Increased Retinal Ganglion Cell Survival by Exogenous IL-2 Depends on IL-10, Dopamine D1 Receptors, and Classical IL-2/IL-2R Signaling Pathways

Ouabain Counteracts Retinal Ganglion Cell Death Through Modulation of BDNF and IL-1 Signaling Pathways

Background: Ouabain is a steroid hormone that binds to the sodium pump (Na+, K+-ATPase) at physiological (nanomolar) concentrations, activating different signaling pathways. This interaction has been shown to prevent the axotomy-induced death of retinal ganglion cells (RGCs), although the underlying mechanisms remain unclear. Objective: In this study, we investigated potential mechanisms by which ouabain promotes RGC survival using primary cultures of rat neural retina. Results: Our findings indicate that ouabain regulates brain-derived neurotrophic factor (BDNF) signaling in retinal cells via matrix metalloproteinase-9-mediated processing of proBDNF to mature BDNF (mBDNF) and by increasing the phosphorylation of the mBDNF receptor, tropomyosin-related receptor kinase B. Ouabain also enhances the maturation of interleukin (IL)-1β through the increased activation of caspase-1, which mediates the processing of proIL-1β into IL-1β, and transiently upregulates both IL-1 receptor and IL-1 receptor antagonist (IL-1Ra). Treatment using either IL-1β or IL-1Ra alone is sufficient to enhance RGC survival similarly to that achieved with ouabain. Finally, we further show that ouabain prevents RGC death through a complex signaling mechanism shared by BDNF and IL-1β, which includes the activation of the Src and protein kinase C pathways. Conclusions: Collectively, these results suggest that ouabain stimulates the maturation and signaling of both BDNF and IL-1β, which act as key mediators of RGC survival.

Multiple Roles of cAMP in Vertebrate Retina

cAMP is a key regulatory molecule that controls many important processes in the retina, including phototransduction, cell development and death, growth of neural processes, intercellular contacts, retinomotor effects, and so forth. The total content of cAMP changes in the retina in a circadian manner following the natural light cycle, but it also shows local and even divergent changes in faster time scales in response to local and transient changes in the light environment. Changes in cAMP might also manifest or cause various pathological processes in virtually all cellular components of the retina. Here we review the current state of knowledge and understanding of the regulatory mechanisms by which cAMP influences the physiological processes that occur in various retinal cells.

Aqueous humor cytokine levels are associated with the severity of visual field defects in patients with primary open-angle glaucoma

BACKGROUND

To evaluate the aqueous humor (AH) levels of cytokines in primary open-angle glaucoma (POAG) patients and cataract patients.

METHODS

Thirty-eight POAG patients and 26 cataract patients were recruited. Peripheral blood (PB) was collected from each subject. The POAG group was divided into 2 subgroups according to the severity of visual field defects. The cutoff point of the mean deviation (MD) of the visual field was -12 dB. AH was obtained at the time of anterior chamber puncture during cataract or glaucoma surgery by using a 27-gauge needle attached to a microsyringe. AH and PB levels of interleukin-2 (IL-2), tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta2 (TGF-β2) and IL-4 were assayed by enzyme-linked immunosorbent assay. Postoperative intraocular pressures (IOPs) of POAG patients were recorded during the follow-up period.

RESULTS

TNF-α and TGF-β2 showed significantly higher AH levels in the POAG group than in the cataract group (P < 0.001 and P = 0.001, respectively). For the POAG group, preoperative IOPs were significantly positively correlated with AH levels of TNF-α (r² = 0.129, P = 0.027) and TGF-β2 (r² = 0.273, P = 0.001). AH levels of TGF-β2 were significantly different among cataract patients, POAG patients with MD> -12 dB and POAG patients with MD≤ -12 dB (P = 0.001). AH levels of TNF-α were significantly positively associated with IOP reduction after trabeculectomy (P = 0.025). AH and PB levels of cytokines were not related to the long-term success of trabeculectomy.

CONCLUSION

The levels of TNF-α and TGF-β2 showed different profiles in POAG patients and cataract patients. AH levels of TGF-β2 were correlated with the severity of glaucomatous neuropathy in POAG patients. The findings suggest possible roles for cytokines in the pathogenesis and development of POAG.

