knockout C57BL/6j (CLU-KO) mice were immunized with cBSA. The kidney function was determined by the levels of serum creatinine (SCr), blood urea nitrogen (BUN) and urinary protein. MN and glomerular deposits of CLU, complement C3 and immunoglobulins (Igs) were determined by histological analyses. Serum proteins were analyzed by the enzyme-linked immunosorbent assay, Western blot and liquid chromatography-mass spectrometry.

Results

Here, we showed that after cBSA immunization, SCr and proteinuria were increased in CLU-KO mice but not in WT mice. Similarly, severe glomerular atrophy and mesangial expansion along with C3 deposit were only found in the kidneys of CLU-KO mice but not in WT mice. However, there were no differences of serum IgG and complement 3 levels between CLU-KO and WT mice. In the serum of WT mice, CLU bound to anti-cBSA IgG, complements (eg, C8), proteinase/protease inhibitors and antioxidative proteins to form a complex, and incubation with WT serum reduced the complement-dependent lysis of podocytes in cultures.

Conclusion

Our data suggest that a CLU deficiency induces cBSA-initiated glomerular inflammation of MN in a disease-resistant strain of mice, suggesting an anti-glomerular inflammatory function of CLU in the resistance to MN development. This function may be at least in part due to the formation of CLU-anti-cBSA Igs complex that prevents glomerular inflammation or injury in the disease-resistant mice.

Neuroprotective Effects of Serpina3k in Traumatic Brain Injury

Traumatic brain injury (TBI) is a major cause of disability and mortality worldwide, in part resulting from secondary apoptosis of neurons in peri-contusion areas. Serpina3k, a serine protease inhibitor, has been shown to inhibit apoptosis in injury models. In this study, we investigated the anti-apoptotic function of serpina3k in vivo using a mouse model of TBI, as well as the underlying neuroprotective mechanism in vitro using the SH-SY5Y human neuroblastoma cell line. TBI was induced in adult male C57BL/6 mice using controlled cortical impact. Serpina3k protein was intravenously administered at a concentration of 0.5 mg/kg twice daily for up to 14 days. SH-SY5Y cells were subjected to biaxial stretch injury and then treated with different concentrations of serpina3k. We found that endogenous serpina3k protein levels were elevated in peri-contusion areas of the mouse brain following TBI. Serpina3k-treated mice had fewer apoptotic neurons, lower levels of oxidative stress, and showed greater recovery of neurological deficits relative to vehicle-treated mice. Meanwhile, in the SH-SY5Y cell injury model, serpina3k at an optimal concentration (150 nM) inhibited the generation of intracellular reactive oxygen species, abrogated changes of the mitochondrial membrane potential, and reduced the phospho-extracellular regulated protein kinases (p-ERK)/ERK, phospho-P38 (p-P38)/P38, B cell lymphoma (Bcl)-2-associated X protein/Bcl-2, and cleaved caspase-3/caspase-3 ratios, thereby reducing the apoptosis rate. These results demonstrate that serpina3k exerts a neuroprotective function following TBI and thus has therapeutic potential.

SerpinA3 in the Early Recognition of Acute Kidney Injury to Chronic Kidney Disease (CKD) transition in the rat and its Potentiality in the Recognition of Patients with CKD

Recognizing patients at early phases of chronic kidney disease (CKD) is difficult, and it is even more challenging to predict acute kidney injury (AKI) and its transition to CKD. The gold standard to timely identify renal fibrosis is the kidney biopsy, an invasive procedure not usually performed for this purpose in clinical practice. SerpinA3 was identified by high-resolution-mass-spectrometry in urines from animals with CKD. An early and progressive elevation of urinary SerpinA3 (uSerpinA3) was observed during the AKI to CKD transition together with SerpinA3 relocation from the cytoplasm to the apical tubular membrane in the rat kidney. uSerpinA3/alpha-1-antichymotrypsin was significantly increased in patients with CKD secondary to focal and segmental glomerulosclerosis (FSGS), ANCA associated vasculitis (AAV) and proliferative class III and IV lupus nephritis (LN). uSerpinA3 levels were independently and positively associated with renal fibrosis. In patients with class V LN, uSerpinA3 levels were not different from healthy volunteers. uSerpinA3 was not found in patients with systemic inflammatory diseases without renal dysfunction. Our observations suggest that uSerpinA3 can detect renal fibrosis and inflammation, with a particular potential for the early detection of AKI to CKD transition and for the differentiation among lupus nephritis classes III/IV and V.

