Objective: Single-cell RNA sequencing (scRNA-seq) analyses have provided a novel insight into cell-specific gene expression changes in diseases. Here, this study was conducted to identify cell types and pathophysiologic factors in diabetic nephropathy. Methods: Single-cell RNA sequencing data of three human diabetic kidney specimens and three controls were retrieved from the GSE131882 dataset. Following preprocessing and normalization, cell clustering was presented and cell types were identified. Marker genes of each cell type were identified by comparing with other cell types. A ligand-receptor network analysis of immune cells was then conducted. Differentially expressed marker genes of immune cells were screened between diabetic nephropathy tissues and controls and their biological functions were analyzed. Diabetic nephropathy rat models were established and key marker genes were validated by RT-qPCR and Western blot. Results: Here, 10 cell types were clustered, including tubular cells, endothelium, parietal epithelial cells, podocytes, collecting duct, mesangial cells, immune cells, distal convoluted tubule, the thick ascending limb, and proximal tubule in the diabetic kidney specimens and controls. Among them, immune cells had the highest proportion in diabetic nephropathy. Immune cells had close interactions with other cells by receptor-ligand interactions. Differentially expressed marker genes of immune cells EIF4B, RICTOR, and PRKCB were significantly enriched in the mTOR pathway, which were confirmed to be up-regulated in diabetic nephropathy. Conclusion: Our findings identified immune cells and their marker genes (EIF4B, RICTOR, and PRKCB) as key pathophysiologic factors that might contribute to diabetic nephropathy progression.

Ciliary neurotrophic factor (CNTF) is well known as a growth/survival factor of neuronal tissue. We investigated the expression of CNTF and its specific receptor alpha (CNTFRα) in a unilateral ureteral obstruction (UUO) model. Complete UUO was produced by left ureteral ligation in Sprague-Dawley rats. The animals were sacrificed on days 1, 3, 5, 7, 14, 21, and 28 after UUO. The kidneys were fixed, and processed for both immunohistochemistry and in situ hybridization. CNTF immunoreactivity in sham-operated kidneys was observed only in the descending thin limb (DTL) of the loop of Henle. In UUO kidneys, CNTF expression was induced in the S3 segment (S3s) of the proximal tubule from day 1, and progressively expanded into the entire S3s and a part of the convoluted proximal tubules, distal tubules (DT), and glomerular parietal epithelium up to day 7. Upregulated CNTF expression was maintained to day 28. From day 14, the inner medullary collecting duct showed weak CNTF immunoreactivity. The CNTFRα mRNA hybridization signal in sham-operated kidneys was weakly detected in the DTL, DT, medullary thick ascending limb, and in a few S3s cells. After UUO, CNTFRα mRNA expression increased progressively in both the renal cortex and the medulla up to day 7 and increased expression was maintained until day 28. The results suggest that the S3s may be the principal induction site for CNTF in response to renal injury, and that CNTF may play a role in chronic renal injury.

To gain molecular insight into kidney function, we performed a high-resolution quantitative analysis of gene expression in glomeruli and nine different nephron segments dissected from mouse kidney using Serial Analysis of Gene Expression (SAGE). We also developed dedicated bioinformatics tools and databases to annotate mRNA tags as transcripts. Over 800,000 mRNA SAGE tags were sequenced corresponding to >20,000 different mRNA tags present at least twice in at least one library. Hierarchical clustering analysis of tags demonstrated similarities between the three anatomical subsegments of the proximal tubule, between the cortical and medullary segments of the thick ascending limb of Henle's loop, and between the three segments constituting the aldosterone-sensitive distal nephron segments, whereas the glomerulus and distal convoluted tubule clusterized independently. We also identified highly specific mRNA markers of each subgroup of nephron segments and of most nephron segments. Tag annotation also identified numbers of putative antisense mRNAs. This database constitutes a reference resource in which the quantitative expression of a given gene can be compared with that of other genes in the same nephron segment, or between different segments of the nephron. To illustrate possible applications of this database, we performed a deeper analysis of the glomerulus transcriptome that unexpectedly revealed expression of several ion and water carriers; within the glomerulus, they were found to be preferentially expressed in the parietal sheet. It also revealed the major role of the zinc finger transcription factor Wt1 in the specificity of gene expression in the glomerulus. Finally, functional annotation of glomerulus-specific transcripts suggested a high proliferation activity of glomerular cells. Immunolabeling for PCNA confirmed a high percentage of proliferating cells in the glomerulus parietal sheet.

Paleoneurology concerns the study and analysis of fossil endocasts. Together with cranial capacity and discrete anatomical features, shape can be analysed to consider the spatial relationships between structures and to investigate the endocranial structural system. A sample of endocasts from fossil specimens of the genus Homo has been analysed using traditional metrics and 2D geometric morphometrics based on lateral projections of endocranial shape. The maximum and frontal widths show a size-related pattern of variation shared by all the taxa considered. Furthermore, as cranial capacity increases in the non-modern morphotypes there is a general endocranial vertical stretching (mainly centred at the anterior ascending circumvolution) with flattening and relative shortening of the parietal areas. This pattern could have involved some structural stress between brain development and vault bones at the parietal midsagittal profile in the heavy encephalised Neandertals. In contrast, modern humans show a species-specific neomorphic hypertrophy of the parietal volumes, leading to a dorsal growth and ventral flexion (convolution) and consequent globularity of the whole structure. Brain tensors such as the falx cerebri have been hypothesised to represent one of the main physical constraints on morphogenetic trajectories, with additional influences from cranial base structures. The neurofunctional inferences discussed here stress the role of the parietal areas in the visuo-spatial coordination and integration, which can be involved in higher cerebral functions and related to conceptual thinking.