Mahuang Xixin Fuzi decoction protects the BALB/c-nude mice infected with influenza A virus by reducing inflammatory cytokines storm and weakly regulating SIgA immune response

ETHNOPHARMACOLOGICAL RELEVANCE

Mahuang Xixin Fuzi Decoction (MXF), as a classical prescription of traditional Chinese medicine (TCM), has been used to treat the immunocompromised individuals infected with influenza A virus (IAV).

AIM OF THE STUDY

The study aims to explore the regulatory of MXF on inflammation and secretory immunoglobulin A (SIgA) antibodies immune response in BALB/c-nude mice infected with IAV.

MATERIALS AND METHODS

The BALB/c-nude mice were infected with IAV, then different dosages of MXF were orally administrated to the mice. The weight, rectal temperature, spontaneous activity, spleen index, lung index, pathological changes of lung tissues, and the relative mRNA expression level of H1N1 M gene were measured for the purpose of valuing the antiviral effect of MXF. The expression levels of cytokines in lungs and immunoglobulin A (IgA) in serum of BALB/c-nude mice were determined with Cytometric Bead Array System (CBA). SIgA in bronchoalveolar lavage fluids (BALF) was detected with Enzyme-linked Immunosorbent Assay (ELISA). The mRNA and protein expression levels of B cell activating factor (BAFF), chemokine receptors 10 (CCR10), and polymeric immunoglobulin receptor (pIgR) in the lung tissues, which are related to the secretion of SIgA, were determined by using RT-PCR and Western blot.

RESULTS

MXF could alleviate the clinical features and reduce the severity of viral lung lesions, including improving the body weight, rectal temperature and spontaneous activity of nude mice infected with IAV, increasing spleen index, decreasing lung index, alleviating pathological damage, and decreasing the relative expression level of H1N1 M gene. Levels of pro-inflammatory cytokines, including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-2 (IL-2), interleukin-12p70 (IL-12p70), and interleukin-17A (IL-17A) were also significantly decreased after treatment with MXF. Interferon-γ (IFN-γ), an antiviral cytokine, was significantly up-regulated in high dose MXF (3.12 g/kg) group. Moreover, after MXF treatment, the expressions of SIgA in BALF and IgA in serum were both at relatively low levels. And the mRNA and protein expressions of BAFF, CCR10, and pIgR were significantly decreased after treatment with MXF.

CONCLUSIONS

MXF has obviously protective effects on BALB/c-nude mice infected with IAV by inhibiting virus replication, calming inflammatory cytokine storm, and regulating SIgA immune response weakly.

Insulin-like growth factor-1 stimulates retinal cell proliferation via activation of multiple signaling pathways

Insulin-like growth factor-1 (IGF-1) plays critical roles in the development of the central nervous system (CNS), including the retina, regulating cell proliferation, differentiation, and survival. Here, we investigated the role of IGF-1 on retinal cell proliferation using primary cultures from rat neural retina. Our data show that IGF-1 stimulates retinal cell proliferation and regulates the expression of neurotrophic factors, such as interleukin-4 and brain-derived neurotrophic factor. In addition, our results indicates that IGF-1-induced retinal cell proliferation requires activation of multiple signaling pathways, including phosphatidylinositol 3-kinase, protein kinase Src, phospholipase-C, protein kinase C delta, and mitogen-activated protein kinase pathways. We further show that activation of matrix metalloproteinases and epidermal growth factor receptor is also necessary for IGF-1 enhancing retinal cell proliferation. Overall, these results unveil potential mechanisms by which IGF-1 ensures retinal cell proliferation and support the notion that manipulation of IGF-1 signaling may be beneficial in CNS disorders associated with abnormal cell proliferation.

Ouabain Effects on Human Anaplastic Thyroid Carcinoma 8505C Cells

Anaplastic thyroid carcinoma (ATC) is a rare, but aggressive, carcinoma derived from follicular cells. While conventional treatments may improve patients' survival, the lethality remains high. Therefore, there is an urgent need for more effective ATC treatments. Cardiotonic steroids, such as ouabain, have been shown to have therapeutic potential in cancer treatment. Thus, we aimed to evaluate ouabain's effects in human anaplastic thyroid cells. For this, 8505C cells were cultured in the presence or absence of ouabain. Viability, cell death, cell cycle, colony formation and migratory ability were evaluated in ouabain-treated and control 8505C cells. The expression of differentiation and epithelial-to-mesenchymal transition (EMT) markers, as well as IL-6, TGFb1 and their respective receptors were also quantified in these same cells. Our results showed that ouabain in vitro decreased the number of viable 8505C cells, possibly due to an inhibition of proliferation. A reduction in migration was also observed in ouabain-treated 8505C cells. In contrast, decreased mRNA levels of PAX8 and TTF1 differentiation markers and increased levels of the N-cadherin EMT marker, as well as IL-6 and TGFb1, were found in ouabain-treated 8505C cells. In short, ouabain may have anti-proliferative and anti-migratory effect on 8505C cells, but maintains an aggressive and undifferentiated profile.