Proteomic characterization of early lung response to breast cancer metastasis in mice

INTRODUCTION

The tumor-promoting rearrangement of the lungs facilitates the process of cancer cell survival in a foreign microenvironment and enables their protection against immune defense. The study aimed to define the fingerprint of the early rearrangement of the lungs via the proteomic profiling of the lung tissue in the experimental model of tumor metastasis in a murine 4T1 mammary adenocarcinoma.

MATERIALS AND METHODS

The studies were performed on 7-8-week-old BALB/c female mice. Viable 4T1 cancer cells were orthotopically inoculated into the right mammary fat pad. The experiment was performed in the early phase of the tumor metastasis one and two weeks after cancer cell inoculation. The comparative analysis of protein profiles was carried out with the aid of the two-dimensional difference in gel electrophoresis (2D-DIGE). Proteins, of which expression differed significantly, were identified using nano-liquid chromatography coupled to a high-resolution mass spectrometry (nanoLC/hybrid ion trap- Orbitrap XL Discovery).

RESULTS

Palpable primary tumors were noted in the 2^nd week after cancer cell inoculation. The investigated period preceded the formation of numerous macrometastases in the lungs, however the metastasis-promoting changes were visible very early. Primary tumor-induced inflammation developed in the lungs as early as after the 1^st week and progressed during the 2^nd week, accompanied by increased concentration of 2-OH-E⁺, an oxidative stress marker, and imbalance in nitric oxide metabolites, pointing to endothelium dysfunction. The early proteomic changes in the lungs in the 1^st week after 4T1 cell inoculation resulted in the reorganization of lung tissue structure [actin, cytoplasmic 1 (Actb), tubulin beta chain (Tubb5), lamin-B1 (Lmnb1), serine protease inhibitor A3K (Serpina3k)] and activation of defense mechanisms [selenium-binding protein 1 (Selenbp1), endoplasmin (Hsp90b1), stress 70 protein, mitochondrial (Hspa9), heat shock protein HSP 90-beta (Hsp90ab1)], but also modifications in metabolic pathways [glucose-6-phosphate 1-dehydrogenase X (G6pdx), ATP synthase subunit beta, mitochondrial (Atp5b), L-lactate dehydrogenase B chain (Ldhb)]. Further development of the solid tumor after the 2^nd week following cancer cell inoculation, secretion of prolific tumor-derived factors as well as the presence of the increasing number of circulating cancer cells and extravasation processes further impose reorganization of the lung tissue [Actb, vimentin (Vim), clathrin light chain A (Clta)], altering additional metabolic pathways [annexin A5 (Anxa5), Rho GDP-dissociation inhibitor 2 (Arhgdib), complement 1 Q subcomponent-binding protein, mitochondrial (C1qbp), 14-3-3 protein zeta/delta (Ywhaz), peroxiredoxin-6 (Prdx6), chitinase-like protein 4 (Chi3l4), reticulocalbin-1 (Rcn1), EF-hand domain-containing protein D2 (Efhd2), calumenin (Calu)]. Interestingly, many of differentially expressed proteins were involved in calcium homeostasis (Rcn1, Efhd2, Calu, Actb, Vim, Lmnb1, Clta, Tubb5, Serpina3k, Hsp90b1, Hsp90ab1, Hspa9. G6pdx, Atp5b, Anxa5, Arhgdib, Ywhaz).

CONCLUSION

The analysis enabled revealing the importance of calcium signaling during the early phase of metastasis development, early cytoskeleton and extracellular matrix reorganization, activation of defense mechanisms and metabolic adaptations. It seems that the tissue response is an interplay between pro- and anti-metastatic mechanisms accompanied by inflammation, oxidative stress and dysfunction of the barrier endothelial cells.

