Effect of proline-rich polypeptide on various lines of tumour cells, normal bone marrow and giantcell tumour stromal tissue

The aim of the study was to assess the effect of proline-rich polypeptide (PRP) on bone marrow stromal stem cells in vivo and in vitro and on tumour cell lines. Methods. Isolation of giant-cell tumour (GCT) stromal cells and obtaining these cell strains; obtaining normal bone marrow stromal cell strains; PRP administration to rats; bone marrow cell explantation into cultures; PRP addition to cell cultures. Results. Various routes and doses of PRP administration to rats increased the multipotent mesenchymal stromal cell (MMSC) concentration in the bone marrow. PRP addition to normal bone marrow MMSC cultures increased cell proliferation 1.5– 2.5-fold, whereas PRP addition to GCT MMSC cultures inhibited cell proliferation 1.5–2-fold. Both proliferation inhibition and no PRP effect on proliferation were observed in tumour cell cultures. Conclusions. PRP administration to rats increased MMSC concentration in the normal bone marrow, and PRP addition to tissue cultures revealed opposite effects of PRP on cell proliferation. Keywords: Proline-rich polypeptide (PRP), multipotent mesenchymal stromal cells (MMSC).Мета дослідження – вивчення впливу багатого на пролін поліпеп тиду (ПБП) на стовбурові клітини строми кісткового мозку in vivo та in vitro і лінії пухлинних клітин. Методи. Виділення стромальних клітин гігантоклітинної пухлнии (ГКП) і отримання штамів цих клітин, а також штамів стромальних клітин нормального кісткового мозку, введення ПБП щурам, експлантація в культуру кістковомозкових клітин, додавання ПБП у культури клітин. Результаты. Різні способи і дози введення ПБП щурам збільшують концентрацію мультипотентних мезенхімальних стромальних клітин (ММСК) у кістковому мозку. Додавання ПБП у культури ММСК нормального кісткового мозку призводить до зростання проліферативної активності клітин у 1,5–2,5 разу, внесення ПБП у культури ММСК ГКП інгібує проліферацію клітин у 1,5–2 разу. У культурах пухлинних клітин спостерігається як пригнічення пухлинних клітин, так і відсутність впливу поліпептиду на проліферацію. Висновки. Введення ПБП щурам підвищує концентрацію ММСК у нормальному кістковому мозку, а за додавання ПБП у культуру тканин виявлено його різноспрямовану дію на проліферацію клітин. Ключові слова: багатий на пролін поліпептид, мультипотентні мезенхімальні стромальні клітини.Цель исследования – изучение влияния богатого пролином полипептида (ПБП) на стволовые клетки стромы костного мозга in vivo и in vitro и линии опухолевых клеток. Методы. Выделение стромальных клеток гигантоклеточной опухоли (ГКО) и получение штаммов этих клеток, а также штаммов стромальных клеток нормального костного мозга, введение ПБП крысам, эксплантация в культуру костномозговых клеток, добавление ПБП в культуры клеток. Результаты. Различные способы и дозы введения ПБП крысам увеличивают концентрацию мультипотентных мезенхимальных стромальных клеток (ММСК) в костном мозге. Добавление ПБП в культуры ММСК нормального костного мозга приводит к возрастанию пролиферативной активности клеток в 1,5–2,5 раза, внесение ПБП в культуры ММСК ГКО ингибирует пролиферацию клеток в 1,5–2 раза. В культурах опухолевых клеток наблюдалось как угнетение, так и отсутствие влияния полипептида на пролиферацию. Выводы. Введение ПБП крысам повышает концентрацию ММСК в нормальном костном мозге, а при добавлении ПБП в культуру тканей выявлено его разнонаправленное действие на пролиферацию клеток. Ключевые слова: богатый пролином полипептид, мультипотентные мезенхимальные стромальные клетки

Limiting transport steps and novel interactions of Connexin-43 along the secretory pathway.

Connexins are four-transmembrane-domain proteins expressed in all vertebrates which form permeable gap junction channels that connect cells. Here, we analysed Connexin-43 (Cx43) transport to the plasma membrane and studied the effects of small GTPases acting along the secretory pathway. We show that both GTP- and GDP-restricted Sar1 prevents exit of Cx43 from the endoplasmic reticulum (ER), but only GTP-restricted Sar1 arrests Cx43 in COP II-coated ER exit sites and accumulates 14-3-3 proteins in the ER fraction. FRET-FLIM data confirm that already in ER exit sites Cx43 exists in oligomeric form, suggesting an in vivo role for 14-3-3 in Cx43 oligomerization. Exit of Cx43 from the ER can be blocked by other factors—such as expression of the β subunit of the COP I coat or p50/dynamitin that acts on the microtubule-based dynein motor complex. GTP-restricted Arf1 blocks Cx43 in the Golgi. Lastly, we show that GTP-restricted Arf6 removes Cx43 gap junction plaques from the cell–cell interface and targets them to degradation. These data provide a molecular explanation of how small GTPases act to regulate Cx43 transport through the secretory pathway, facilitating or abolishing cell–cell communication through gap junctions

