Adiponectin and related C1q/TNF-related proteins bind selectively to anionic phospholipids and sphingolipids.

Adiponectin (Acrp30) is an adipokine associated with protection from cardiovascular disease, insulin resistance, and inflammation. Although its effects are conventionally attributed to binding Adipor1/2 and T-cadherin, its abundance in circulation, role in ceramide metabolism, and homology to C1q suggest an overlooked role as a lipid-binding protein, possibly generalizable to other C1q/TNF-related proteins (CTRPs) and C1q family members. To investigate this, adiponectin, representative family members, and variants were expressed in Expi293 cells and tested for binding to lipids in liposomes using density centrifugation. Binding to physiological lipids were also analyzed using gradient ultracentrifugation, liquid chromatography-mass spectrometry, and shotgun lipidomics. Interestingly, adiponectin selectively bound several anionic phospholipids and sphingolipids, including phosphatidylserine, ceramide-1-phosphate, glucosylceramide, and sulfatide, via the C1q domain in an oligomerization-dependent fashion. Binding to lipids was observed in liposomes, low-density lipoproteins, cell membranes, and plasma. Other CTRPs and C1q family members (Cbln1, CTRP1, CTRP5, and CTRP13) also bound similar lipids. These findings suggest that adiponectin and CTRPs function not only as hormones, but also as lipid opsonins, as may other C1q family proteins.

Giant Cell Arteritis Presenting With Multiple Cranial Neuropathies - Case Report.

Background: Vision loss accounts for most ophthalmic presentations of giant cell arteritis (GCA), but an important minority of patients present with diplopia and other cranial neuropathies. Case study: Here we present the case of an 84-year-old woman with a prior history of multiple cancers who was admitted to our hospital after developing double vision. She was found to have mydriasis, ptosis, and ophthalmoplegia in the right eye (OD) consistent with a combined R CNIII/CNVI neuropathy, as well as highly elevated inflammatory markers. Given her cancer history, the patient was initially worked up for various neoplastic, paraneoplastic, inflammatory, and infectious causes of multiple cranial neuropathies; however, as these results were negative, GCA became a more likely contender as a possible rare cause of multiple cranial neuropathies. The patient underwent temporal artery biopsy which showed pathology consistent with giant cell arteritis, and she was treated with steroids with eventual improvement in ophthalmoplegia and ptosis. Conclusions: This case illustrates the importance of recognizing GCA as a rare possible cause of multiple cranial neuropathies, including the indispensable role of temporal artery biopsy.

Regulation of human Th9 differentiation by type I interferons and IL-21.

Interleukin (IL)-9-producing CD4(+) T cells are a novel subset of T helper (Th) cells that develops independently of the Th1, Th2, Th17 and regulatory T-cell lineages. Similar to the murine model, transforming growth factor (TGF)-beta and IL-4 directed human naive CD4(+) T cells to produce IL-9. Whereas IL-4 suppressed TGF-beta-induced Foxp3 expression, TGF-beta failed to inhibit IL-4-mediated upregulation of the Th2 transcription factor GATA-3. Addition of IL-1 beta, IL-6, IL-10, interferon (IFN)-alpha, IFN-beta or IL-21 to Th9-polarizing conditions augmented Th9 differentiation, while the Th1-associated cytokines IFN-gamma and IL-27 partially suppressed IL-9 production. Given that T cells are a primary source of IL-21, IL-21 expression was analyzed under Th9-polarizing conditions in the context of inflammatory cytokines. Surprisingly, type I IFNs induced elevated levels of IL-21, and blockade of IL-21 abrogated their ability to enhance Th9 differentiation. Taken together, these data indicate a complex cytokine network in the regulation of human IL-9-producing CD4(+) T cells.