Neuroprotective effects of PPARα in retinopathy of type 1 diabetes

Diabetic retinopathy (DR) is a common neurovascular complication of type 1 diabetes. Current therapeutics target neovascularization characteristic of end-stage disease, but are associated with significant adverse effects. Targeting early events of DR such as neurodegeneration may lead to safer and more effective approaches to treatment. Two independent prospective clinical trials unexpectedly identified that the PPARα agonist fenofibrate had unprecedented therapeutic effects in DR, but gave little insight into the physiological and molecular mechanisms of action. The objective of the present study was to evaluate potential neuroprotective effects of PPARα in DR, and subsequently to identify the responsible mechanism of action. Here we reveal that activation of PPARα had a robust protective effect on retinal function as shown by Optokinetic tracking in a rat model of type 1 diabetes, and also decreased retinal cell death, as demonstrated by a DNA fragmentation ELISA. Further, PPARα ablation exacerbated diabetes-induced decline of visual function as demonstrated by ERG analysis. We further found that PPARα improved mitochondrial efficiency in DR, and decreased ROS production and cell death in cultured retinal neurons. Oxidative stress biomarkers were elevated in diabetic Pparα^-/- mice, suggesting increased oxidative stress. Mitochondrially mediated apoptosis and oxidative stress secondary to mitochondrial dysfunction contribute to neurodegeneration in DR. Taken together, these findings identify a robust neuroprotective effect for PPARα in DR, which may be due to improved mitochondrial function and subsequent alleviation of energetic deficits, oxidative stress and mitochondrially mediated apoptosis.

Deciphering glycomics and neuroproteomic alterations in experimental traumatic brain injury: Comparative analysis of aspirin and clopidogrel treatment

As populations age, the number of patients sustaining traumatic brain injury (TBI) and concomitantly receiving preinjury antiplatelet therapy such as aspirin (ASA) and clopidogrel (CLOP) is rising. These drugs have been linked with unfavorable clinical outcomes following TBI, where the exact mechanism(s) involved are still unknown. In this novel work, we aimed to identify and compare the altered proteome profile imposed by ASA and CLOP when administered alone or in combination, prior to experimental TBI. Furthermore, we assessed differential glycosylation PTM patterns following experimental controlled cortical impact model of TBI, ASA, CLOP, and ASA + CLOP. Ipsilateral cortical brain tissues were harvested 48 h postinjury and were analyzed using an advanced neuroproteomics LC-MS/MS platform to assess proteomic and glycoproteins alterations. Of interest, differential proteins pertaining to each group (22 in TBI, 41 in TBI + ASA, 44 in TBI + CLOP, and 34 in TBI + ASA + CLOP) were revealed. Advanced bioinformatics/systems biology and clustering analyses were performed to evaluate biological networks and protein interaction maps illustrating molecular pathways involved in the experimental conditions. Results have indicated that proteins involved in neuroprotective cellular pathways were upregulated in the ASA and CLOP groups when given separately. However, ASA + CLOP administration revealed enrichment in biological pathways relevant to inflammation and proinjury mechanisms. Moreover, results showed differential upregulation of glycoproteins levels in the sialylated N-glycans PTMs that can be implicated in pathological changes. Omics data obtained have provided molecular insights of the underlying mechanisms that can be translated into clinical bedside settings.

Hypoxia-inducible factor-1α regulates the expression of L-type voltage-dependent Ca(2+) channels in PC12 cells under hypoxia

Hypoxia is an important factor in regulation of cell behavior both under physiological and pathological conditions. The mechanisms of hypoxia-induced cell death have not been completely elucidated yet. It is well known that Ca(2+) is critically related to cell survival. Hypoxia-inducible factor-1α (HIF-1α) is a core regulatory factor during hypoxia, and L-type voltage-dependent Ca(2+) channels (L-VDCCs) have been reported to play a critical role in cell survival. This study was conducted to explore the relationship between L-VDCC expression and HIF-1α regulation in PC12 cells under hypoxia. PC12 cells were treated at 20 or 3 % O2 to observe its proliferation and the intracellular calcium concentration. Then, we detected the protein expression of HIF-1α and L-VDCCs subtypes, Cav1.2 and Cav1.3. At last, to verify the relationship between HIF-1α and Cav1.2 and Cav1.3, we got the expression of Cav1.2 and Cav1.3 with Western blot and luciferase report gene assays after PC12 cells were treated by echinomycin, which is an HIF-1α inhibitor. Compared with 20 % O2 (normoxia), 3 % O2 (hypoxia) inhibited cell proliferation, increased the intracellular calcium concentration, and induced protein expression of HIF-1α. The protein expression of two L-VDCCs subtypes expressed in the nervous system, Cav1.2 and Cav1.3, was upregulated by hypoxia and reduced dose dependently by treatment with echinomycin, a HIF-1α inhibitor. Luciferase report gene assays showed that the expression of Cav1.2 and Cav1.3 genes was augmented under 3 % O2. However, echinomycin only slightly and dose dependently decreased expression of the Cav1.2 gene, but not that of the Cav1.3 gene. These data indicated that Cav1.2 might be regulated by HIF-1α as one of its downstream target genes and involved in regulation of PC12 cells death under hypoxia.