Energetic cooperation via ion-permeable junctions in mixed animal cell cultures

AbstractLow ouabain concentration (1 × 10−4 M) is shown to decrease intracellular K+ (K+in) and to increase intracellular Na+ (Na+in) in human fibroblast cell cultures. The same ouabain concentration was without effect upon K+in ad Na+in in rodent cultures such as BHK-21, mouse fibroblasts and rat glyoma C6 cells. K+in and Na+in in the mixed cultures of human and BHK-21 fibroblasts or human and mouse fibroblasts were found to be resistant to 1 × 10−4 M ouabain whereas that of the mixtures of human and rat glyoma C6 cells proved to be ouabain-sensitive. The gap-junction-mediated dye transfer was revealed between human and BHK-21 cells. Such an effect was very small in the human-C6 cell mixed culture. It is concluded that cells with active ion pumps can support the maintenance of K+ and Na+ gradients in cells with inactive pumps, provided that effective ion transport via gap junctions takes place

Thermo-photobiomodulation of stem cells

The most important task of cell transplantology is to activate the proliferative potential of mesenchymal stem cells (MSCs) before receiving bone marrow cells from a donor. This is necessary to increase a sufficient number of MSCs in early passages, when the probability of chromosomal mutations is still low. The proliferative activity of cells can be activated using photobiomodulation (PBM) by exposure to lowintensity laser radiation in the visible and near-infrared ranges. Recently, it was shown in vitro that the combination of PBM and moderate laserinduced heating can lead to a significant increase in the efficiency of MSC colony formation. The main objectives of the study are to find the optimal parameters for such a combined effect and answer the question about the possibility of a synergistic effect of thermal heating and laser radiation. MSCs isolated from rat bone marrow were used for the experiments. MSCs were exposed to short-term laser radiation of moderate power with a wavelength of 980 nm and an energy density of 68-340 J/cm2, accompanied by moderate heating of the cell suspension. Vials with grown colonies were photographed, then their number, size and number of cells in individual colonies were determined using special digital image processing methods. It was found that under optimal parameters, exposure to laser radiation of moderate power leads to an increase in the number of colonies by 4.1±0.5 times, and the total number of cells by 3.3±0.4 times compared to the control. It has been shown that this increase in cell number occurs as a result of the synergistic effect of photobiomodulation and moderate heating. Activation of colony formation after laser stimulation of MSCs occurs due to the migration of cells from the initially formed colonies with the subsequent formation of additional colonies by separated cells

Recent Advances of Flowering Locus T Gene in Higher Plants

Flowering Locus T (FT) can promote flowering in the plant photoperiod pathway and also facilitates vernalization flowering pathways and other ways to promote flowering. The expression of products of the FT gene is recognized as important parts of the flowering hormone and can induce flowering by long-distance transportation. In the present study, many FT-like genes were isolated, and the transgenic results show that FT gene can promote flowering in plants. This paper reviews the progress of the FT gene and its expression products to provide meaningful information for further studies of the functions of FT genes

FTIP1 Is an Essential Regulator Required for Florigen Transport

FT-INTERACTING PROTEIN 1 is a novel protein that is involved in transporting florigen, a long-known mobile signal that induces flowering in plants in response to day length, from companion cells to sieve elements in the phloem of Arabidopsis

CsFTL3, a chrysanthemum FLOWERING LOCUS T-like gene, is a key regulator of photoperiodic flowering in chrysanthemums

Chrysanthemum is a typical short-day (SD) plant that responds to shortening daylength during the transition from the vegetative to the reproductive phase. FLOWERING LOCUS T (FT)/Heading date 3a (Hd3a) plays a pivotal role in the induction of phase transition and is proposed to encode a florigen. Three FT-like genes were isolated from Chrysanthemum seticuspe (Maxim.) Hand.-Mazz. f. boreale (Makino) H. Ohashi & Yonek, a wild diploid chrysanthemum: CsFTL1, CsFTL2, and CsFTL3. The organ-specific expression patterns of the three genes were similar: they were all expressed mainly in the leaves. However, their response to daylength differed in that under SD (floral-inductive) conditions, the expression of CsFTL1 and CsFTL2 was down-regulated, whereas that of CsFTL3 was up-regulated. CsFTL3 had the potential to induce early flowering since its overexpression in chrysanthemum could induce flowering under non-inductive conditions. CsFTL3-dependent graft-transmissible signals partially substituted for SD stimuli in chrysanthemum. The CsFTL3 expression levels in the two C. seticuspe accessions that differed in their critical daylengths for flowering closely coincided with the flowering response. The CsFTL3 expression levels in the leaves were higher under floral-inductive photoperiods than under non-inductive conditions in both the accessions, with the induction of floral integrator and/or floral meristem identity genes occurring in the shoot apexes. Taken together, these results indicate that the gene product of CsFTL3 is a key regulator of photoperiodic flowering in chrysanthemums

Geminivirus-Mediated Delivery of Florigen Promotes Determinate Growth in Aerial Organs and Uncouples Flowering from Photoperiod in Cotton

This article discusses geminivirus-mediated delivery of florigen. Florigen acts as a general growth hormone, advancing determinate growth. The findings extend our understanding of florigen as a general growth hormone and could benefit crop management techniques

Repression of Flowering by the miR172 Target SMZ

The flowering repressors SMZ and FLM, members of the AP-2 and MADS domain transcription factor families, unexpectedly work together to regulate flowering time via their effects on expression of the FT gene