The Effects of Perilla frutescens Extracts on IgA Nephropathy: A Systematic Review and Meta-Analysis

(1) Background: Chronic renal disorders (CRD) are associated with significant comorbidities and necessitate complex therapeutic management. As time passed, Perilla frutescens (PF) became a promising therapeutic option for CRD. The aim of this systematic review and meta-analysis was to outline the therapeutic effects of PF extracts on various models of immunoglobulin a (IgA) nephropathy; (2) Methods: Medline, Embase, and Cochrane databases were used to find relevant studies. All prospective interventional studies that evaluated the effect of PF extract versus placebo on rat models of chronic renal disorders were assessed according to the international guidelines; (3) Results: Our search yielded 23 unique records, out of which only five were included in the analysis. Our results showed that administration of PF extracts led to a statistically significant reduction in proteinuria and PCNA levels in rats that received high doses of the extract as well as in the PCNA level and DNA synthesis in rats that received low doses of the extract. The evaluated outcomes benefited from a low degree of heterogeneity; (4) Conclusions: Some of the evaluated outcomes were significantly reduced by both high and low doses of extracts from Perilla frutescens. Further studies are needed to determine the exact effect over IgA nephropathy in human subjects.

Cold Shock Proteins Mediate GN with Mesangioproliferation

DNA binding protein A (DbpA) is a member of the human cold shock domain-containing protein superfamily, with known functions in cell proliferation, differentiation, and stress responses. DbpA mediates tight junction-associated activities in tubular epithelial cells, but the function of DbpA in mesangial cells is unknown. Here, we found DbpA protein expression restricted to vascular smooth muscle cells in healthy human kidney tissue but profound induction of DbpA protein expression within the glomerular mesangial compartment in mesangioproliferative nephritis. In vitro, depletion or overexpression of DbpA using lentiviral constructs led to inhibition or promotion, respectively, of mesangial cell proliferation. Because platelet-derived growth factor B (PDGF-B) signaling has a pivotal role in mesangial cell proliferation, we examined the regulatory effect of PDGF-B on DbpA. In vitro studies of human and rat mesangial cells confirmed a stimulatory effect of PDGF-B on DbpA transcript numbers and protein levels. Additional in vivo investigations showed DbpA upregulation in experimental rat anti-Thy1.1 nephritis and murine mesangioproliferative nephritis models. To interfere with PDGF-B signaling, we injected nephritic rats with PDGF-B neutralizing aptamers or the MEK/ERK inhibitor U0126. Both interventions markedly decreased DbpA protein expression. Conversely, continuous PDGF-B infusion in healthy rats induced DbpA expression predominantly within the mesangial compartment. Taken together, these results indicate that DbpA is a novel target of PDGF-B signaling and a key mediator of mesangial cell proliferation.

A novel CRIg-targeted complement inhibitor protects cells from complement damage

The inappropriate activation of complement may contribute to various immune diseases. The alternative pathway (AP) predominates during complement activation regardless of the initiating pathways. Hence, the main AP regulator factor H (FH) holds great potential as an attractive therapeutic intervention. In addition, complement receptor of the immunoglobulin superfamily (CRIg) has been demonstrated to inhibit AP and, more notably, still specifically binds to C3b/iC3b. We thus developed novel CRIg-targeted complement inhibitors by connecting the functional domains of CRIg and FH, which we termed CRIg-FH and CRIg-L-FH. CRIg-L-FH, slightly more potent than CRIg-FH, considerably inhibited both AP- and also classical pathway (CP)-mediated hemolysis and successfully eliminated the deposition of C3b/iC3b. Kinetic analysis further revealed that the binding affinity constant (KD) of CRIg/FH was in the micromolar range, consistent with its long-lasting binding to complement-attacked cells. CRIg-L-FH efficiently protected aberrant erythrocytes of patients with paroxysmal nocturnal hemoglobinuria (PNH) from AP- and CP-mediated complement damage (IC50 was 22.43 and 64.69 nM, respectively). Moreover, CRIg-L-FH was found to inhibit complement activation induced by the anti-Thy1 antibody in a mesangioproliferative glomerulonephritis (MPGN) rat model. Hence, CRIg-L-FH protects glomerular mesangial cells (GMCs) from complement-mediated injury and proliferative lesions. These findings strongly suggest that CRIg/FH is a potential therapeutic drug candidate for a range of complement-mediated diseases.