CNTF Gene Therapy Confers Lifelong Neuroprotection in a Mouse Model of Human Retinitis Pigmentosa

The long-term outcome of neuroprotection as a therapeutic strategy for preventing cell death in neurodegenerative disorders remains unknown, primarily due to slow disease progression and the inherent difficulty of assessing neuronal survival in vivo. Employing a murine model of retinal disease, we demonstrate that ciliary neurotrophic factor (CNTF) confers life-long protection against photoreceptor degeneration. Repetitive retinal imaging allowed the survival of intrinsically fluorescent cone photoreceptors to be quantified in vivo. Imaging of the visual cortex and assessment of visually-evoked behavioral responses demonstrated that surviving cones retain function and signal correctly to the brain. The mechanisms underlying CNTF-mediated neuroprotection were explored through transcriptome analysis, revealing widespread upregulation of proteolysis inhibitors, which may prevent cellular/extracellular matrix degradation and complement activation in neurodegenerative diseases. These findings provide insights into potential novel therapeutic avenues for diseases such as retinitis pigmentosa and amyotrophic lateral sclerosis, for which CNTF has been evaluated unsuccessfully in clinical trials.

Gene transcription patterns and energy reserves in Daphnia magna show no nanoparticle specific toxicity when exposed to ZnO and CuO nanoparticles

There is still a lot of contradiction on whether metal ions are solely responsible for the observed toxicity of ZnO and CuO nanoparticles to aquatic species. While most experiments have studied nanoparticle effects at organismal levels (e.g. mortality, reproduction), effects at lower levels of biological organization may clarify the role of metal ions, nanoparticles and nanoparticle aggregates. In this study, the effect of ZnO and CuO nanoparticles was tested at two lower levels: energy reserves and gene transcription and compared with zinc and copper salts. Daphnia magna was exposed during 96h to 10% immobilization concentrations of all chemicals, after which daphnids were sampled for determination of glycogen, lipid and protein concentration and for a differential gene transcription analysis using microarray. The dissolved, nanoparticle and aggregated fraction in the medium was characterized. The results showed that ZnO nanoparticles had largely dissolved directly after addition to the test medium. The CuO nanoparticles mostly formed aggregates, while only a small fraction dissolved. The exposure to zinc (both nano and metal salt) had no effect on the available energy reserves. However, in the copper exposure, the glycogen, lipid and protein concentration in the exposed daphnids was lower than in the unexposed ones. When comparing the nanoparticle (ZnO or CuO) exposed daphnids to the metal salt (zinc or copper salt) exposed daphnids, the microarray results showed no significantly differentially transcribed gene fragments. The results indicate that under the current exposure conditions the toxicity of ZnO and CuO nanoparticles to D. magna is solely caused by toxic metal ions.

SERPINA3K plays antioxidant roles in cultured pterygial epithelial cells through regulating ROS system

