Association between anti-fibrillin-2 protein induced retinal degeneration via intravitreous delivery and activated TGF-ß signalling in mice.

Fibrillin-2 (FBN2) is a major component of tissue microfibrils, and the decrease of FBN2 perturbs the signalling events mediated by transforming growth factor-ß (TGF-ß), thereby playing a role in macular degeneration. However, the association between the retinal degeneration resulting from the abnormality of FBN2 and the activation of TGF-ß signalling has not been fully addressed. In the present study, the mice were divided into a normal control group (NC group), a phosphate-buffered saline (PBS) injection group (PBS group), and an anti-FBN2 protein injection group (anti-FBN2 group), and the mice in PBS and anti-FBN2 groups received the relevant treatment via the intravitreal injection once a week for three consecutive weeks. One week later after injection, the retinal morphology and visual function of the fundus were detected. Further, the expression of FBN2, TGF-ß1, TGF-ß2 and TGF-ß3 in retina was measured using quantitative polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA), respectively. As a result, fundus examination suggests that after intravitreous injection of anti-FBN2 protein, there were a large patchy yellow white degeneration region and numerous pigmentations in the retina in anti-FBN2-treated mice; by contrast, there was no apparent change in mice from the NC and PBS groups. The retina suffered markedly damage, and the thickness of whole retina and outer nuclear layer markedly thinned. The expression of FBN2 was decreased whereas the levels of TGF-ß1, TGF-ß2 and TGF-ß3 were upregulated. Together, our findings indicate that the intravitreous delivery of anti-FBN2 protein could induce retina degeneration in mice, accompanied by the higher activated TGF-ß. The retinal degeneration mouse model established will provide a platform for the investigation of the retinal diseases.

Disrupted potassium ion homeostasis in ciliary muscle in negative lens-induced myopia in Guinea pigs.

Myopia is a main cause of preventable or treatable visual impairment, it has become a major public health issue due to its increasingly high prevalence worldwide. Currently, it is confirmed that the development of myopia is associated with the disorders of accommodation. As a dominant factor for accommodation, ciliary muscle contraction/relaxation can regulate the physiological state of the lens and play a crucial role in the development of myopia. To investigate the relationship between myopia and ciliary muscle, the guinea pigs were randomly divided into a normal control (NC) group and a negative lens-induced myopia (LIM) group, and the animals in each group were further randomly assigned into 2-week (n = 18) and 4-week (n = 21) subgroups in accordance with the duration of myopic induction of 2 and 4 weeks, respectively. In the present study, right eyes of the animals in LIM group were covered with -6.0 D lenses to induce myopia. Next, we performed the haematoxylin and eosin (H&E) staining to observe the pathological change of ciliary muscle, determined the contents of adenosine triphosphate (ATP) and lactate acid (LA), and measured the Na+/K+-ATPase expression and activity in ciliary muscles in both NC and LIM groups. Moreover, we also analyzed the potassium ion (K+) flux in ciliary muscles from 4-week NC and LIM guinea pigs. As a result, we found that the arrangements of ciliary muscles in LIM guinea pigs were broken, dissolved or disorganized; the content of ATP decreased, whereas the content of LA increased in ciliary muscles from LIM guinea pigs. Monitoring of K+ flux in ciliary muscles from LIM guinea pigs demonstrated myopia-triggered K+ influx. Moreover, we also noted a decreased expression of Na+/K+-ATPase (Atp1a1) at both mRNA and protein levels and reduced activity in ciliary muscles from LIM guinea pigs. Overall, our results will facilitate the understanding of the mechanism associated with inhibitory Na+/K+-ATPase in lens-induced myopia and which consequently lead to the disorder of microenvironment within ciliary muscles from LIM guinea pigs, paving the way for a promising adjuvant approach in treating myopia in clinical practice.

Alternation of Resting-State Functional Connectivity Between Visual Cortex and Hypothalamus in Guinea Pigs With Experimental Glucocorticoid Enhanced Myopia After the Treatment of Electroacupuncture.

