SIRT4 Protects Retina Against Excitotoxic Injury by Promoting OPA1-Mediated Müller Glial Cell Mitochondrial Fusion and GLAST Expression.

Purpose: This study aimed to investigate the role of SIRT4 in retinal protection, specifically its ability to mitigate excitotoxic damage to Müller glial cells through the regulation of mitochondrial dynamics and glutamate transporters (GLASTs).

Methods: A model of retinal excitatory neurotoxicity was established in mice. Proteins related to mitochondrial dynamics, GLAST, and SIRT4 were analyzed on days 0, 1, 3, and 5 following toxic injury.

Rapamycin protects glucocorticoid-induced glaucoma model mice against trabecular meshwork fibrosis by suppressing mTORC1/2 signaling.

Systemic or local use of glucocorticoids (GCs) can induce pathological elevation of intraocular pressure (IOP), potentially leading to permanent visual loss. Previous studies have demonstrated that rapamycin (Rapa) inhibits the activation of retinal glial cells (RGC) and the production of neuroinflammation, achieving neuroprotective goals. However, there has been little research on the effect of Rapa on the trabecular meshwork (TM).

SIRT4 Protects Müller Glial Cells Against Apoptosis by Mediating Mitochondrial Dynamics and Oxidative Stress.

SIRT4 is a member of the sirtuin family, which is related to mitochondrial function and possesses antioxidant and regulatory redox effects. Currently, the roles of SIRT4 in retinal Müller glial cells, oxidative stress, and mitochondrial function are still unclear. We confirmed, by immunofluorescence staining, that SIRT4 is located mainly in the mitochondria of retinal Müller glial cells.

CD38 Deficiency Protects Mouse Retinal Ganglion Cells Through Activating the NAD+/Sirt1 Pathway in Ischemia-Reperfusion and Optic Nerve Crush Models.

Purpose: The purpose of this study was to investigate the protective effect of CD38 deletion on retinal ganglion cells (RGCs) in a mouse retinal ischemia/reperfusion (I/R) model and an optic nerve crush (ONC) model, and to elucidate the underlying molecular mechanisms.

Methods: Retinal I/R and ONC models were constructed in mice. PCR was used to identify the deletion of CD38 gene in mice, hematoxylin and eosin (H&E) staining was used to evaluate the changes in retinal morphology, and electroretinogram (ERG) was used to evaluate the changes in retinal function.

Noninvasive Light Flicker Stimulation Promotes Optic Nerve Regeneration by Activating Microglia and Enhancing Neural Plasticity in Zebrafish.

Purpose: Forty-hertz light flicker stimulation has been proven to reduce neurodegeneration, but its effect on optic nerve regeneration is unclear. This study explores the effect of 40-Hz light flicker in promoting optic nerve regeneration in zebrafish and investigates the underlying mechanisms.

Methods: Wild-type and mpeg1:EGFP zebrafish were used to establish a model of optic nerve crush.

Resveratrol Alleviates Retinal Ischemia-Reperfusion Injury by Inhibiting the NLRP3/Gasdermin D/Caspase-1/Interleukin-1β Pyroptosis Pathway.

Purpose: The purpose of this study is to investigate the anti-pyroptotic effect of resveratrol in the context of ischemia-reperfusion (I/R)-induced retinal injury, with a particular focus on Müller glial cells (MGCs) and to elucidate the underlying molecular mechanisms.

Methods: The retinal I/R model was constructed in mice and pyroptotic markers were measured at six, 12, 24, 48, and 72 hours after I/R injury to determine the peak of pyroptotic activity. The effects of resveratrol on pyroptosis, inflammasomes, and the activation of MGCs after I/R injury were observed on the retina of mice.

A pedigree with retinitis pigmentosa and its concomitant ophthalmic diseases.

Aim: To characterize the ophthalmic clinical phenotype of a family with retinitis pigmentosa (RP) and closed-angle glaucoma and to detect pathogenic genes and mutation sites causing RP in this family.

Methods: Ophthalmic clinic performance was examined in detail in 8 enrolled family members. Genomic DNA was extracted from the peripheral blood of 4 family members for whole-exome sequencing (WES) to select potential genetic mutations whose structures were identified by bioinformatics analysis.

Rapamycin suppresses neuroinflammation and protects retinal ganglion cell loss after optic nerve crush.

Pyroptosis, an inflammasome-mediated mode of death, plays an important role in glaucoma. It has been shown that regulating the mTOR pathway can inhibit pyroptosis. Unfortunately, whether rapamycin (RAPA), a specific inhibitor of the mTOR pathway, can inhibit optic nerve crush (ONC)-induced pyroptosis to protect retinal ganglion cells (RGCs) has not been investigated.

Role of the PGE2 receptor in ischemia-reperfusion injury of the rat retina.