We recently demonstrated that SERPINA3K, a serine proteinase inhibitor, has antioxidant activity in the cornea. Here we investigated the antioxidant effects of SERPINA3K on the pterygial, which is partially caused by oxidative stress in pathogenesis. The head part of primary pterygial tissue was dissected and then cultured in keratinocyte serum-free defined medium (KSFM). The cultured pterygial epithelial cells (PECs) were treated with SERPINA3K. The cell proliferation and migration of PECs were measured and analyzed. Western blot and quantitative real-time polymerase chain reaction (PCR) assay were performed. It showed that SERPINA3K significantly suppressed the cell proliferation of PECs in a concentration-dependent manner, compared with cultured human conjunctival epithelial cells. SERPINA3K also inhibited the cell migration of PECs. Towards its underlying mechanism, SERPINA3K had antioxidant activities on the PECs by significantly inhibiting NADPH oxidase 4 (NOX4), which is an important enzyme of ROS generation, and by elevating the levels of key antioxidant factors of ROS: such as NAD(P)H dehydrogenase (quinone 1) (NQO1), NF-E2–related factor-2 (NRF2) and superoxide dismutases (SOD2). Meanwhile, SERPINA3K down-regulated the key effectors of Wnt signaling pathway: β-catenin, nonphospho-β-catenin, and low-density lipoprotein receptor-related protein 6 (LRP6). We provided novel evidence that SERPINA3K had inhibitory effects on pterygium and SERPINA3K played antioxidant role via regulating the ROS system and antioxidants.

Protective and antioxidant effects of PPARα in the ischemic retina

PURPOSE

Previous studies have demonstrated that peroxisome proliferator-activated receptor-alpha (PPARα) agonists have therapeutic effects in diabetic retinopathy, although the mechanism of action remains incompletely understood. The purpose of this study was to evaluate PPARα's protective effects in the ischemic retina, and to delineate its molecular mechanism of action.

METHODS

For the oxygen-induced retinopathy (OIR) model, wild-type (WT), and PPARα knockout (PPARα(-/-)) mice were exposed to 75% O₂ from postnatal day 7 (P7) to P12 and treated with the PPARα agonist fenofibric acid (Feno-FA) from P12 to P16. At P17, the effects of Feno-FA on retinal glial fibrillary acidic protein (GFAP) expression, apoptotic DNA cleavage, and TUNEL labeling were analyzed. Cultured retinal cells were exposed to CoCl₂ to induce hypoxia, and TUNEL staining and 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein dye were used to measure apoptosis and reactive oxygen species (ROS) generation. Western blotting was used to measure GFAP levels and cell signaling.

RESULTS

Feno-FA decreased retinal apoptosis and oxidative stress in WT but not PPARα(-/-) OIR mice. Peroxisome proliferator-activated receptor-alpha knockout OIR mice showed increased retinal cell death and glial activation in comparison to WT OIR mice. Feno-FA treatment and PPARα overexpression protected cultured retinal cells from hypoxic cell death and decreased ROS levels. Nuclear hypoxia-inducible factor-α (HIF-1α) and nicotine adenine dinucleotide phosphate oxidase-4 (Nox 4) were increased in OIR retinas and downregulated by Feno-FA in WT but not in PPARα(-/-) mice.

CONCLUSIONS

Peroxisome proliferator-activated receptor-alpha has a potent antiapoptotic effect in the ischemic retina. This protective effect may be mediated in part through downregulation of HIF-1α/Nox 4 and consequently alleviation of oxidative stress.

Calcium mediates high glucose-induced HIF-1α and VEGF expression in cultured rat retinal Müller cells through CaMKII-CREB pathway

AIM

To investigate the effects of high glucose (HG) medium on expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in cultured rat retinal Müller cells and to determine the signaling pathways mediating the effects.

METHODS

Primary cultures of retinal Müller cells were prepared from Sprague-Dawley rats, and incubated in a medium containg HG (30 mmol/L) in the presence of the membrane-permeable Ca(2+) chelator BAPTA-AM (10 μmol/L) or the CaMKII inhibitor KN93 (10 μmol/L). The levels of CaMKII, p-CaMKII, CREB, p-CREB, HIF-1α, and VEGF proteins were measured with Western blotting, while HIF-1á and VEGF mRNA levels were determined using real-time RT-PCR.

RESULTS

The stimulation of retinal Müller cell with HG for 24 h remarkably increased the expression levels of HIF-1α and VEGF. These responses were significantly inhibited in the presence of BAPTA-AM or KN93. Both BAPTA-AM and KN93 also significantly inhibited HG-induced phosphorylation of CaMKII and CREB in the cultured retinal Müller cells. Transfection of the cultured retinal Müller cells with antisense CREB oligonucleotide (300 nmol/L) was similarly effective in blocking the HG-induced increase of HIF-1α and VEGF.