Mesangioproliferative glomerulonephritis in an infant with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a neurobehavioral disorder characterized mainly by neonatal hypotonia, dysmorphic features, hypogonadism, mental retardation and behavioral problems. The PWS has not been associated with renal complications. We report the case of an infant with Prader-Willi syndrome due to loss of the paternal copy of chromosome 15q11.2-13, who presented with severe proteinuria and microscopic hematuria. Renal biopsy revealed mesangioproliferative glomerulonephritis (MPGN). The early onset of the primary MPGN in this infant make us consider a possible association between the deficiency of the paternally expressed genes from the 15q11-q13 region and the renal disease.

The profile of gene expression and role of nuclear factor kappa B on glomerular injury in rats with Thy-1 nephritis

Mesangioproliferative glomerulonephritis (MsPGN) is a disease of high incidence in humans. Rats with Thy-1 nephritis (Thy-1 N) are used as an animal model for studying MsPGN. Although several studies have demonstrated that many pathological factors could cause the injury of glomerular mesangial cells (GMCs) in Thy-1 N, changes of profile and the molecular mechanism of the disease (i.e. the role of transcription factors) at intervals remain unclear. The purpose of this study was to identify the changes in gene expression profile and to observe the role of nuclear factor kappa B (NF-kappaB) on the pathological change of renal tissue in Thy-1 N rats. Our results showed that the pathological changes of GMCs in Thy-1 N included three phases: apoptosis (40 min), necrosis (24 h) and proliferation (7 days). Concomitantly, at 40 min and on day 7, the up-regulation of 341 genes and 250 genes were observed, while 392 genes and 119 genes were down-regulated in Thy-1 N. Expression of interleukin (IL)-1beta, IL-6, proliferating cell nuclear antigen, alpha-smooth muscle actin, collagen type IV and excretion of urinary protein was increased in rats with Thy-1 N and decreased in pyrrolidine dithiocarbamate-treated rats with Thy-1 N. These data indicated that the significant changes in the gene profile were coupled with the pathological changes of Thy-1 N, and activation of NF-kappaB may contribute to the pathogenesis of GMCs apoptosis, proliferation, extracelluar matrix accumulation and proteinuria in Thy-1 N.

Sublytic complement C5b-9 complexes induce thrombospondin-1 production in rat glomerular mesangial cells via PI3-k/Akt: association with activation of latent transforming growth factor-beta1

Mesangial cell proliferation is a common cellular response to a variety of different types of glomerular injury. Complement C5b-9 is a prime candidate to mediate mesangial cell proliferation, especially sublytic C5b-9, which can induce the production of multiple inflammatory factors and cytokines. Transforming growth factor (TGF)-beta1 plays a major role in the accumulation of extracellular matrix (ECM), while thrombospondin (TSP)-1 has been identified as an activator of latent TGF-beta1 in an in vitro system. Using rat glomerular mesangial cells (GMCs) as a model system, we assessed the effect of sublytic C5b-9 on the expression of TSP-1 and TGF-beta1 and explored the relevant pathway of signal transduction. First, we ensured the concentrations of anti-Thy1 antibody and complement, which were regarded as a sublytic C5b-9 dose, and examined whether the sublytic C5b-9 induced expression of TSP-1 in rat GMCs which, in turn, activated latent TGF-beta1 by real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Then, we investigated the role of the PI3-k/Akt pathway in sublytic C5b-9-induced TSP-1 production in rat GMCs by Western blot analysis. The addition of sublytic C5b-9 (5% anti-Thy1 antibody and 4% normal serum) to rat GMCs induced activation of latent TGF-beta1 via TSP-1. The addition of sublytic C5b-9 apparently increased the protein of Akt phosphorylation, whereas PI3-k inhibitor LY294002 could clearly reduce the increase of TSP-1 induced by sublytic C5b-9. These results indicate that TSP-1 is an activator of latent TGF-beta1 in sublytic C5b-9-induced rat GMCs; furthermore, the PI3-k/Akt signal transduction pathway may play a key role in sublytic C5b-9-induced TSP-1 production.