Excessive glucocorticoids (GC) may lead to the aggravation of several basic diseases including myopia, due to plasma hormone imbalances associated with the hypothalamic-pituitary-adrenal axis (HPAA). Electroacupuncture (EA) is an effective therapeutic method to treat many diseases, although it remains unclear whether EA at acupoints on the foot or back would be effective in treating eye diseases. It was recently found that visual cortex activity for responses to visual stimuli with spatial frequency and resting-state functional connectivity (FC) between the supramarginal gyrus and rostrolateral prefrontal cortex was significantly reduced in patients with high myopia. The present study aims to investigate the role of the alternation of resting-state FC among the bilateral visual cortex and hypothalamus in exerting anti-myopia effects of EA in GC-enhanced lens-induced myopic (LIM) guinea pigs such that the mechanisms of EA to treat GC-enhanced myopia at Shenshu (BL23) acupoints can be probed. To confirm the effects of EA, ocular parameters including axial length and GC-associated physiological parameters such as animal appearance, behavior, bodyweight, and levels of four HPAA-associated plasma hormones [free triiodothyronine (FT3), free thyroxine (FT4), estradiol (E2), and testosterone (T)] were also collected. Increased resting-state FC between the left and right visual cortex was detected in GC-enhanced lens-induced myopic guinea pigs with EA at BL23 acupoints (LIM+GC+EA) guinea pigs compared to GC-enhanced lens-induced myopic guinea pigs with EA at sham acupoints (LIM+GC+Sham) guinea pigs, as well as suppressed myopia and recovery of symptoms initially caused by overdose of GC. Recovered symptoms included improved animal appearance, behavior, bodyweight, and HPAA-associated plasma hormone levels were observed after 4 weeks of EA treatment. In contrast, the LIM+GC+Sham group showed decreased FC with elongation of axial length for myopization as compared to the control group and LIM group and exhibited a deterioration in physiological parameters including reduced body weight and balance disruption in the four measured HPAA-associated plasma hormones. Our findings suggest that EA could effectively treat GC-enhanced myopia by increasing resting-state FC between the left and right visual cortices, which may be pivotal to further understanding the application and mechanisms of EA in treating GC-enhanced myopia.

[Fibrillin-2 gene mutations associated with hereditary connective tissue diseases].

Fibrillin-2 (FBN2) is an important component of microfibers which are involved in the formation of elastic fibers in connective tissue throughout the human body. Hereditary connective tissue diseases may result from genetic mutations of FBN2 causing heterogeneity of fibrin. Genetic mutations of FBN2 are associated with a variety of hereditary connective tissue diseases including Congenital Contractural Arachnodactyl (CCA), Macular Degeneration (MD), and myopathy. Studies have shown that the FBN2 gene is recognized as the only pathogenic gene related to CCA and that CCA patients have different clinical presentations depending on the identified genetic mutations at different FBN2 sites. In this review, we summarize the roles of FBN2, its mutations and impact on the physiological and pathological processes of many hereditary connective tissue diseases. We include brief descriptions of clinical manifestations of these diseases providing a basis for further exploration of the specific molecular mechanism of FBN2 gene mutation pathogenesis which provides a theoretical basis for the therapy and medications for refractory diseases caused by FBN2 gene mutation.

Activation of the Notch signaling pathway disturbs the CD4+/CD8+, Th17/Treg balance in rats with experimental autoimmune uveitis.

OBJECTIVE AND DESIGN: The present study aimed to investigate the relationship between the disturbed balance of CD4+/CD8+, Th17/Treg and the activation of the Notch signaling pathway in experimental autoimmune uveitis (EAU). METHODS: An EAU rat model was induced in Lewis rats, and pathology analysis was performed by hematoxylin and eosin (H&E) staining. CD4+, CD8+, Th17, and Treg levels in spleen, lymph nodes and eye tissues were determined by flow cytometry. Meanwhile, the expression of Notch1, DLL4, IL-10, and IL-17 was determined by quantitative polymerase chain reaction (Q-PCR) and enzyme-linked immunosorbent assay (ELISA). In addition, the inhibitory effect of N-(N-(3,5-difluorophenacetyl-L-alanyl))-S-phenylglycine t-butyl ester (DAPT) on Th17 differentiation by Notch signaling in vitro was further investigated using T lymphocytes from EAU rats on day 12 post-immunization by flow cytometry. RESULTS: The pathological results showed that inflammatory cell infiltration occurred in ocular tissues in EAU rats. The CD4+/CD8+ and Th17/Treg ratios in EAU rats were apparently higher than those in normal control individuals. Q-PCR and ELISA analyses indicated the expression of Notch1, DLL4, IL-10, and IL-17 in EAU rats gradually increased on day 6 after immunization, peaked on day 12, and then gradually decreased. The dynamic trends in Notch1 and DLL4 expression in EAU rats were identical to those of CD4+/CD8+ and Th17/Treg levels. DAPT can significantly inhibit the activation of Notch signaling, decrease Th17 cell differentiation, and attenuate the level of the Th17 cell lineage, contributing to the balance of the Th17/Treg ratio. CONCLUSION: The activation of the Notch signaling pathway can regulate Th17 and Treg cell differentiation, disrupt the CD4+/CD8+ and Th17/Treg balance, and aggravate the severity of EAU; inactivation of the Notch signaling pathway contributes to the CD4+/CD8+ and Th17/Treg balance in EAU rats. Our findings highlighted that the dynamic change in the CD4+/CD8+ and Th17/Treg ratio was consistent with the expression trend of Notch signaling in EAU rats, suggesting that Notch signaling may be a potentially important therapeutic target in clinical practice.