CONCLUSION

HG-induced HIF-1α and VEGF expression in cultured rat retinal Müller cells depends on intracellular free Ca(2+) and activation of CaMKII-CREB pathway. The activation of CaMKII-CREB pathway by HG may be a possible mechanism underlying the pathogenesis of diabetic retinopathy.

Effect of m-3m3FBS on Ca2+ handling and viability in OC2 human oral cancer cells

The effect of 2,4,6-trimethyl-N-(meta-3-trifluoromethyl-phenyl)-benzenesulfonamide (m-3M3FBS), a presumed phospholipase C activator, on cytosolic free Ca2+ concentrations ([Ca2+]i) in OC2 human oral cancer cells is unclear. This study explored whether m-3M3FBS changed basal [Ca2+]i levels in suspended OC2 cells by using fura-2 as a Ca2+-sensitive fluorescent dye. M-3M3FBS at concentrations between 10-60 μM increased [Ca2+]i in a concentration-dependent manner. The Ca2+ signal was reduced partly by removing extracellular Ca2+. M-3M3FBS-induced Ca2+ influx was inhibited by the store-operated Ca2+ channel blockers nifedipine, econazole and SK&F96365, and by the phospholipase A2 inhibitor aristolochic acid. In Ca2+-free medium, 30 μM m-3M3FBS pretreatment inhibited the [Ca2+]i rise induced by the endoplasmic reticulum Ca2+ pump inhibitors thapsigargin and 2,5-di-tert-butylhydroquinone (BHQ). Conversely, pretreatment with thapsigargin, BHQ or cyclopiazonic acid partly reduced m-3M3FBS-induced [Ca2+]i rise. Inhibition of inositol 1,4,5-trisphosphate formation with U73122 did not alter m-3M3FBS-induced [Ca2+]i rise. At concentrations between 5 and 100 μM m-3M3FBS killed cells in a concentration-dependent manner. The cytotoxic effect of m-3M3FBS was not reversed by prechelating cytosolic Ca2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). Propidium iodide staining data suggest that m-3M3FBS (20 or 50 μM) induced apoptosis in a Ca2+-independent manner. Collectively, in OC2 cells, m-3M3FBS induced [Ca2+]i rise by causing inositol 1,4,5-trisphosphate-independent Ca2+ release from the endoplasmic reticulum and Ca2+ influx via phospholipase A2-sensitive store-operated Ca2+ channels. M-3M3FBS also induced Ca2+-independent cell death and apoptosis.

Not all sarcomas developed in irradiated tissue are necessarily radiation-induced--spectrum of disease and treatment characteristics

BACKGROUND

Sarcomas in irradiated tissue (SITs) are often considered with second cancers, although they usually present distinct dose-response, genetic and clinical patterns. The contribution of radiation in SIT development is likely, but remains unproven in many cases.

MATERIALS AND METHODS

We reviewed the literature for published data on SITs.

RESULTS

SITs incidence ranged between 0.03% and 0.2%. Median latency was 15 years. Angiosarcoma was the second most common subtype after undifferentiated sarcomas of malignant fibrous histiocytoma (MFH). C-Myc overexpression can be used to identify radiation-induced angiosarcoma, and a recently described transcriptomic signature of genes involved in chronic oxidative stress and mitochondrial dysfunction may indicate radiation causality. Osteosarcomas were often associated with genetic predisposition. Five-year survival rates rarely exceeded 30% because the therapeutic possibilities were often limited by the first cancer. Chemotherapy response may differ from that of de novo sarcomas.

CONCLUSION

SITs present different characteristics from non-sarcomatoid second cancers. Reporting of SIT cases and the establishment of tissue and serum banks is necessary to better understand and validate the recently discovered radiation signature.

Occludin protein family: oxidative stress and reducing conditions

The occludin-like proteins belong to a family of tetraspan transmembrane proteins carrying a marvel domain. The intrinsic function of the occludin family is not yet clear. Occludin is a unique marker of any tight junction and is found in polarized endothelial and epithelial tissue barriers, at least in the adult vertebrate organism. Occludin is able to oligomerize and to form tight junction strands by homologous and heterologous interactions, but has no direct tightening function. Its oligomerization is affected by pro- and antioxidative agents or processes. Phosphorylation of occludin has been described at multiple sites and is proposed to play a regulatory role in tight junction assembly and maintenance and, hence, to influence tissue barrier characteristics. Redox-dependent signal transduction mechanisms are among the pathways modulating occludin phosphorylation and function. This review discusses the novel concept that occludin plays a key role in the redox regulation of tight junctions, which has a major impact in pathologies related to oxidative stress and corresponding pharmacologic interventions.