Using a polyclonal antibody against authentic thromboxane A2/prostaglandin H2 (TxA2/PGH2) receptor protein, we assessed the distribution of this receptor in the normal rat kidney by routine methods of immunofluorescence microscopy. The receptor localized both in glomeruli and in tubules. In the former, the distribution of the receptor was most prominent along the lumen of glomerular capillary loops. Parietal epithelial cells of the Bowman's capsule, podocytes and mesangial cells also demonstrated immunostainable receptor. In the tubules, the receptor localized most prominently at the base of the brush border of proximal tubules and at the luminal surface of thick ascending limbs and distal convoluted tubules. These observations point to sites that are likely to be targeted by thromboxane A2 in forms of renal injury characterized by enhanced synthesis of this eicosanoid.

The proliferative activity of various normal human renal cell populations is unknown. Recently, antibodies to cell proliferation-associated nuclear proteins, such as proliferating cell nuclear antigen (PCNA) and KI-67, which are applicable to archival paraffin sections, became available. With antibodies to PCNA and Ki-67 after microwave pretreatment of the paraffin sections, the proliferation indexes (ratio of positive nuclei with PCNA and Ki-67 antibodies/all nuclei counted x 100, i.e. percentage of positive cells) of 12 different intrinsic renal cell populations in 20 normal human kidneys have been determined. The following proliferation indexes (percentages of positive cells) were found with the PCNA and the Ki-67 antibodies, respectively: proximal tubular epithelium, 0.22, 0.24; thin limb of Henle, 0.29, 0.30; thick ascending limb of Henle, 0.32, 0.29; distal tubular epithelium (distal convoluted tubules and cortical collecting ducts, 0.33, 0.44; medullary collecting ducts, 0.32, 0.3; glomerular mesangial cells, 0.07, 0.12; glomerular visceral epithelial cells, 0.04, 0.08; glomerular parietal epithelial cells, 0.07, 0.1; glomerular capillary endothelium, 0.42, 0.47; peritubular capillary endothelial cells, 0.38, 0.43; endothelium of large intrarenal vessels (arteries and veins), 0.09, 0.12. Thus, normally capillary endothelium (glomerular and peritubular) appears to have the highest proliferation index in the human kidney by these techniques. These results indicate major variation in the proliferative activity of normal human renal cell populations, along with a significant correlation between PCNA and Ki-67 staining. Furthermore, this study provides normal values for the proliferative activity of different human renal cell populations.(ABSTRACT TRUNCATED AT 250 WORDS)

The antigenic composition of the human corneal endothelium, a cellular layer essential for maintaining corneal function, has not been well characterized. A novel corneal endothelial antigen was identified by generating a monoclonal antibody (MAb) against normal human corneal endothelial cells. This MAb, designated 2B4.14.1, reacted strongly by immunoperoxidase staining with the endothelium of corneas from all human donors tested but not with other corneal components, including epithelium and stroma. Positive immunohistologic reactions of 2B4.14.1 with several other human tissues, including kidney (parietal epithelium of Bowman's capsule, proximal convoluted tubule, ascending limb of Henle's loop, and distal convoluted tubule), glandular epithelia of numerous organs, and mesothelial linings of several thoracic and abdominal viscera, also were observed. One of the renal antigens recognized by 2B4.14.1 was identified as Tamm-Horsfall glycoprotein (THGP), based on the ability of the antibody to recognize THGP in western immunoblots and the abrogation of immunohistologic reactivity of the antibody by preincubation with purified THGP. These findings raise the possibility that the human cornea expresses a molecule with homeostatic properties similar to those ascribed to THGP. However, it is unlikely that the corneal antigen recognized by 2B4.14.1 is conventional THGP; a MAb specific for THGP did not react with corneal endothelium.

Measurements of the total convoluted surface area of cortex buried in the temporoparietal transition of the Sylvian fissure were performed using "three-dimensional" magnetic resonance morphometry in 10 randomly selected human cadaver brains. The measurements comprised the planum temporale, which covers the superior temporal gyrus posterior to Heschl's first transverse gyrus, and the caudally adjacent walls of the descending and ascending rami of the Sylvian fissure. Also, the total convoluted surface of the planum temporale was compared with its superficially exposed surface as determined by photographical planimetry after brain section, so that the index of cortical folding of the planum temporale could be estimated. The following results were obtained: Cortical folding of the planum temporale did not differ significantly between left and right hemispheres (p greater than .6). The total and the superficially exposed surface of the planum temporale showed significant leftward asymmetry (p less than or equal to .0078). In contrast, the total surface of cortex buried in the caudal segments of the Sylvian fissure posterior to the planum exhibited significant rightward asymmetry (p less than or equal to .016). The combined cortical surface area buried in the whole posterior Sylvian fissure caudal to the first transverse gyrus did not show significant left-right asymmetry (p greater than 0.3). The data suggest divergent lateral asymmetries in the posterior intrasylvian region with excesses of superior temporal cortex in left hemispheres and of supramarginal cortex in right hemispheres.