Interleukin-4 activates divergent cell-intrinsic signals to regulate retinal cell proliferation induced by classical growth factors

In the developing retina, precise coordination of cell proliferation, differentiation, and survival is essential for proper retinal maturation and function. We have previously reported evidence that interleukin-4 (IL-4) plays critical roles in neuronal differentiation and survival during retinal development. However, little is known about the role of IL-4 on retinal cell proliferation. In the current study, we investigated if IL-4 regulates cell proliferation induced by epidermal growth factor (EGF) and by fibroblast growth factor 2 (FGF2) in primary retinal cell cultures obtained from newborn rats. First, we show that EGF and FGF2 act as mitogens for glial cells, increasing proliferation of these cells in the retina. EGF- and FGF2-induced mitogenesis requires activation of distinct cell-intrinsic signals. In retinal cells exposed to FGF2, IL-4 downregulates p53 levels (a protein whose activation induces cell-cycle arrest) and increases mitogenic responsiveness to FGF2 through activation of protein kinase A (PKA) pathway. Conversely, in retinal cells exposed to EGF, IL-4 downregulates cyclin D1 levels (a protein required for cell-cycle progression), upregulates p53 levels, and decreases mitogenic responsiveness to EGF. The inhibitory effect induced by IL-4 on retinal cells exposed to EGF requires activation of Janus kinase 3 (JAK3), but not activation of PKA. Based on previous and current findings, we propose that IL-4 serves as a node of signal divergence, modulating multiple cell-intrinsic signals (e.g., cyclin D1, p53, JAK3, and PKA) and mitogenic responsiveness to cell-extrinsic signals (e.g., FGF2 and EGF) to control cell proliferation, differentiation, and survival during retinal development.

Expression of Interleukin-2 receptor subunit gamma (IL-2Rγ) and its binding with IL-2 induced activation of CD4 T lymphocytes in flounder (Paralichthys olivaceus)

Interleukin-2 receptor (IL-2R), as the specific ligand of interleukin-2 (IL-2), binds to IL-2 and transmits signals and then can induce the proliferation of T lymphocytes in mammals. In this paper, the subunit of IL-2R in flounder (Paralichthys olivaceus), interleukin-2 receptor subunit gamma (IL-2Rγ) was cloned, and polyclonal antibodies (Abs) against its extracellular region were produced, then the expression of flounder IL-2Rγ (fIL-2Rγ) at transcriptional and cellular levels were characterized. Moreover, the interaction of flounder IL-2 (fIL-2) with fIL-2Rγ was investigated, and the variations on CD4+/IL-2Rγ+ cells in flounder after treatment with recombinant IL-2 (rIL-2), anti-IL-2Rγ Abs were detected, respectively. The results showed that fIL-2Rγ protein had a typical fibronectin type III (FN3) domain. The Abs could specifically recognize native fIL-2Rγ molecules at 39.9 kDa. FIL-2Rγ was localized on both T and B lymphocytes, and the percentages of CD4+/IL-2Rγ+ and IgM+/IL-2Rγ+ lymphocytes were high in spleen. In addition, pBiFC-VN173-IL-2Rγ plasmids could bind to pBiFC-VC155-IL-2 plasmids. The percentage of CD4+/IL-2Rγ+ lymphocytes was significantly decreased after blocking with anti-IL-2Rγ Abs both in vivo and in vitro. In the meantime, four T cell markers genes and six IL-2-IL-2R pathway genes were down-regulated in anti-IL-2Rγ Abs group. These results first demonstrated that fIL-2Rγ molecules were expressed on both T and B lymphocytes in flounder, and the bond between fIL-2Rγ and fIL-2 activated the CD4 T lymphocytes. This study gave a new sight into the exploration of IL-2R function on T lymphocytes proliferation in fish.