Anti-angiogenic and anti-inflammatory effects of SERPINA3K on corneal injury

SERPINA3K is a member of the serine proteinase inhibitor (SERPIN) family. Here we evaluated the therapeutic effects of SERPINA3K on neovascularization and inflammation in a rat cornea alkali burn model that is commonly employed to study corneal wounding. Topical treatment of the injured rat cornea with SERPINA3K (20 µg/eye/day) for 7 days significantly decreased the neovascular area, compared with the groups treated with BSA or PBS. The SERPINA3K treatment also ameliorated the corneal inflammation as evaluated by the inflammatory index. Furthermore, SERPINA3K enhanced the recovery of corneal epithelium after the alkali injury. Toward the mechanism of action, SERPINA3K down-regulated the expression of the pro-angiogenic and pro-inflammatory factors, vascular endothelial growth factor and tumor necrosis factor-α and up-regulated the expression of the anti-angiogenic factor, pigment epithelium-derived factor. SERPINA3K specifically inhibited growth of vascular endothelial cells. Meanwhile, SERPINA3K significantly up-regulated the expression of EGFR in the corneal epithelium. These findings suggest that SERPINA3K has therapeutic potential for corneal inflammation and NV.

Identification of Unique Blood and Urine Biomarkers in Influenza Virus and Staphylococcus aureus Co-infection: A Preliminary Study

Each year, there are estimated to be approximately 200,000 hospitalizations and 36,000 deaths due to influenza in the United States. Reports have indicated that most deaths are not directly due to influenza virus, but to secondary bacterial pneumonia, predominantly staphylococcal in origin. Here we identify the presence of candidate blood and urine biomarkers in mice with Staphyococcus aureus and influenza virus co-infection. In this pilot study, mice were grouped into four treatments: co-infected with influenza virus and S. aureus, singly infected with influenza virus or S. aureus, and a control group of uninfected mice (PBS treated). Gene expression changes were identified by DNA-microarrays from blood samples taken at day five post infection. Proteomic changes were obtained from urine samples collected at three and five days post infection using 2-D DIGE followed by protein ID by mass spectrometry. Differentially expressed genes and/or proteins were identified as candidate biomarkers for future validation in larger studies.

Wnt pathway antagonists and angiogenesis

Dysregulation of the Wnt pathway has been extensively studied in multiple diseases, including some angiogenic disorders. Wnt signaling activation is a major stimulator in pathological angiogenesis and thus, Wnt antagonists are believed to have therapeutic potential for neovascular disorders. Actually, some Wnt antagonists have been identified directly from the anti-angiogenic factor family. This review summarizes the recent progress toward understanding of the roles of Wnt pathway antagonists in angiogenic regulation and their mechanism of action, and exploring their therapeutic potential.

Blocking the Wnt pathway, a unifying mechanism for an angiogenic inhibitor in the serine proteinase inhibitor family

The Wnt pathway regulates multiple biological and pathological processes including angiogenesis and inflammation. Here we identified a unique inhibitor of the Wnt pathway, SERPINA3K, a serine proteinase inhibitor with anti-inflammatory and angiogenic activities. SERPINA3K blocked the Wnt pathway activation induced by a Wnt ligand and by diabetes. Coprecipitation and ligand binding assay showed that SERPINA3K binds to low-density lipoprotein receptor-like protein 6 (LRP6) with a K(d) of 10 nM, in the range of its physiological concentration in the retina. Under the same conditions, SERPINA3K did not bind to the frizzled (Fz) receptor or low-density lipoprotein receptor. Further, SERPINA3K bound to LRP6 at the extracellular domain and blocked its dimerization with the Fz receptor induced by a Wnt ligand. The antagonizing activity of SERPINA3K to LRP6 was further confirmed by Xenopus axis duplication assay. These results suggest that SERPINA3K is a high-affinity, endogenous antagonist of LRP6. The blockade of Wnt signaling may represent a unifying mechanism for the anti-inflammatory and anti-angiogenic effects of SERPINA3K.

