Cultured cell models are an essential complement to dissecting kidney proximal tubule (PT) function in health and disease but do not fully recapitulate key features of this nephron segment. We recently determined that culture of opossum kidney (OK) cells under continuous orbital shear stress (OSS) significantly augments their morphological and functional resemblance to PTs in vivo. Here we used RNASeq to identify temporal transcriptional changes upon cell culture under static or shear stress conditions. Comparison of gene expression in cells cultured under static or OSS conditions with a database of rat nephron segment gene expression confirms that OK cells cultured under OSS are more similar to the PT in vivo compared with cells maintained under static conditions. Both improved oxygenation and mechanosensitive stimuli contribute to the enhanced differentiation in these cells, and we identified temporal changes in gene expression of known mechanosensitive targets. We observed changes in mRNA and protein levels of membrane trafficking components that may contribute to the enhanced endocytic capacity of cells cultured under OSS. Our data reveal pathways that may be critical for PT differentiation in vivo and validate the utility of this improved cell culture model as a tool to study PT function.Cotton rats are one of the experimental rodents used for testing different infectious and non-infectious diseases, including gastrointestinal tract pathology. However, their intestinal morphological characteristics are still poorly understood. Here, we clarified the anatomical and histological characteristics of the cecum and ascending colon (AC) of young (1-3-month old), adult (4-6-month old), and old (10-12-month old) cotton rats. The large intestine (LI) in cotton rats is composed of the cecum, AC, transverse and descending colons, and rectum, and is similar to that of other mammals. The AC begins with a double or triple spiral loop-like flexure (SLLF) and ends with a coupled horseshoe-like flexure (HSLF). A single longitudinal mucosal fold (SLMF) was found at the beginning of the AC along the mesentery line and developed with age. Furthermore, the SLMF contained several lymphatic nodules (LNs), indicating their role in digestive and immunological functions. Small and large protuberant LNs were found in the cecum and SLLF, respectively, whereas thin and flat LNs were observed in the HSLF and transverse colon, respectively. Regarding sex-related differences, adult females had a significantly longer AC with a higher number of SLLFs compared to males. The SLMF length and LN number were also longer and higher, respectively, in adult females compared to adult males. These are crucial findings, indicating the presence of sex-related differences in the morphology of the LI in cotton rats, and ours is the first study to discover a sex difference in the mammalian LI lining. Our study clarified the unique morphology of the LI in cotton rats, which could serve as the principal model for elucidating species-specific digestive tract functions and gastrointestinal disorders.The role of Cl- as an intracellular signaling ion has been increasingly recognized in recent years. One of the currently best described roles of Cl- in signaling is the modulation of the With-No-Lysine (K) (WNK) - STE20-Proline Alanine rich Kinase (SPAK)/Oxidative Stress Responsive Kinase 1 (OSR1) - Cation-Coupled Cl- Cotransporters (CCCs) cascade. Binding of a Cl- anion to the active site of WNK kinases directly modulates their activity, promoting their inhibition. WNK activation due to Cl- release from the binding site leads to phosphorylation and activation of SPAK/OSR1, which in turn phosphorylate the CCCs. Phosphorylation by WNKs-SPAK/OSR1 of the Na+-driven CCCs (mediating ions influx) promote their activation, whereas that of the K+-driven CCCs (mediating ions efflux) promote their inhibition. This results in net Cl- influx and feedback inhibition of WNK kinases. A wide variety of alterations to this pathway have been recognized as the cause of several human diseases, with manifestations in different systems. The understanding of WNK kinases as Cl- sensitive proteins has allowed us to better understand the mechanistic details of regulatory processes involved in diverse physiological phenomena that are reviewed here. These include cell volume regulation, potassium sensing and intracellular signaling in the renal distal convoluted tubule, and regulation of the neuronal response to the neurotransmitter GABA.The red imported fire ant, Solenopsis invicta, is a eusocial invasive insect that has spread worldwide. Chemosensory proteins (CSPs) are ligand-binding proteins that participate in a diverse range of physiological processes that include olfaction and chemical transport. Here, we performed a systematic survey of the expression of the 21 gene S. invicta CSP family that includes at least two groups of apparent S. invicta-specific gene expansions. These data revealed caste, tissue, and developmental stage-specific differential expression of the SiCSPs. In general, moderate to high SiCSP expression was seen in worker antennae and abdomen tissues with lower expression in head/thorax regions. Male and female alates showed high antennal expression of fewer SiCSPs, with the female alate thorax showing comparatively high SiCSP expression. SiCSP expression was lower in male alates tissues compared to workers and female alates, albeit with some highly expressed SiCSPs. SiCSP expression was low during development including in eggs, larvae (early and late instars), and pupae. Global analyses revealed examples of conserved, divergent, and convergent SiCSP expression patterns linked to phylogenetic relationships. Sodium Monensin order The developmental and caste-specific variation seen in SiCSP expression patterns suggests specific functional diversification of CSPs that may translate into differential chemical recognition and communication among individuals and/or reflect other cellular roles of CSPs. Our results support a model for CSPs acting as general ligand carriers involved in a wide range of physiological processes beyond olfaction. As compared to the expression patterns of the S. invicta odorant binding proteins (OBPs), an inverse correlation between SiOBP and SiCSP expression was seen, suggesting potential complementary and/or compensatory functions between these two classes of ligand carriers.