Purpose: To investigate the function and expression of the PGE2 receptors EP1-4 in rat retinal ischemia-reperfusion (I/R) injury and to determine the regulatory role of resveratrol (RES) in this process.

Methods: In vitro, we stimulated primary astrocytes extracted from the optic disc of rats with epidermal growth factor (EGF) and RES, and detected the location of EP1-4 expression with immunofluorescence. The expression of antiglial fibrillary acidic protein (GFAP), EGF receptor (EGFR), inducible NOS (iNOS), and EP1-4 in astrocytes was detected with western blotting.

Resveratrol Delays Retinal Ganglion Cell Loss and Attenuates Gliosis-Related Inflammation From Ischemia-Reperfusion Injury.

Purpose: Resveratrol has been shown to enhance the survival of retinal ganglion cells (RGCs) following ischemia-reperfusion (I/R) injury for glaucoma. However, the precise mechanisms for resveratrol's protective effects are still unclear. The aim of this study is to determine whether resveratrol can inhibit RGC apoptosis, retinal gliosis, and inflammation, all of which are critical events in retinal degeneration following I/R injury.

Expression of Sirtuins in the Retinal Neurons of Mice, Rats, and Humans.

Sirtuins are a class of histone deacetylases (HDACs) that have been shown to regulate a range of pathophysiological processes such as cellular aging, inflammation, metabolism, and cell proliferation. There are seven mammalian Sirtuins (SIRT1-7) that play important roles in stress response, aging, and neurodegenerative diseases. However, the location and function of Sirtuins in neurons are not well defined.

FkbN and Tcs7 are pathway-specific regulators of the FK506 biosynthetic gene cluster in Streptomyces tsukubaensis L19.

FK506 (tacrolimus), which is produced by many Streptomyces strains, is clinically used as an immunosuppressive agent and for treatment of inflammatory skin diseases. Here, we identified that the FK506 biosynthetic gene cluster in an industrial FK506-producing strain Streptomyces tsukubaensis L19 is organized as eight transcription units. Two pathway-specific regulators, FkbN and Tcs7, involved in FK506 biosynthesis from S.

Functions of Type II Thioesterases in Bacterial Polyketide Biosynthesis.

Many polyketides show biological activities and have thus been applied in clinics, as food additives, and in agriculture. Type II thioesterases (TEIIs) play an important role in polyketide biosynthesis. Most TEIIs belong to α/β-hydrolase family and usually contain a catalytic triad Ser-His-Asp.

Characterization of Discrete Phosphopantetheinyl Transferases in Streptomyces tsukubaensis L19 Unveils a Complicate Phosphopantetheinylation Network.

Phosphopantetheinyl transferases (PPTases) play essential roles in both primary metabolisms and secondary metabolisms via post-translational modification of acyl carrier proteins (ACPs) and peptidyl carrier proteins (PCPs). In this study, an industrial FK506 producing strain Streptomyces tsukubaensis L19, together with Streptomyces avermitilis, was identified to contain the highest number (five) of discrete PPTases known among any species thus far examined. Characterization of the five PPTases in S.

The substrate promiscuity of a phosphopantetheinyl transferase SchPPT for coenzyme A derivatives and acyl carrier proteins.

Phosphopantetheinyl transferases (PPTases) catalyze the posttranslational modification of acyl carrier proteins (ACPs) in fatty acid synthases (FASs), ACPs in polyketide synthases, and peptidyl carrier proteins (PCPs) in nonribosomal peptide synthetases (NRPSs) in all organisms. Some bacterial PPTases have broad substrate specificities for ACPs/PCPs and/or coenzyme A (CoA)/CoA analogs, facilitating their application in metabolite production in hosts and/or labeling of ACPs/PCPs, respectively. Here, a group II PPTase SchPPT from Streptomyces chattanoogensis L10 was characterized to accept a heterologous ACP and acetyl-CoA.

An acyltransferase domain of FK506 polyketide synthase recognizing both an acyl carrier protein and coenzyme A as acyl donors to transfer allylmalonyl and ethylmalonyl units.

Unlabelled: Acyltransferase (AT) domains of polyketide synthases (PKSs) usually use coenzyme A (CoA) as an acyl donor to transfer common acyl units to acyl carrier protein (ACP) domains, initiating incorporation of acyl units into polyketides. Two clinical immunosuppressive agents, FK506 and FK520, are biosynthesized by the same PKSs in several Streptomyces strains. In this study, characterization of AT4FkbB (the AT domain of the fourth module of FK506 PKS) in transacylation reactions showed that AT4FkbB recognizes both an ACP domain (ACPT csA) and CoA as acyl donors for transfer of a unique allylmalonyl (AM) unit to an acyl acceptor ACP domain (ACP4FkbB), resulting in FK506 production.