Prediction of diabetic retinopathy: role of oxidative stress and relevance of apoptotic biomarkers

Diabetic retinopathy (DR) is the foremost cause of blindness in working-aged worldwide; it is characterized by vascular and neuronal degeneration. Features of DR include leukocyte adhesion, increased vascular permeability, neovascularization and neuronal cell death. Early diagnosis and intervention are important to prevent or at least ameliorate the development of DR. Recent reports indicate that pathophysiological mechanisms leading to diabetic retinopathy include oxidative stress and retinal cell death cascades. Circulating biomarkers of oxidative stress such as malondialdehyde (MDA), thiobarbituric acid reacting substances (TBARS), conjugated diene (CD), advanced oxidation protein products (AOPP), protein carbonyl, 8-hydroxydeoxyguanosin (8-OHdG), nitrotyrosine, and F(2) isoprostanes and pro-apoptosis molecules (caspase-3, Fas, and Bax) are associated with increased susceptibility to develop DR in diabetic subjects. Thus, identification of oxidative stress and cell death biomarkers in diabetic patients could be in favor of predicting, diagnosis, and prevention of DR, and to target for novel therapeutic interventions.

Combination of host susceptibility and Mycobacterium tuberculosis virulence define gene expression profile in the host

Progression and outcome of tuberculosis is governed by extensive crosstalk between pathogen and host. Analyses of global changes in gene expression during immune response to infection with Mycobacterium tuberculosis (M.tb) can help identify molecular markers of disease state and progression. Global distribution of M.tb strains with different degrees of virulence and drug resistance, especially for the immunocompromised host, make closer analyses of host responses more pressing than ever. Here, we describe global transcriptional responses of inducible nitric oxide synthase-deficient (iNOS(-/-)) and WT mice infected with two related M.tb strains of markedly different virulence, namely the M.tb laboratory strains H37Rv and H37Ra. Both hosts exhibited highly similar resistance to infection with H37Ra. In contrast, iNOS(-/-) mice rapidly succumbed to H37Rv, whereas WT mice developed chronic course of disease. By differential analyses, virulence-specific changes in global host gene expression were analyzed to identify molecular markers characteristic for chronic versus acute infection. We identified several markers unique for different stages of disease progression and not previously associated with virulence-specific host responses in tuberculosis.

Effect of m-3M3FBS on Ca(2+) movement in Madin-Darby canine renal tubular cells

The effect of 2,4,6-trimethyl-N-(meta-3-trifluoromethyl-phenyl)-benzenesulfonamide (m-3M3FBS), a presumed phospholipase C (PLC) activator, on cytosolic free Ca(2+) concentrations ([Ca( 2+)](i)) in Madin-Darby canine kidney (MDCK) cells is unclear. This study explored whether m-3M3FBS changed basal [Ca(2+)](i) levels in suspended MDCK cells using fura-2 as a Ca(2+)-sensitive fluorescent dye. M-3M3FBS at concentrations between 0.1 and 20 microM increased [Ca(2+)](i) in a concentration-dependent manner. The Ca(2+) signal was decreased by removing extracellular Ca(2+). M-3M3FBS-induced Ca(2+) influx was inhibited by the store-operated Ca(2+) channel blockers nifedipine, econazole, and SK&F96365, and by the phospholipase A2 inhibitor aristolochic acid. In Ca(2+)-free medium, 20-microM m-3M3FBS pretreatment abolished the [Ca(2+)](i) rise induced by the endoplasmic reticulum Ca(2+) pump inhibitors thapsigargin (TG) and cyclopiazonic acid (CPA). Conversely, pretreatment with TG or CPA partly reduced m-3M3FBS-induced [Ca(2+)](i) rise. The inhibition of PLC with U73122 did not alter m-3M3FBS-induced [Ca(2+)](i) rise. Collectively, in MDCK cells, m-3M3FBS induced [Ca(2+)](i) rises by causing PLC-independent Ca(2+) release from the endoplasmic reticulum and Ca(2+) influx via store-operated Ca(2+) channels and other unidentified Ca(2+) channels.