Search

Objective— Human genetic variants near the FADS (fatty acid desaturase) gene cluster ( FADS1-2 - 3 ) are strongly associated with cardiometabolic traits including dyslipidemia, fatty liver, type 2 diabetes mellitus, and coronary artery disease. However, mechanisms underlying these genetic associations are unclear. Approach and Results— Here, we specifically investigated the physiological role of the Δ-5 desaturase FADS1 in regulating diet-induced cardiometabolic phenotypes by treating hyperlipidemic LDLR (low-density lipoprotein receptor)-null mice with antisense oligonucleotides targeting the selective knockdown of Fads1 . Fads1 knockdown resulted in striking reorganization of both ω-6 and ω-3 polyunsaturated fatty acid levels and their associated proinflammatory and proresolving lipid mediators in a highly diet-specific manner. Loss of Fads1 activity promoted hepatic inflammation and atherosclerosis, yet was associated with suppression of hepatic lipogenesis. Fads1 knockdown in isolated macrophages promoted classic M1 activation, whereas suppressing alternative M2 activation programs, and also altered systemic and tissue inflammatory responses in vivo. Finally, the ability of Fads1 to reciprocally regulate lipogenesis and inflammation may rely in part on its role as an effector of liver X receptor signaling. Conclusions— These results position Fads1 as an underappreciated regulator of inflammation initiation and resolution, and suggest that endogenously synthesized arachidonic acid and eicosapentaenoic acid are key determinates of inflammatory disease progression and liver X receptor signaling.

To show PR damage as the location of visually significant pathological changes in MEWDS with the use of multimodal imaging., Purpose: To elucidate the location of pathological changes in multiple evanescent white dot syndrome (MEWDS) with the use of multimodal adaptive optics (AO) imaging. Methods: A 5-year observational case study of a 24-year-old female with recurrent MEWDS. Full examination included history, Snellen chart visual acuity, pupil assessment, intraocular pressures, slit lamp evaluation, dilated fundoscopic exam, imaging with Fourier-domain optical coherence tomography (FD-OCT), blue-light fundus autofluorescence (FAF), fundus photography, fluorescein angiography, and adaptive-optics optical coherence tomography. Results: Three distinct acute episodes of MEWDS occurred during the period of follow-up. Fourier-domain optical coherence tomography and adaptive-optics imaging showed disturbance in the photoreceptor outer segments (PR OS) in the posterior pole with each flare. The degree of disturbance at the photoreceptor level corresponded to size and extent of the visual field changes. All findings were transient with delineation of the photoreceptor recovery from the outer edges of the lesion inward. Hyperautofluorescence was seen during acute flares. Increase in choroidal thickness did occur with each active flare but resolved. Conclusion: Although changes in the choroid and RPE can be observed in MEWDS, Fourier-domain optical coherence tomography, and multimodal adaptive optics imaging localized the visually significant changes seen in this disease at the level of the photoreceptors. These transient retinal changes specifically occur at the level of the inner segment ellipsoid and OS/RPE line. En face optical coherence tomography imaging provides a detailed, yet noninvasive method for following the convalescence of MEWDS and provides insight into the structural and functional relationship of this transient inflammatory retinal disease.

Studies suggest that dietary enrichment of polyunsaturated fatty acids (PUFAs) may improve CVD outcomes, however the mechanisms underlying these observations remain elusive. Additionally, genome-wide association studies have linked single nucleotide polymorphisms (SNPs) in genes encoding essential PUFA metabolizing enzymes, the Fatty Acid Desaturases 1, 2, and 3 ( FADS1-2-3 ), to dyslipidemia and other metabolic risk factors known to be linked to CVD. Since enzymatic oxidation of specific PUFAs, commonly arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), generate signaling mediators that coordinate both the initiation and resolution of inflammation, understanding the interplay of PUFA metabolism and vascular inflammation has broad implications in cardiometabolic drug discovery. Here we have altered the abundances of distinct dietary and endogenously-synthesized PUFAs, and associated lipid mediators, in hyperlipidemic Ldlr-/- mice to understand the signaling mechanisms underlying the PUFA-CVD link. We diversified PUFA profiles by feeding diets enriched in either ω-6 or ω-3 PUFAs, and inhibited endogenous production of AA and EPA by antisense oligonucleotide (ASO)-mediated knockdown of the Δ5 desaturase Fads1. Fads1 knockdown results in accumulation of its substrate fatty acids (dihomo-γ-linolenic acid and eicosatrienoic acid) and marked reduction in its enzymatic products (AA and EPA). Metabololipidomic profiling reveals that Fads1 knockdown alters select AA-, EPA-, and DHA-derived lipid mediators in a diet-specific manner. Interestingly, Fads1 knockdown protects Ldlr-/- mice from obesity and insulin resistance regardless of diet, yet alters increases circulating monocyte subsets and promotes dyslipidemia in a highly diet-specific manner. How these phenotypes link to diet-induced atherosclerosis burden in Fads1 knockdown mice will also be presented. Collectively, our studies provide new information in regards to the relative contribution of endogenous (FADS1-derived) and exogenous (diet-derived) AA and EPA in driving cardiometabolic phenotypes. Furthermore, our studies provide the first mechanistic understanding behind the genetic link of FADS1-2-3 SNPs and atherosclerosis.

