Characterization of miR-335-5p and miR-335-3p in human osteoarthritic tissues.

OBJECTIVE: We aimed to characterize the expression patterns, gene targets, and functional effects of miR-335-5p and miR-335-3p among seven primary human knee and hip osteoarthritic tissue types. METHODS: We collected synovial fluid, subchondral bone, articular cartilage, synovium, meniscus/labrum, infrapatellar/acetabular fat, anterior cruciate ligament/ligamentum teres, and vastus medialis oblique/quadratus femoris muscle (n = 7-20) from surgical patients with early- or late-stage osteoarthritis (OA) and quantified miR-335-5p and miR-335-3p expression by real-time PCR. Predicted gene targets were measured in knee OA infrapatellar fat following miRNA inhibitor transfection (n = 3), and prioritized gene targets were validated following miRNA inhibitor and mimic transfection (n = 6). Following pathway analyses, we performed Oil-Red-O staining to assess changes in total lipid content in infrapatellar fat. RESULTS: Showing a 227-fold increase in knee OA infrapatellar fat (the highest expressing tissue) versus meniscus (the lowest expressing tissue), miR-335-5p was more abundant than miR-335-3p (92-fold increase). MiR-335-5p showed higher expression across knee tissues versus hip tissues, and in late-stage versus early-stage knee OA fat. Exploring candidate genes, VCAM1 and MMP13 were identified as putative direct targets of miR-335-5p and miR-335-3p, respectively, showing downregulation with miRNA mimic transfection. Exploring candidate pathways, predicted miR-335-5p gene targets were enriched in a canonical adipogenesis network (p = 2.1e - 5). Modulation of miR-335-5p in late-stage knee OA fat showed an inverse relationship to total lipid content. CONCLUSION: Our data suggest both miR-335-5p and miR-335-3p regulate gene targets in late-stage knee OA infrapatellar fat, though miR-335-5p appears to be more prominent, with tissue-, joint-, and stage-specific effects.

Can genetics guide exercise prescriptions in osteoarthritis?

Osteoarthritis (OA) is the most common form of arthritis and has a multifactorial etiology. Current management for OA focuses on minimizing pain and functional loss, typically involving pharmacological, physical, psychosocial, and mind-body interventions. However, there remain challenges in determining which patients will benefit most from which interventions. Although exercise-based interventions are recommended as first-line treatments and are known to be beneficial for managing both the disease and illness of OA, the optimal exercise "prescription" is unknown, due in part to our limited understanding of the precise mechanisms underlying its action. Here we present our perspective on the potential role of genetics in guiding exercise prescription for persons with OA. We describe key publications in the areas of exercise and OA, genetics and OA, and exercise and genetics, and point to a paucity of knowledge at the intersection of exercise, genetics, and OA. We suggest there is emerging evidence to support the use of genetics and epigenetics to explain the beneficial effects of exercise for OA. We identify missing links in the existing research relating to exercise, genetics, and OA, and highlight epigenetics as a promising mechanism through which environmental exposures such as exercise may impact OA outcomes. We anticipate future studies will improve our understanding of how genetic and epigenetic factors mediate exercise-based interventions to support implementation and ultimately improve OA patient care.

NLRP3 inflammasome in rosmarinic acid-afforded attenuation of acute kidney injury in mice.

Cisplatin (CP) is a well-known anticancer drug used to effectively treat various kinds of solid tumors. CP causes acute kidney injury (AKI) and unfortunately, there is no therapeutic approach in hand to prevent AKI. Several signaling pathways are responsible for inducing AKI which leads to inflammation in proximal convoluted tubule cells in the kidney. Furthermore, the nucleotide-binding oligomerization domain (NOD)-like receptor containing pyrin domain 3 (NLRP3) inflammasome is involved in the CP-induced AKI. In this study, we investigated therapeutic effects of rosmarinic acid (RA) against inflammation-induced AKI. RA was orally administered at the dose of 100 mg/kg for two consecutive days after 24 h of a single injection of CP at the dose of 20 mg/kg administered intraperitoneally in Swiss albino male mice. Treatment of RA inhibited the activation of NLRP3 signaling pathway by blocking the activated caspase-1 and downstream signal molecules such as IL-1ß and IL18. CP activated HMGB1-TLR4/MyD88 axis was also found to be downregulated with the RA treatment. Activation of nuclear factor-κB and elevated protein expression of cyclooxygenase-2 (COX-2) were also found to be downregulated in RA-treated animals. Alteration of early tubular injury biomarker, kidney injury molecule-1 (KIM-1), was found to be subsided in RA-treated mice. RA has been earlier reported for antioxidant and anti-inflammatory properties. Our findings show that blocking a critical step of inflammasome signaling pathway by RA treatment can be a novel and beneficial approach to prevent the CP-induced AKI.