The gut microbiome represents an important endocrine organ generating nutrient metabolites that promote the pathogenesis of cardiovascular disease (CVD), as exemplified by the gut microbe-derived metabolite trimethylamine-N-oxide (TMAO). The meta-organismal TMAO pathway is initiated by ingestion of nutrients present in high fat foods (phosphatidylcholine, choline, and L -carnitine), which are metabolized by gut microbes to generate trimethylamine (TMA). The gut microbial metabolite TMA is further metabolized by the host enzyme flavin monooxygenase 3 (FMO3) to produce TMAO, which signals to drive proatherogenic programs in the host. Our previous work has demonstrated that the TMAO-producing enzyme FMO3 is a central regulator of whole body cholesterol balance and reverse cholesterol transport (RCT). However, the ability of FMO3 to regulate cholesterol balance and RCT is largely dependent on the amount of dietary cholesterol available. Given that the meta-organismal TMAO pathway is highly dependent on dietary cues, we hypothesized that the host enzyme FMO3 may be a central integrator of both choline- and cholesterol-driven atherosclerosis. To determine the role of FMO3 in diet-driven atherosclerosis progression, female hyperlipidemic LDLr -/- mice received either control or FMO3 antisense oligonucleotides (ASO) while being fed a basal control diet or proatherogenic diets containing 1) 0.2% cholesterol, 2) 1.2% choline, or 3) both 0.2% cholesterol and 1.2% choline for 16 weeks. FMO3 knockdown markedly reduced plasma cholesterol under all dietary conditions, yet only reduced plasma triglycerides in the choline-supplemented mice. Unexpectedly, FMO3 knockdown also elevated circulating monocytes and altered T cell subsets in a diet-specific manner, indicating a role for FMO3 in immune cell maturation only when certain nutrients are available in the diet. The relationship to these diet- and FMO3-dependent CVD risk factors to total atherosclerosis lesion area and lesion-associated immune cell burden will also be presented. Collectively, our studies suggest that host enzyme FMO3 plays a central role in integrating dietary cues (choline & cholesterol) to lipid metabolic and immune cell reprogramming that synergize to promote atherosclerosis.

Previous publications from our laboratory show that cholesterol-fed LDLr-/-, apoA-I -/- (DKO) mice develop accelerated atherosclerosis, as well as, a severe autoimmune disorder not seen in diet-fed LDLr -/- mice (SKO). This phenotype is characterized by the expansion of cholesterol loaded T cells within lymphoid organs such as skin draining lymph nodes and spleen as well as the manifestation of aberrant T cell responses. In order to examine the link between the progression of atherosclerosis and the onset of autoimmunity we examined the type and amount of immune cell infiltration in both the aorta and the skin of DKO and SKO mice fed an atherogenic diet for 12 weeks. In a subset of mice the immunomodulator, Fingolimod (FTY720), a sphingosine analogue was administered along with the diet. After 12 weeks, plaque burden in the aortic root was measured as both neutral lipid accumulation, and as the type and number of immune cells present. As expected, diet alone increased both lipid and immune cell infiltration in the aortic root, as well as in the skin of DKO compared to SKO mice. Interestingly, FTY-diet DKO mice showed a sharp reduction in both lipid accumulation as well as CD4+ cell infiltration in the aortic root. This decrease in aortic lipid deposition in FTY-diet DKO was well below that of any of the other groups, including diet-only SKO mice, while FTY-diet SKO were not different than diet-only SKO mice. These data suggest that heightened aortic inflammation observed in response to dietary cholesterol in the absence of apoA-I, renders the DKO aorta more susceptible to the immunomodulatory effects of FTY. Quite unexpectedly, the skin of FTY-diet DKO mice continued to show massive cholesterol accumulation and inflammation with a preservation of subcutaneous fat, in light of the dramatic reduction in aortic infiltrates observed. When DKO mice lacking T and B cells (Rag1-/-, LDLr-/-, apoA-I-/-) were studied, massive skin cholesterol accumulation was still observed and TKO mouse dermis showed infiltrates largely composed of neutrophils and monocytes, suggesting that dermal cholesterol imbalance, in the absence of apoA-I, was the basis for disease initiation in the skin. Overall, these studies illustrate the vastly different roles of apoA-I and immunomodulatory drugs in skin versus aorta cholesterol balance.

We report a case of urethral malacoplakia associated with disease of the bladder and bladder neck. Treatment consisted of fulguration of the bladder lesions and excision of the urethral lesion. Unlike most other cases of genitourinary malacoplakia, which are associated with chronic urinary tract infection, this patient had sterile urine and no history of urinary tract infections. Urethral malacoplakia is reviewed, and the pathogenesis and treatment of the disease are discussed.