Halictine-2 antimicrobial peptide shows promising anti-parasitic activity against Leishmania spp.

The protozoan parasite Leishmania spp. causes leishmaniases, a group of diseases creating serious health problems in many parts of the world with significant resistance to existing drugs. Insect derived antimicrobial peptides are promising alternatives to conventional drugs against several human disease-causing pathogens because they do not generate resistance. Halictine-2, a novel antimicrobial peptide from the venom of eusocial honeybee, Halictus sexcinctus showed significant anti-leishmanial activity in vitro, towards two life forms of the dimorphic parasite, the free-swimming infective metacyclic promastigotes and the intracellular amastigotes responsible for the systemic infection. The anti-leishmanial activity of the native peptide (P5S) was significantly enhanced by serine to threonine substitution at position 5 (P5T). The peptide showed a propensity to form α-helices after substitution at position-5, conferring amphipathicity. Distinct pores observed on the promastigote membrane after P5T exposure suggested a mechanism of disruption of cellular integrity. Biochemical alterations in the promastigotes after P5T exposure included generation of increased oxygen radicals with mitochondrial Ca2+ release, loss of mitochondrial membrane potential, reduction in total ATP content and increased mitochondrial mass, resulting in quick bioenergetic and chemiosmotic collapse leading to cell death characterized by DNA fragmentation. P5T was able to reduce intracellular amastigote burden in an in vitro model of Leishmania infection but did not alter the proinflammatory cytokines like TNF-α and IL-6. The ability of the P5T peptide to kill the Leishmania parasite with negligible haemolytic activity towards mouse macrophages and human erythrocytes respectively, demonstrates its potential to be considered as a future antileishmanial drug candidate.

Genome-wide identification and biochemical characterization of calcineurin B-like calcium sensor proteins in Chlamydomonas reinhardtii.

Calcium (Ca2+) signaling is involved in the regulation of diverse biological functions through association with several proteins that enable them to respond to abiotic and biotic stresses. Though Ca2+-dependent signaling has been implicated in the regulation of several physiological processes in Chlamydomonas reinhardtii, Ca2+ sensor proteins are not characterized completely. C. reinhardtii has diverged from land plants lineage, but shares many common genes with animals, particularly those encoding proteins of the eukaryotic flagellum (or cilium) along with the basal body. Calcineurin, a Ca2+/calmodulin-dependent protein phosphatase, is an important effector of Ca2+ signaling in animals, while calcineurin B-like proteins (CBLs) play an important role in Ca2+ sensing and signaling in plants. The present study led to the identification of 13 novel CBL-like Ca2+ sensors in C. reinhardtii genome. One of the archetypical genes of the newly identified candidate, CrCBL-like1 was characterized. The ability of CrCBL-like1 protein to sense as well as bind Ca2+ were validated using two-step Ca2+-binding kinetics. The CrCBL-like1 protein localized around the plasma membrane, basal bodies and in flagella, and interacted with voltage-gated Ca2+ channel protein present abundantly in the flagella, indicating its involvement in the regulation of the Ca2+ concentration for flagellar movement. The CrCBL-like1 transcript and protein expression were also found to respond to abiotic stresses, suggesting its involvement in diverse physiological processes. Thus, the present study identifies novel Ca2+ sensors and sheds light on key players involved in Ca2+signaling in C. reinhardtii, which could further be extrapolated to understand the evolution of Ca2+ mediated signaling in other eukaryotes.